nova.conf - configuration options¶

(Integer) Interval to pull network bandwidth usage info.

Not supported on all hypervisors. If a hypervisor doesn’t support bandwidth usage, it will not get the info in the usage events.

Possible values:

• 0: Will run at the default periodic interval.
• Any value < 0: Disables the option.
• Any positive integer in seconds.

(String) This option is the name of the virtual interface of the VM on which the bridge will be built. While it was originally designed to be used only by nova-network, it is also used by libvirt for the bridge interface name.

Possible values:

• Any valid virtual interface name, such as ‘eth0’

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Expiry interval (in seconds) for LDAP DNS driver Start of Authority

Time interval, a secondary/slave DNS server holds the information before it is no longer considered authoritative.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Total time to wait in seconds for an instance toperform a clean shutdown.

It determines the overall period (in seconds) a VM is allowed to perform a clean shutdown. While performing stop, rescue and shelve, rebuild operations, configuring this option gives the VM a chance to perform a controlled shutdown before the instance is powered off. The default timeout is 60 seconds.

The timeout value can be overridden on a per image basis by means of os_shutdown_timeout that is an image metadata setting allowing different types of operating systems to specify how much time they need to shut down cleanly.

Possible values:

• Any positive integer in seconds (default value is 60).

(Boolean) Determines whether unused gateway devices, both VLAN and bridge, are deleted if the network is in nova-network VLAN mode and is multi-hosted.

Related options:

• use_neutron
• vpn_ip
• fake_network

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) This is the name of the network interface for public IP addresses. The default is ‘eth0’.

Possible values:

• Any string representing a network interface name

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) This option determines the number of addresses in each private subnet.

Please note that this option is only used when using nova-network instead of Neutron in your deployment.

Possible values:

• Any positive integer that is less than or equal to the available network size. Note that if you are creating multiple networks, they must all fit in the available IP address space. The default is 256.

Related options:

• use_neutron
• num_networks

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Boolean) Enable new services on this host automatically.

When a new service (for example “nova-compute”) starts up, it gets registered in the database as an enabled service. Sometimes it can be useful to register new services in disabled state and then enabled them at a later point in time. This option can set this behavior for all services per host.

Possible values:

• True: Each new service is enabled as soon as it registers itself.
• False: Services must be enabled via a REST API call or with the CLI with nova service-enable <hostname> <binary>, otherwise they are not ready to use.

(String) Hostmaster for LDAP DNS driver Statement of Authority

Possible values:

• Any valid string representing LDAP DNS hostmaster.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Unknown) Number of huge/large memory pages to reserved per NUMA host cell.

Possible values:

• A list of valid key=value which reflect NUMA node ID, page size (Default unit is KiB) and number of pages to be reserved.

reserved_huge_pages = node:0,size:2048,count:64 reserved_huge_pages = node:1,size:1GB,count:1

In this example we are reserving on NUMA node 0 64 pages of 2MiB and on NUMA node 1 1 page of 1GiB.

(Boolean) Enable neutron as the backend for networking.

Determine whether to use Neutron or Nova Network as the back end. Set to true to use neutron.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) Path to the rootwrap configuration file.

Goal of the root wrapper is to allow a service-specific unprivileged user to run a number of actions as the root user in the safest manner possible. The configuration file used here must match the one defined in the sudoers entry.

(String) IP address on which the metadata API will listen.

The metadata API service listens on this IP address for incoming requests.

(Boolean) Force injection to take place on a config drive

When this option is set to true configuration drive functionality will be forced enabled by default, otherwise user can still enable configuration drives via the REST API or image metadata properties.

Possible values:

• True: Force to use of configuration drive regardless the user’s input in the REST API call.
• False: Do not force use of configuration drive. Config drives can still be enabled via the REST API or image metadata properties.

Related options:

• Use the ‘mkisofs_cmd’ flag to set the path where you install the genisoimage program. If genisoimage is in same path as the nova-compute service, you do not need to set this flag.
• To use configuration drive with Hyper-V, you must set the ‘mkisofs_cmd’ value to the full path to an mkisofs.exe installation. Additionally, you must set the qemu_img_cmd value in the hyperv configuration section to the full path to an qemu-img command installation.

(Boolean) Autoassigning floating IP to VM

When set to True, floating IP is auto allocated and associated to the VM upon creation.

Related options:

• use_neutron: this options only works with nova-network.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) If specified, Nova checks if the availability_zone of every instance matches what the database says the availability_zone should be for the specified dns_domain.

Related options:

• use_neutron: this options only works with nova-network.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) The lifetime of a DHCP lease, in seconds. The default is 86400 (one day).

Possible values:

• Any positive integer value.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) The top-level directory for maintaining Nova’s state.

This directory is used to store Nova’s internal state. It is used by a variety of other config options which derive from this. In some scenarios (for example migrations) it makes sense to use a storage location which is shared between multiple compute hosts (for example via NFS). Unless the option instances_path gets overwritten, this directory can grow very large.

Possible values:

• The full path to a directory. Defaults to value provided in pybasedir.

(Integer) Interval between instance network information cache updates.

Number of seconds after which each compute node runs the task of querying Neutron for all of its instances networking information, then updates the Nova db with that information. Nova will never update it’s cache if this option is set to 0. If we don’t update the cache, the metadata service and nova-api endpoints will be proxying incorrect network data about the instance. So, it is not recommended to set this option to 0.

Possible values:

• Any positive integer in seconds.
• Any value <=0 will disable the sync. This is not recommended.

(String) This option determines the IP address for the network metadata API server.

This is really the client side of the metadata host equation that allows nova-network to find the metadata server when doing a default multi host networking.

Possible values:

• Any valid IP address. The default is the address of the Nova API server.

Related options:

• metadata_port

(String) Firewall driver to use with nova-network service.

This option only applies when using the nova-network service. When using another networking services, such as Neutron, this should be to set to the nova.virt.firewall.NoopFirewallDriver.

Possible values:

• nova.virt.firewall.IptablesFirewallDriver
• nova.virt.firewall.NoopFirewallDriver
• nova.virt.libvirt.firewall.IptablesFirewallDriver
• [...]

Related options:

• use_neutron: This must be set to False to enable nova-network networking

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) Configuration drive format

Configuration drive format that will contain metadata attached to the instance when it boots.

Possible values:

• iso9660: A file system image standard that is widely supported across operating systems. NOTE: Mind the libvirt bug (https://bugs.launchpad.net/nova/+bug/1246201) - If your hypervisor driver is libvirt, and you want live migrate to work without shared storage, then use VFAT.
• vfat: For legacy reasons, you can configure the configuration drive to use VFAT format instead of ISO 9660.

Related options:

• This option is meaningful when one of the following alternatives occur: 1. force_config_drive option set to ‘true’ 2. the REST API call to create the instance contains an enable flag for config drive option 3. the image used to create the instance requires a config drive, this is defined by img_config_drive property for that image.
• A compute node running Hyper-V hypervisor can be configured to attach configuration drive as a CD drive. To attach the configuration drive as a CD drive, set config_drive_cdrom option at hyperv section, to true.

(Integer) Time before a shelved instance is eligible for removal from a host.

By default this option is set to 0 and the shelved instance will be removed from the hypervisor immediately after shelve operation. Otherwise, the instance will be kept for the value of shelved_offload_time(in seconds) so that during the time period the unshelve action will be faster, then the periodic task will remove the instance from hypervisor after shelved_offload_time passes.

Possible values:

• 0: Instance will be immediately offloaded after being shelved.
• Any value < 0: An instance will never offload.
• Any positive integer in seconds: The instance will exist for the specified number of seconds before being offloaded.

(String) Generic property to specify the pointer type.

Input devices allow interaction with a graphical framebuffer. For example to provide a graphic tablet for absolute cursor movement.

If set, the ‘hw_pointer_model’ image property takes precedence over this configuration option.

Possible values:

• None: Uses default behavior provided by drivers (mouse on PS2 for libvirt x86)
• ps2mouse: Uses relative movement. Mouse connected by PS2
• usbtablet: Uses absolute movement. Tablet connect by USB

Related options:

• usbtablet must be configured with VNC enabled or SPICE enabled and SPICE agent disabled. When used with libvirt the instance mode should be configured as HVM.

(Floating point) This option helps you specify virtual disk to physical disk allocation ratio.

From Ocata (15.0.0) this is used to influence the hosts selected by the Placement API. Note that when Placement is used, the DiskFilter is redundant, because the Placement API will have already filtered out hosts that would have failed the DiskFilter.

A ratio greater than 1.0 will result in over-subscription of the available physical disk, which can be useful for more efficiently packing instances created with images that do not use the entire virtual disk, such as sparse or compressed images. It can be set to a value between 0.0 and 1.0 in order to preserve a percentage of the disk for uses other than instances.

NOTE: This can be set per-compute, or if set to 0.0, the value set on the scheduler node(s) or compute node(s) will be used and defaulted to 1.0.

NOTE: As of the 16.0.0 Pike release, this configuration option is ignored for the ironic.IronicDriver compute driver and is hardcoded to 1.0.

Possible values:

• Any valid positive integer or float value

(String) This is the address of the DNS server for a simple network. If this option is not specified, the default of ‘8.8.4.4’ is used.

Please note that this option is only used when using nova-network instead of Neutron in your deployment.

Possible values:

• Any valid IP address.

Related options:

• use_neutron

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) The default format an ephemeral_volume will be formatted with on creation.

Possible values:

• ext2
• ext3
• ext4
• xfs
• ntfs (only for Windows guests)

(URI) URL for LDAP server which will store DNS entries

Possible values:

• A valid LDAP URL representing the server

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Boolean) Enable periodic tasks.

If set to true, this option allows services to periodically run tasks on the manager.

In case of running multiple schedulers or conductors you may want to run periodic tasks on only one host - in this case disable this option for all hosts but one.

(String) This is the default IPv4 gateway. It is used only in the testing suite.

Please note that this option is only used when using nova-network instead of Neutron in your deployment.

Possible values:

• Any valid IP address.

Related options:

• use_neutron
• gateway_v6

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) Base distinguished name for the LDAP search query

This option helps to decide where to look up the host in LDAP.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Time interval in seconds to wait between runs for the clean up action. If set to 0, above check will be disabled. If “running_deleted_instance _action” is set to “log” or “reap”, a value greater than 0 must be set.

Possible values:

• Any positive integer in seconds enables the option.
• 0: Disables the option.
• 1800: Default value.

Related options:

• running_deleted_instance_action

(Multi-valued) One or more interfaces that bridges can forward traffic to. If any of the items in this list is the special keyword ‘all’, then all traffic will be forwarded.

Possible values:

• A list of zero or more interface names, or the word ‘all’.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) Specifies where instances are stored on the hypervisor’s disk. It can point to locally attached storage or a directory on NFS.

Possible values:

• $state_path/instances where state_path is a config option that specifies the top-level directory for maintaining nova’s state. (default) or Any string representing directory path.

(String) Hostname, FQDN or IP address of this host. Must be valid within AMQP key.

Possible values:

• String with hostname, FQDN or IP address. Default is hostname of this host.

(String) This option is no longer used since the /os-cloudpipe API was removed in the 16.0.0 Pike release. This is the public IP address for the cloudpipe VPN servers. It defaults to the IP address of the host.

Please note that this option is only used when using nova-network instead of Neutron in your deployment. It also will be ignored if the configuration option for network_manager is not set to the default of ‘nova.network.manager.VlanManager’.

Possible values:

• Any valid IP address. The default is $my_ip, the IP address of the VM.

Related options:

• network_manager
• use_neutron
• vpn_start

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) This is the number of seconds to wait before disassociating a deallocated fixed IP address. This is only used with the nova-network service, and has no effect when using neutron for networking.

Possible values:

• Any integer, zero or greater.

Related options:

• use_neutron

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) Console proxy host to be used to connect to instances on this host. It is the publicly visible name for the console host.

Possible values:

• Current hostname (default) or any string representing hostname.

(Integer) Time interval after which an instance is hard rebooted automatically.

When doing a soft reboot, it is possible that a guest kernel is completely hung in a way that causes the soft reboot task to not ever finish. Setting this option to a time period in seconds will automatically hard reboot an instance if it has been stuck in a rebooting state longer than N seconds.

Possible values:

• 0: Disables the option (default).
• Any positive integer in seconds: Enables the option.

(Boolean) This option is used mainly in testing to avoid calls to the underlying network utilities.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) The location where the network configuration files will be kept. The default is the ‘networks’ directory off of the location where nova’s Python module is installed.

Possible values

• A string containing the full path to the desired configuration directory

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(List) This option is a list of zero or more IP address ranges in your network’s DMZ that should be accepted.

Possible values:

• A list of strings, each of which should be a valid CIDR.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Number of times to retry live-migration before failing.

Possible values:

• If == -1, try until out of hosts (default)
• If == 0, only try once, no retries
• Integer greater than 0

(Integer) Interval for polling shelved instances to offload.

The periodic task runs for every shelved_poll_interval number of seconds and checks if there are any shelved instances. If it finds a shelved instance, based on the ‘shelved_offload_time’ config value it offloads the shelved instances. Check ‘shelved_offload_time’ config option description for details.

Possible values:

• Any value <= 0: Disables the option.
• Any positive integer in seconds.

Related options:

• shelved_offload_time

(Boolean) Enable resizing of filesystems via a block device.

If enabled, attempt to resize the filesystem by accessing the image over a block device. This is done by the host and may not be necessary if the image contains a recent version of cloud-init. Possible mechanisms require the nbd driver (for qcow and raw), or loop (for raw).

(String) This option is the name of the virtual interface of the VM on which the VLAN bridge will be built. While it was originally designed to be used only by nova-network, it is also used by libvirt and xenapi for the bridge interface name.

Please note that this setting will be ignored in nova-network if the configuration option for network_manager is not set to the default of ‘nova.network.manager.VlanManager’.

Possible values:

• Any valid virtual interface name, such as ‘eth0’

• Deprecated

  nova-network is deprecated, as are any related configuration options. While this option has an effect when using neutron, it incorrectly override the value provided by neutron and should therefore not be used.

(String) Scheduler message queue topic.

This is the message queue topic that the scheduler ‘listens’ on. It is used when the scheduler service is started up to configure the queue, and whenever an RPC call to the scheduler is made. There is almost never any reason to ever change this value.

Possible values:

• A valid AMQP topic name

• Deprecated

  There is no need to let users choose the RPC topic for all services - there is little gain from this. Furthermore, it makes it really easy to break Nova by using this option.

(Integer) Number of times to retry network allocation. It is required to attempt network allocation retries if the virtual interface plug fails.

Possible values:

• Any positive integer representing retry count.

(Integer) Number of seconds to randomly delay when starting the periodic task scheduler to reduce stampeding.

When compute workers are restarted in unison across a cluster, they all end up running the periodic tasks at the same time causing problems for the external services. To mitigate this behavior, periodic_fuzzy_delay option allows you to introduce a random initial delay when starting the periodic task scheduler.

Possible Values:

• Any positive integer (in seconds)
• 0 : disable the random delay

(String) The path to the custom dnsmasq configuration file, if any.

Possible values:

• The full path to the configuration file, or an empty string if there is no custom dnsmasq configuration file.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) This option determines the number of times to retry ebtables commands before giving up. The minimum number of retries is 1.

Possible values:

• Any positive integer

Related options:

• ebtables_retry_interval

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) Name or path of the tool used for ISO image creation

Use the mkisofs_cmd flag to set the path where you install the genisoimage program. If genisoimage is on the system path, you do not need to change the default value.

To use configuration drive with Hyper-V, you must set the mkisofs_cmd value to the full path to an mkisofs.exe installation. Additionally, you must set the qemu_img_cmd value in the hyperv configuration section to the full path to an qemu-img command installation.

Possible values:

• Name of the ISO image creator program, in case it is in the same directory as the nova-compute service
• Path to ISO image creator program

Related options:

• This option is meaningful when config drives are enabled.
• To use configuration drive with Hyper-V, you must set the qemu_img_cmd value in the hyperv configuration section to the full path to an qemu-img command installation.

(String) This option allows you to change the message topic used by nova-consoleauth service when communicating via the AMQP server. Nova Console Authentication server authenticates nova consoles. Users can then access their instances through VNC clients. The Nova API service uses a message queue to communicate with nova-consoleauth to get a VNC console.

Possible Values:

• ‘consoleauth’ (default) or Any string representing topic exchange name.

• Deprecated

  There is no need to let users choose the RPC topic for all services - there is little gain from this. Furthermore, it makes it really easy to break Nova by using this option.

(Integer) Number of seconds indicating how frequently the state of services on a given hypervisor is reported. Nova needs to know this to determine the overall health of the deployment.

Related Options:

• service_down_time report_interval should be less than service_down_time. If service_down_time is less than report_interval, services will routinely be considered down, because they report in too rarely.

(Boolean) Determine if instance should boot or fail on VIF plugging timeout.

Nova sends a port update to Neutron after an instance has been scheduled, providing Neutron with the necessary information to finish setup of the port. Once completed, Neutron notifies Nova that it has finished setting up the port, at which point Nova resumes the boot of the instance since network connectivity is now supposed to be present. A timeout will occur if the reply is not received after a given interval.

This option determines what Nova does when the VIF plugging timeout event happens. When enabled, the instance will error out. When disabled, the instance will continue to boot on the assumption that the port is ready.

Possible values:

• True: Instances should fail after VIF plugging timeout
• False: Instances should continue booting after VIF plugging timeout

(Boolean) When this option is True, whenever a DNS entry must be updated, a fanout cast message is sent to all network hosts to update their DNS entries in multi-host mode.

Related options:

• use_neutron

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) nova-console-proxy is used to set up multi-tenant VM console access. This option allows pluggable driver program for the console session and represents driver to use for the console proxy.

Possible values:

• A string representing fully classified class name of console driver.

• Deprecated

  This option no longer does anything. Previously this option had only two valid, in-tree values: nova.console.xvp.XVPConsoleProxy and nova.console.fake.FakeConsoleProxy. The latter of these was only used in tests and has since been replaced.

(Boolean) Determine whether to allow network traffic from same network.

When set to true, hosts on the same subnet are not filtered and are allowed to pass all types of traffic between them. On a flat network, this allows all instances from all projects unfiltered communication. With VLAN networking, this allows access between instances within the same project.

This option only applies when using the nova-network service. When using another networking services, such as Neutron, security groups or other approaches should be used.

Possible values:

• True: Network traffic should be allowed pass between all instances on the same network, regardless of their tenant and security policies
• False: Network traffic should not be allowed pass between instances unless it is unblocked in a security group

Related options:

• use_neutron: This must be set to False to enable nova-network networking
• firewall_driver: This must be set to nova.virt.libvirt.firewall.IptablesFirewallDriver to ensure the libvirt firewall driver is enabled.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) This option allows you to specify the L3 management library to be used.

Possible values:

• Any dot-separated string that represents the import path to an L3 networking library.

Related options:

• use_neutron

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Boolean) This option is used to enable or disable quota checking for tenant networks.

Related options:

• quota_networks

• Deprecated

  CRUD operations on tenant networks are only available when using nova-network and nova-network is itself deprecated.

(Boolean) Assign IPv6 and IPv4 addresses when creating instances.

Related options:

• use_neutron: this only works with nova-network.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Number of seconds to wait between runs of the image cache manager.

Possible values:

• 0: run at the default rate.
• -1: disable
• Any other value

(Port number) This option determines the port used for the metadata API server.

Related options:

• metadata_host

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Boolean) When this option is True, a call is made to release the DHCP for the instance when that instance is terminated.

Related options:

• use_neutron

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Boolean) Enable use of copy-on-write (cow) images.

QEMU/KVM allow the use of qcow2 as backing files. By disabling this, backing files will not be used.

(Integer) This option represents the number of networks to create if not explicitly specified when the network is created. The only time this is used is if a CIDR is specified, but an explicit network_size is not. In that case, the subnets are created by diving the IP address space of the CIDR by num_networks. The resulting subnet sizes cannot be larger than the configuration option network_size; in that event, they are reduced to network_size, and a warning is logged.

Please note that this option is only used when using nova-network instead of Neutron in your deployment.

Possible values:

• Any positive integer is technically valid, although there are practical limits based upon available IP address space and virtual interfaces.

Related options:

• use_neutron
• network_size

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Retry interval (in seconds) for LDAP DNS driver Start of Authority

Time interval, a secondary/slave DNS server should wait, if an attempt to transfer zone failed during the previous refresh interval.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Amount of memory in MB to reserve for the host so that it is always available to host processes. The host resources usage is reported back to the scheduler continuously from nova-compute running on the compute node. To prevent the host memory from being considered as available, this option is used to reserve memory for the host.

Possible values:

• Any positive integer representing amount of memory in MB to reserve for the host.

(String) Defines which driver to use for controlling virtualization.

Possible values:

• libvirt.LibvirtDriver
• xenapi.XenAPIDriver
• fake.FakeDriver
• ironic.IronicDriver
• vmwareapi.VMwareVCDriver
• hyperv.HyperVDriver

(Boolean) When this option is set to True, the dns1 and dns2 servers for the network specified by the user on boot will be used for DNS, as well as any specified in the dns_server option.

Related options:

• dns_server

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Maximum number of devices that will result in a local image being created on the hypervisor node.

A negative number means unlimited. Setting max_local_block_devices to 0 means that any request that attempts to create a local disk will fail. This option is meant to limit the number of local discs (so root local disc that is the result of –image being used, and any other ephemeral and swap disks). 0 does not mean that images will be automatically converted to volumes and boot instances from volumes - it just means that all requests that attempt to create a local disk will fail.

Possible values:

• 0: Creating a local disk is not allowed.
• Negative number: Allows unlimited number of local discs.
• Positive number: Allows only these many number of local discs. (Default value is 3).

(Integer) Maximum number of live migrations to run concurrently. This limit is enforced to avoid outbound live migrations overwhelming the host/network and causing failures. It is not recommended that you change this unless you are very sure that doing so is safe and stable in your environment.

Possible values:

• 0 : treated as unlimited.
• Negative value defaults to 0.
• Any positive integer representing maximum number of live migrations to run concurrently.

(String) This is the default IPv6 gateway. It is used only in the testing suite.

Please note that this option is only used when using nova-network instead of Neutron in your deployment.

Possible values:

• Any valid IP address.

Related options:

• use_neutron
• gateway

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Limits the maximum number of instance builds to run concurrently by nova-compute. Compute service can attempt to build an infinite number of instances, if asked to do so. This limit is enforced to avoid building unlimited instance concurrently on a compute node. This value can be set per compute node.

Possible Values:

• 0 : treated as unlimited.
• Any positive integer representing maximum concurrent builds.

(Boolean) Determine if monkey patching should be applied.

Related options:

• monkey_patch_modules: This must have values set for this option to have any effect

(String) The directory where the Nova binaries are installed.

This option is only relevant if the networking capabilities from Nova are used (see services below). Nova’s networking capabilities are targeted to be fully replaced by Neutron in the future. It is very unlikely that you need to change this option from its default value.

Possible values:

• The full path to a directory.

(String) Defines which physical CPUs (pCPUs) can be used by instance virtual CPUs (vCPUs).

Possible values:

• A comma-separated list of physical CPU numbers that virtual CPUs can be allocated to by default. Each element should be either a single CPU number, a range of CPU numbers, or a caret followed by a CPU number to be excluded from a previous range. For example:

vcpu_pin_set = “4-12,^8,15”

(Integer) This option determines how many times nova-network will attempt to create a unique MAC address before giving up and raising a VirtualInterfaceMacAddressException error.

Possible values:

• Any positive integer. The default is 5.

Related options:

• use_neutron

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) This expression, if defined, will select any matching iptables rules and place them at the top when applying metadata changes to the rules.

Possible values:

• Any string representing a valid regular expression, or an empty string

Related options:

• iptables_bottom_regex

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) Sets the scope of the check for unique instance names.

The default doesn’t check for unique names. If a scope for the name check is set, a launch of a new instance or an update of an existing instance with a duplicate name will result in an ‘’InstanceExists’’ error. The uniqueness is case-insensitive. Setting this option can increase the usability for end users as they don’t have to distinguish among instances with the same name by their IDs.

Possible values:

• ‘’: An empty value means that no uniqueness check is done and duplicate names are possible.
• “project”: The instance name check is done only for instances within the same project.
• “global”: The instance name check is done for all instances regardless of the project.

(String) The name of a logging configuration file. This file is appended to any existing logging configuration files. For details about logging configuration files, see the Python logging module documentation. Note that when logging configuration files are used then all logging configuration is set in the configuration file and other logging configuration options are ignored (for example, logging_context_format_string).

• Mutable

  This option can be changed without restarting.

(String) Abstracts out IPv6 address generation to pluggable backends.

nova-network can be put into dual-stack mode, so that it uses both IPv4 and IPv6 addresses. In dual-stack mode, by default, instances acquire IPv6 global unicast addresses with the help of stateless address auto-configuration mechanism.

Related options:

• use_neutron: this option only works with nova-network.
• use_ipv6: this option only works if ipv6 is enabled for nova-network.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Minimum interval (in seconds) for LDAP DNS driver Start of Authority

It is Minimum time-to-live applies for all resource records in the zone file. This value is supplied to other servers how long they should keep the data in cache.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Interval to sync power states between the database and the hypervisor.

The interval that Nova checks the actual virtual machine power state and the power state that Nova has in its database. If a user powers down their VM, Nova updates the API to report the VM has been powered down. Should something turn on the VM unexpectedly, Nova will turn the VM back off to keep the system in the expected state.

Possible values:

• 0: Will run at the default periodic interval.
• Any value < 0: Disables the option.
• Any positive integer in seconds.

Related options:

• If handle_virt_lifecycle_events in workarounds_group is false and this option is negative, then instances that get out of sync between the hypervisor and the Nova database will have to be synchronized manually.

(Integer) This option represents the number of IP addresses to reserve at the top of the address range for VPN clients. It also will be ignored if the configuration option for network_manager is not set to the default of ‘nova.network.manager.VlanManager’.

Possible values:

• Any integer, 0 or greater.

Related options:

• use_neutron
• network_manager

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(Integer) Refresh interval (in seconds) for LDAP DNS driver Start of Authority

Time interval, a secondary/slave DNS server waits before requesting for primary DNS server’s current SOA record. If the records are different, secondary DNS server will request a zone transfer from primary.

NOTE: Lower values would cause more traffic.

• Deprecated

  nova-network is deprecated, as are any related configuration options.

(String) The topic network nodes listen on

• Deprecated

  There is no need to let users choose the RPC topic for all services - there is little gain from this. Furthermore, it makes it really easy to break Nova by using this option.

(String) Path to an optional certificate file or CA bundle to verify dynamic vendordata REST services ssl certificates against.

Possible values:

• An empty string, or a path to a valid certificate file

Related options:

• vendordata_providers
• vendordata_dynamic_targets
• vendordata_dynamic_connect_timeout
• vendordata_dynamic_read_timeout
• vendordata_dynamic_failure_fatal

(String) When gathering the existing metadata for a config drive, the EC2-style metadata is returned for all versions that don’t appear in this option. As of the Liberty release, the available versions are:

• 1.0
• 2007-01-19
• 2007-03-01
• 2007-08-29
• 2007-10-10
• 2007-12-15
• 2008-02-01
• 2008-09-01
• 2009-04-04

The option is in the format of a single string, with each version separated by a space.

Possible values:

• Any string that represents zero or more versions, separated by spaces.

(Integer) Maximum wait time for an external REST service to connect.

Possible values:

• Any integer with a value greater than three (the TCP packet retransmission timeout). Note that instance start may be blocked during this wait time, so this value should be kept small.

Related options:

• vendordata_providers
• vendordata_dynamic_targets
• vendordata_dynamic_ssl_certfile
• vendordata_dynamic_read_timeout
• vendordata_dynamic_failure_fatal

(Boolean) Operators can turn off the ability for a user to take snapshots of their instances by setting this option to False. When disabled, any attempt to take a snapshot will result in a HTTP 400 response (“Bad Request”).

• Deprecated

  This option disables the createImage server action API in a non-discoverable way and is thus a barrier to interoperability. Also, it is not used for other APIs that create snapshots like shelve or createBackup. Disabling snapshots should be done via policy if so desired.

(String) Cloud providers may store custom data in vendor data file that will then be available to the instances via the metadata service, and to the rendering of config-drive. The default class for this, JsonFileVendorData, loads this information from a JSON file, whose path is configured by this option. If there is no path set by this option, the class returns an empty dictionary.

Possible values:

• Any string representing the path to the data file, or an empty string (default).

(Boolean) When True, the ‘X-Forwarded-For’ header is treated as the canonical remote address. When False (the default), the ‘remote_address’ header is used.

You should only enable this if you have an HTML sanitizing proxy.

(Boolean) Should failures to fetch dynamic vendordata be fatal to instance boot?

Related options:

• vendordata_providers
• vendordata_dynamic_targets
• vendordata_dynamic_ssl_certfile
• vendordata_dynamic_connect_timeout
• vendordata_dynamic_read_timeout

(Integer) Mute child interval.

Number of seconds after which a lack of capability and capacity update the child cell is to be treated as a mute cell. Then the child cell will be weighed as recommend highly that it be skipped.

Possible values:

• An integer, corresponding to the interval time in seconds.

(String) Topic.

This is the message queue topic that cells nodes listen on. It is used when the cells service is started up to configure the queue, and whenever an RPC call to the scheduler is made.

Possible values:

• cells: This is the recommended and the default value.

• Deprecated

  Configurable RPC topics provide little value and can result in a wide variety of errors. They should not be used.

(String) Type of cell.

When cells feature is enabled the hosts in the OpenStack Compute cloud are partitioned into groups. Cells are configured as a tree. The top-level cell’s cell_type must be set to api. All other cells are defined as a compute cell by default.

Related option:

• quota_driver: Disable quota checking for the child cells. (nova.quota.NoopQuotaDriver)

(Floating point) Ram weight multiplier.

Multiplier used for weighing ram. Negative numbers indicate that Compute should stack VMs on one host instead of spreading out new VMs to more hosts in the cell.

Possible values:

• Numeric multiplier

(Floating point) Mute weight multiplier.

Multiplier used to weigh mute children. Mute children cells are recommended to be skipped so their weight is multiplied by this negative value.

Possible values:

• Negative numeric number

(Boolean) Enable cell v1 functionality.

Note that cells v1 is considered experimental and not recommended for new Nova deployments. Cells v1 is being replaced by cells v2 which starting in the 15.0.0 Ocata release, all Nova deployments are at least a cells v2 cell of one. Setting this option, or any other options in the [cells] group, is not required for cells v2.

When this functionality is enabled, it lets you to scale an OpenStack Compute cloud in a more distributed fashion without having to use complicated technologies like database and message queue clustering. Cells are configured as a tree. The top-level cell should have a host that runs a nova-api service, but no nova-compute services. Each child cell should run all of the typical nova-* services in a regular Compute cloud except for nova-api. You can think of cells as a normal Compute deployment in that each cell has its own database server and message queue broker.

Related options:

• name: A unique cell name must be given when this functionality is enabled.
• cell_type: Cell type should be defined for all cells.

(Integer) DB check interval.

Cell state manager updates cell status for all cells from the DB only after this particular interval time is passed. Otherwise cached status are used. If this value is 0 or negative all cell status are updated from the DB whenever a state is needed.

Possible values:

• Interval time, in seconds.

(Integer) Maximum hop count

When processing a targeted message, if the local cell is not the target, a route is defined between neighbouring cells. And the message is processed across the whole routing path. This option defines the maximum hop counts until reaching the target.

Possible values:

• Positive integer value

(String) Name of the current cell.

This value must be unique for each cell. Name of a cell is used as its id, leaving this option unset or setting the same name for two or more cells may cause unexpected behaviour.

Related options:

• enabled: This option is meaningful only when cells service is enabled

(List) Scheduler weight classes.

Weigher classes the cells scheduler should use. An entry of “nova.cells.weights.all_weighers” maps to all cell weighers included with nova. As of the Mitaka release the following weight classes are available:

mute_child: Downgrades the likelihood of child cells being chosen for scheduling requests, which haven’t sent capacity or capability updates in a while. Options include mute_weight_multiplier (multiplier for mute children; value should be negative).

ram_by_instance_type: Select cells with the most RAM capacity for the instance type being requested. Because higher weights win, Compute returns the number of available units for the instance type requested. The ram_weight_multiplier option defaults to 10.0 that adds to the weight by a factor of 10. Use a negative number to stack VMs on one host instead of spreading out new VMs to more hosts in the cell.

weight_offset: Allows modifying the database to weight a particular cell. The highest weight will be the first cell to be scheduled for launching an instance. When the weight_offset of a cell is set to 0, it is unlikely to be picked but it could be picked if other cells have a lower weight, like if they’re full. And when the weight_offset is set to a very high value (for example, ‘999999999999999’), it is likely to be picked if another cell do not have a higher weight.

(Integer) Instance updated at threshold

Number of seconds after an instance was updated or deleted to continue to update cells. This option lets cells manager to only attempt to sync instances that have been updated recently. i.e., a threshold of 3600 means to only update instances that have modified in the last hour.

Possible values:

• Threshold in seconds

Related options:

• This value is used with the instance_update_num_instances value in a periodic task run.

(Floating point) Reserve percentage

Percentage of cell capacity to hold in reserve, so the minimum amount of free resource is considered to be;

min_free = total * (reserve_percent / 100.0)

This option affects both memory and disk utilization.

The primary purpose of this reserve is to ensure some space is available for users who want to resize their instance to be larger. Note that currently once the capacity expands into this reserve space this option is ignored.

Possible values:

• An integer or float, corresponding to the percentage of cell capacity to be held in reserve.

(Boolean) Allow attach between instance and volume in different availability zones.

If False, volumes attached to an instance must be in the same availability zone in Cinder as the instance availability zone in Nova. This also means care should be taken when booting an instance from a volume where source is not “volume” because Nova will attempt to create a volume using the same availability zone as what is assigned to the instance. If that AZ is not in Cinder (or allow_availability_zone_fallback=False in cinder.conf), the volume create request will fail and the instance will fail the build request. By default there is no availability zone restriction on volume attach.

(Integer) Number of times cinderclient should retry on any failed http call. 0 means connection is attempted only once. Setting it to any positive integer means that on failure connection is retried that many times e.g. setting it to 3 means total attempts to connect will be 4.

Possible values:

• Any integer value. 0 means connection is attempted only once

(Integer) Number of consecutive failed builds that result in disabling a compute service.

This option will cause nova-compute to set itself to a disabled state if a certain number of consecutive build failures occur. This will prevent the scheduler from continuing to send builds to a compute node that is consistently failing. Note that all failures qualify and count towards this score, including reschedules that may have been due to racy scheduler behavior. Since the failures must be consecutive, it is unlikely that occasional expected reschedules will actually disable a compute node.

Possible values:

• Any positive integer representing a build failure count.
• Zero to never auto-disable.

(String) Topic exchange name on which conductor nodes listen.

• Deprecated

  There is no need to let users choose the RPC topic for all services - there is little gain from this. Furthermore, it makes it really easy to break Nova by using this option.

(Integer) The lifetime of a console auth token.

A console auth token is used in authorizing console access for a user. Once the auth token time to live count has elapsed, the token is considered expired. Expired tokens are then deleted.

(List) Adds list of allowed origins to the console websocket proxy to allow connections from other origin hostnames. Websocket proxy matches the host header with the origin header to prevent cross-site requests. This list specifies if any there are values other than host are allowed in the origin header.

Possible values:

• A list where each element is an allowed origin hostnames, else an empty list

(String) Filename of root Certificate Revocation List (CRL). This is a list of certificates that have been revoked, and therefore, entities presenting those (revoked) certificates should no longer be trusted.

Related options:

• ca_path

(String) Filename of root CA (Certificate Authority). This is a container format and includes root certificates.

Possible values:

• Any file name containing root CA, cacert.pem is default

Related options:

• ca_path

(String) Filename of a private key.

Related options:

• keys_path

(String) Cipher-mode string to be used.

The cipher and mode to be used to encrypt ephemeral storage. The set of cipher-mode combinations available depends on kernel support. According to the dm-crypt documentation, the cipher is expected to be in the format: “<cipher>-<chainmode>-<ivmode>”.

Possible values:

• Any crypto option listed in /proc/crypto.

(Integer) Encryption key length in bits.

The bit length of the encryption key to be used to encrypt ephemeral storage. In XTS mode only half of the bits are used for encryption key.

(Boolean) Prevent non-isolated images from being built on isolated hosts.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect. Also note that this setting only affects scheduling if the ‘IsolatedHostsFilter’ filter is enabled. Even then, this option doesn’t affect the behavior of requests for isolated images, which will always be restricted to isolated hosts.

Related options:

• scheduler/isolated_images
• scheduler/isolated_hosts

(Integer) The number of instances that can be actively performing IO on a host.

Instances performing IO includes those in the following states: build, resize, snapshot, migrate, rescue, unshelve.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect. Also note that this setting only affects scheduling if the ‘io_ops_filter’ filter is enabled.

Possible values:

• An integer, where the integer corresponds to the max number of instances that can be actively performing IO on any given host.

(List) List of UUIDs for images that can only be run on certain hosts.

If there is a need to restrict some images to only run on certain designated hosts, list those image UUIDs here.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect. Also note that this setting only affects scheduling if the ‘IsolatedHostsFilter’ filter is enabled.

Possible values:

• A list of UUID strings, where each string corresponds to the UUID of an image

Related options:

• scheduler/isolated_hosts
• scheduler/restrict_isolated_hosts_to_isolated_images

(Integer) Maximum number of instances that be active on a host.

If you need to limit the number of instances on any given host, set this option to the maximum number of instances you want to allow. The num_instances_filter will reject any host that has at least as many instances as this option’s value.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect. Also note that this setting only affects scheduling if the ‘num_instances_filter’ filter is enabled.

Possible values:

• An integer, where the integer corresponds to the max instances that can be scheduled on a host.

(Floating point) IO operations weight multipler ratio.

This option determines how hosts with differing workloads are weighed. Negative values, such as the default, will result in the scheduler preferring hosts with lighter workloads whereas positive values will prefer hosts with heavier workloads. Another way to look at it is that positive values for this option will tend to schedule instances onto hosts that are already busy, while negative values will tend to distribute the workload across more hosts. The absolute value, whether positive or negative, controls how strong the io_ops weigher is relative to other weighers.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect. Also note that this setting only affects scheduling if the ‘io_ops’ weigher is enabled.

Possible values:

• An integer or float value, where the value corresponds to the multipler ratio for this weigher.

(List) List of hosts that can only run certain images.

If there is a need to restrict some images to only run on certain designated hosts, list those host names here.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect. Also note that this setting only affects scheduling if the ‘IsolatedHostsFilter’ filter is enabled.

Possible values:

• A list of strings, where each string corresponds to the name of a host

Related options:

• scheduler/isolated_images
• scheduler/restrict_isolated_hosts_to_isolated_images

(Floating point) Ram weight multipler ratio.

This option determines how hosts with more or less available RAM are weighed. A positive value will result in the scheduler preferring hosts with more available RAM, and a negative number will result in the scheduler preferring hosts with less available RAM. Another way to look at it is that positive values for this option will tend to spread instances across many hosts, while negative values will tend to fill up (stack) hosts as much as possible before scheduling to a less-used host. The absolute value, whether positive or negative, controls how strong the RAM weigher is relative to other weighers.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect. Also note that this setting only affects scheduling if the ‘ram’ weigher is enabled.

Possible values:

• An integer or float value, where the value corresponds to the multipler ratio for this weigher.

(Boolean) Enable baremetal filters.

Set this to True to tell the nova scheduler that it should use the filters specified in the ‘baremetal_scheduler_enabled_filters’ option. If you are not scheduling baremetal nodes, leave this at the default setting of False.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect.

Related options:

• If this option is set to True, then the filters specified in the ‘baremetal_scheduler_enabled_filters’ are used instead of the filters specified in ‘scheduler_enabled_filters’.

(List) Filters that the scheduler will use.

An ordered list of filter class names that will be used for filtering hosts. Ignore the word ‘default’ in the name of this option: these filters will always be applied, and they will be applied in the order they are listed so place your most restrictive filters first to make the filtering process more efficient.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect.

Possible values:

• A list of zero or more strings, where each string corresponds to the name of a filter to be used for selecting a host

Related options:

• All of the filters in this option must be present in the ‘scheduler_available_filters’ option, or a SchedulerHostFilterNotFound exception will be raised.

(List) Filters used for filtering baremetal hosts.

Filters are applied in order, so place your most restrictive filters first to make the filtering process more efficient.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect.

Possible values:

• A list of zero or more strings, where each string corresponds to the name of a filter to be used for selecting a baremetal host

Related options:

• If the ‘scheduler_use_baremetal_filters’ option is False, this option has no effect.

(Integer) Enable glance operation retries.

Specifies the number of retries when uploading / downloading an image to / from glance. 0 means no retries.

(List) List of url schemes that can be directly accessed.

This option specifies a list of url schemes that can be downloaded directly via the direct_url. This direct_URL can be fetched from Image metadata which can be used by nova to get the image more efficiently. nova-compute could benefit from this by invoking a copy when it has access to the same file system as glance.

Possible values:

• [file], Empty list (default)

(Boolean) Enable image signature verification.

nova uses the image signature metadata from glance and verifies the signature of a signed image while downloading that image. If the image signature cannot be verified or if the image signature metadata is either incomplete or unavailable, then nova will not boot the image and instead will place the instance into an error state. This provides end users with stronger assurances of the integrity of the image data they are using to create servers.

Related options:

• The options in the key_manager group, as the key_manager is used for the signature validation.

(Boolean) Enable/disables guestfs logging.

This configures guestfs to debug messages and push them to Openstack logging system. When set to True, it traces libguestfs API calls and enable verbose debug messages. In order to use the above feature, “libguestfs” package must be installed.

Related options: Since libguestfs access and modifies VM’s managed by libvirt, below options should be set to give access to those VM’s.

• libvirt.inject_key
• libvirt.inject_partition
• libvirt.inject_password

(String) The path to respond to healtcheck requests on.

• Deprecated

  No deprecation reason provided for this option.

(Boolean) Configuration drive cdrom

OpenStack can be configured to write instance metadata to a configuration drive, which is then attached to the instance before it boots. The configuration drive can be attached as a disk drive (default) or as a CD drive.

Possible values:

• True: Attach the configuration drive image as a CD drive.
• False: Attach the configuration drive image as a disk drive (Default).

Related options:

• This option is meaningful with force_config_drive option set to ‘True’ or when the REST API call to create an instance will have ‘–config-drive=True’ flag.
• config_drive_format option must be set to ‘iso9660’ in order to use CD drive as the configuration drive image.
• To use configuration drive with Hyper-V, you must set the mkisofs_cmd value to the full path to an mkisofs.exe installation. Additionally, you must set the qemu_img_cmd value to the full path to an qemu-img command installation.
• You can configure the Compute service to always create a configuration drive by setting the force_config_drive option to ‘True’.

(Integer) Volume attach retry count

The number of times to retry attaching a volume. Volume attachment is retried until success or the given retry count is reached.

Possible values:

• Positive integer values (Default: 10).

Related options:

• Time interval between attachment attempts is declared with volume_attach_retry_interval option.

(String) External virtual switch name

The Hyper-V Virtual Switch is a software-based layer-2 Ethernet network switch that is available with the installation of the Hyper-V server role. The switch includes programmatically managed and extensible capabilities to connect virtual machines to both virtual networks and the physical network. In addition, Hyper-V Virtual Switch provides policy enforcement for security, isolation, and service levels. The vSwitch represented by this config option must be an external one (not internal or private).

Possible values:

• If not provided, the first of a list of available vswitches is used. This list is queried using WQL.
• Virtual switch name.

(Integer) Power state event polling interval

Instance power state change event polling frequency. Sets the listener interval for power state events to the given value. This option enhances the internal lifecycle notifications of instances that reboot themselves. It is unlikely that an operator has to change this value.

Possible values:

• Time in seconds (Default: 2).

(Boolean) Enable instance metrics collection

Enables metrics collections for an instance by using Hyper-V’s metric APIs. Collected data can by retrieved by other apps and services, e.g.: Ceilometer.

(Integer) Power state check timeframe

The timeframe to be checked for instance power state changes. This option is used to fetch the state of the instance from Hyper-V through the WMI interface, within the specified timeframe.

Possible values:

• Timeframe in seconds (Default: 60).

(List) List of iSCSI initiators that will be used for estabilishing iSCSI sessions.

If none are specified, the Microsoft iSCSI initiator service will choose the initiator.

(Boolean) Configuration drive inject password

Enables setting the admin password in the configuration drive image.

Related options:

• This option is meaningful when used with other options that enable configuration drive usage with Hyper-V, such as force_config_drive.
• Currently, the only accepted config_drive_format is ‘iso9660’.

(Boolean) Use multipath connections when attaching iSCSI or FC disks.

This requires the Multipath IO Windows feature to be enabled. MPIO must be configured to claim such devices.

(Integer) The number of times to retry when a request conflicts. If set to 0, only try once, no retries.

Related options:

• api_retry_interval

(String) Fixed key returned by key manager, specified in hex.

Possible values:

• Empty string or a key in hex value

(String) Directory used to cache files related to PKI tokens. This option has been deprecated in the Ocata release and will be removed in the P release.

• Deprecated

  PKI token format is no longer supported.

(Integer) Determines the frequency at which the list of revoked tokens is retrieved from the Identity service (in seconds). A high number of revocation events combined with a low cache duration may significantly reduce performance. Only valid for PKI tokens. This option has been deprecated in the Ocata release and will be removed in the P release.

• Deprecated

  PKI token format is no longer supported.

(String) Mount options passed to the SMBFS client.

Provide SMBFS options as a single string containing all parameters. See mount.cifs man page for details. Note that the libvirt-qemu uid and gid must be specified.

(String) Live migration target URI to use.

Override the default libvirt live migration target URI (which is dependent on virt_type). Any included “%s” is replaced with the migration target hostname.

If this option is set to None (which is the default), Nova will automatically generate the live_migration_uri value based on only 3 supported virt_type in following list:

• ‘kvm’: ‘qemu+tcp://%s/system’
• ‘qemu’: ‘qemu+tcp://%s/system’
• ‘xen’: ‘xenmigr://%s/system’

Related options:

• live_migration_inbound_addr: If live_migration_inbound_addr value is not None, the ip/hostname address of target compute node is used instead of live_migration_uri as the uri for live migration.
• live_migration_scheme: If live_migration_uri is not set, the scheme used for live migration is taken from live_migration_scheme instead.

• Deprecated

  live_migration_uri is deprecated for removal in favor of two other options that allow to change live migration scheme and target URI: live_migration_scheme and live_migration_inbound_addr respectively.

(Boolean) Write a checksum for files in _base to disk

• Deprecated

  The image cache no longer periodically calculates checksums of stored images. Data integrity can be checked at the block or filesystem level.

(Integer) How frequently to checksum base images

• Deprecated

  The image cache no longer periodically calculates checksums of stored images. Data integrity can be checked at the block or filesystem level.

(Boolean) Allow the injection of an SSH key at boot time.

There is no agent needed within the image to do this. If libguestfs is available on the host, it will be used. Otherwise nbd is used. The file system of the image will be mounted and the SSH key, which is provided in the REST API call will be injected as SSH key for the root user and appended to the authorized_keys of that user. The SELinux context will be set if necessary. Be aware that the injection is not possible when the instance gets launched from a volume.

This config option will enable directly modifying the instance disk and does not affect what cloud-init may do using data from config_drive option or the metadata service.

Related options:

• inject_partition: That option will decide about the discovery and usage of the file system. It also can disable the injection at all.

(String) Discard option for nova managed disks.

Requires:

• Libvirt >= 1.0.6
• Qemu >= 1.5 (raw format)
• Qemu >= 1.6 (qcow2 format)

(String) Mount owner group name.

This option defines the owner group of Vzstorage cluster mountpoint.

Related options:

• vzstorage_mount_* group of parameters

(String) Overrides the default libvirt URI of the chosen virtualization type.

If set, Nova will use this URI to connect to libvirt.

Possible values:

• An URI like qemu:///system or xen+ssh://oirase/ for example. This is only necessary if the URI differs to the commonly known URIs for the chosen virtualization type.

Related options:

• virt_type: Influences what is used as default value here.

(String) Method used to wipe ephemeral disks when they are deleted. Only takes effect if LVM is set as backing storage.

Possible values:

• none - do not wipe deleted volumes
• zero - overwrite volumes with zeroes
• shred - overwrite volume repeatedly

Related options:

• images_type - must be set to lvm
• volume_clear_size

(Boolean) This option allows nova to switch an on-going live migration to post-copy mode, i.e., switch the active VM to the one on the destination node before the migration is complete, therefore ensuring an upper bound on the memory that needs to be transferred. Post-copy requires libvirt>=1.3.3 and QEMU>=2.5.0.

When permitted, post-copy mode will be automatically activated if a live-migration memory copy iteration does not make percentage increase of at least 10% over the last iteration.

The live-migration force complete API also uses post-copy when permitted. If post-copy mode is not available, force complete falls back to pausing the VM to ensure the live-migration operation will complete.

When using post-copy mode, if the source and destination hosts loose network connectivity, the VM being live-migrated will need to be rebooted. For more details, please see the Administration guide.

Related options:

• live_migration_permit_auto_converge

(String) Is used to set the CPU mode an instance should have.

If virt_type=”kvm|qemu”, it will default to “host-model”, otherwise it will default to “none”.

Possible values:

• host-model: Clones the host CPU feature flags.
• host-passthrough: Use the host CPU model exactly;
• custom: Use a named CPU model;
• none: Not set any CPU model.

Related options:

• cpu_model: If custom is used for cpu_mode, set this config option too, otherwise this would result in an error and the instance won’t be launched.

(String) Determine the snapshot image format when sending to the image service.

If set, this decides what format is used when sending the snapshot to the image service. If not set, defaults to same type as source image.

Possible values:

• raw: RAW disk format
• qcow2: KVM default disk format
• vmdk: VMWare default disk format
• vdi: VirtualBox default disk format
• If not set, defaults to same type as source image.

(String) Schema used for live migration.

Override the default libvirt live migration scheme (which is dependent on virt_type). If this option is set to None, nova will automatically choose a sensible default based on the hypervisor. It is not recommended that you change this unless you are very sure that hypervisor supports a particular scheme.

Related options:

• virt_type: This option is meaningful only when virt_type is set to kvm or qemu.
• live_migration_uri: If live_migration_uri value is not None, the scheme used for live migration is taken from live_migration_uri instead.

(String) Path to the SSD cache file.

You can attach an SSD drive to a client and configure the drive to store a local cache of frequently accessed data. By having a local cache on a client’s SSD drive, you can increase the overall cluster performance by up to 10 and more times. WARNING! There is a lot of SSD models which are not server grade and may loose arbitrary set of data changes on power loss. Such SSDs should not be used in Vstorage and are dangerous as may lead to data corruptions and inconsistencies. Please consult with the manual on which SSD models are known to be safe or verify it using vstorage-hwflush-check(1) utility.

This option defines the path which should include “%(cluster_name)s” template to separate caches from multiple shares.

Related options:

• vzstorage_mount_opts may include more detailed cache options.

(List) Specific cache modes to use for different disk types.

For example: file=directsync,block=none,network=writeback

For local or direct-attached storage, it is recommended that you use writethrough (default) mode, as it ensures data integrity and has acceptable I/O performance for applications running in the guest, especially for read operations. However, caching mode none is recommended for remote NFS storage, because direct I/O operations (O_DIRECT) perform better than synchronous I/O operations (with O_SYNC). Caching mode none effectively turns all guest I/O operations into direct I/O operations on the host, which is the NFS client in this environment.

Possible cache modes:

• default: Same as writethrough.
• none: With caching mode set to none, the host page cache is disabled, but the disk write cache is enabled for the guest. In this mode, the write performance in the guest is optimal because write operations bypass the host page cache and go directly to the disk write cache. If the disk write cache is battery-backed, or if the applications or storage stack in the guest transfer data properly (either through fsync operations or file system barriers), then data integrity can be ensured. However, because the host page cache is disabled, the read performance in the guest would not be as good as in the modes where the host page cache is enabled, such as writethrough mode.
• writethrough: writethrough mode is the default caching mode. With caching set to writethrough mode, the host page cache is enabled, but the disk write cache is disabled for the guest. Consequently, this caching mode ensures data integrity even if the applications and storage stack in the guest do not transfer data to permanent storage properly (either through fsync operations or file system barriers). Because the host page cache is enabled in this mode, the read performance for applications running in the guest is generally better. However, the write performance might be reduced because the disk write cache is disabled.
• writeback: With caching set to writeback mode, both the host page cache and the disk write cache are enabled for the guest. Because of this, the I/O performance for applications running in the guest is good, but the data is not protected in a power failure. As a result, this caching mode is recommended only for temporary data where potential data loss is not a concern.
• directsync: Like “writethrough”, but it bypasses the host page cache.
• unsafe: Caching mode of unsafe ignores cache transfer operations completely. As its name implies, this caching mode should be used only for temporary data where data loss is not a concern. This mode can be useful for speeding up guest installations, but you should switch to another caching mode in production environments.

(String) Directory where the NFS volume is mounted on the compute node. The default is ‘mnt’ directory of the location where nova’s Python module is installed.

NFS provides shared storage for the OpenStack Block Storage service.

Possible values:

• A string representing absolute path of mount point.

(Boolean) Enable a mouse cursor within a graphical VNC or SPICE sessions.

This will only be taken into account if the VM is fully virtualized and VNC and/or SPICE is enabled. If the node doesn’t support a graphical framebuffer, then it is valid to set this to False.

Related options:

• [vnc]enabled: If VNC is enabled, use_usb_tablet will have an effect.
• [spice]enabled + [spice].agent_enabled: If SPICE is enabled and the spice agent is disabled, the config value of use_usb_tablet will have an effect.

• Deprecated

  This option is being replaced by the ‘pointer_model’ option.

(String) The RADOS client name for accessing rbd(RADOS Block Devices) volumes.

Libvirt will refer to this user when connecting and authenticating with the Ceph RBD server.

(String) Directory where the Virtuozzo Storage clusters are mounted on the compute node.

This option defines non-standard mountpoint for Vzstorage cluster.

Related options:

• vzstorage_mount_* group of parameters

(String) libvirt’s transport method for remote file operations.

Because libvirt cannot use RPC to copy files over network to/from other compute nodes, other method must be used for:

• creating directory on remote host
• creating file on remote host
• removing file from remote host
• copying file to remote host

(String) Override the default disk prefix for the devices attached to an instance.

If set, this is used to identify a free disk device name for a bus.

Possible values:

• Any prefix which will result in a valid disk device name like ‘sda’ or ‘hda’ for example. This is only necessary if the device names differ to the commonly known device name prefixes for a virtualization type such as: sd, xvd, uvd, vd.

Related options:

• virt_type: Influences which device type is used, which determines the default disk prefix.

(String) The iSCSI transport iface to use to connect to target in case offload support is desired.

Default format is of the form <transport_name>.<hwaddress> where <transport_name> is one of (be2iscsi, bnx2i, cxgb3i, cxgb4i, qla4xxx, ocs) and <hwaddress> is the MAC address of the interface and can be generated via the iscsiadm -m iface command. Do not confuse the iscsi_iface parameter to be provided here with the actual transport name.

(String) Allows image information files to be stored in non-standard locations

• Deprecated

  Image info files are no longer used by the image cache

(Integer) Number of times to scan iSER target to find volume.

iSER is a server network protocol that extends iSCSI protocol to use Remote Direct Memory Access (RDMA). This option allows the user to specify the maximum number of scan attempts that can be made to find iSER volume.

(String) The ID of the RAM disk (ARI) image to use with the rescue image.

If the chosen rescue image allows the separate definition of its RAM disk, the value of this option is used, if specified. This is the case when Amazon‘s AMI/AKI/ARI image format is used for the rescue image.

Possible values:

• An ID of a RAM disk image or nothing. If nothing is specified, the RAM disk from the instance is used if it was launched with one.

Related options:

• rescue_image_id: If that option points to an image in Amazon‘s AMI/AKI/ARI image format, it’s useful to use rescue_ramdisk_id too.

(String) Base dir where Scality SOFS shall be mounted.

The Scality volume driver in Nova mounts SOFS and lets the hypervisor access the volumes.

Possible values:

• $state_path/scality where state_path is a config option that specifies the top-level directory for maintaining nova’s state or Any string containing the full directory path.

(Integer) Time to wait, in seconds, for migration to successfully complete transferring data before aborting the operation.

Value is per GiB of guest RAM + disk to be transferred, with lower bound of a minimum of 2 GiB. Should usually be larger than downtime delay * downtime steps. Set to 0 to disable timeouts.

Related options:

• live_migration_downtime
• live_migration_downtime_steps
• live_migration_downtime_delay

• Mutable

  This option can be changed without restarting.

(String) Host to locate redis.

• Deprecated

  Replaced by [DEFAULT]/transport_url

(String) Password for Redis server (optional).

• Deprecated

  Replaced by [DEFAULT]/transport_url

(Boolean) This setting determines how any unavailable metrics are treated. If this option is set to True, any hosts for which a metric is unavailable will raise an exception, so it is recommended to also use the MetricFilter to filter out those hosts before weighing.

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect.

Possible values:

• True or False, where False ensures any metric being unavailable for a host will set the host weight to ‘weight_of_unavailable’.

Related options:

• weight_of_unavailable

(Floating point) When any of the following conditions are met, this value will be used in place of any actual metric value:

• One of the metrics named in ‘weight_setting’ is not available for a host, and the value of ‘required’ is False
• The ratio specified for a metric in ‘weight_setting’ is 0
• The ‘weight_multiplier’ option is set to 0

This option is only used by the FilterScheduler and its subclasses; if you use a different scheduler, this option has no effect.

Possible values:

• An integer or float value, where the value corresponds to the multipler ratio for this weigher.

Related options:

• weight_setting
• required
• weight_multiplier

(String) Location of MKS web console proxy

The URL in the response points to a WebMKS proxy which starts proxying between client and corresponding vCenter server where instance runs. In order to use the web based console access, WebMKS proxy should be installed and configured

Possible values:

• Must be a valid URL of the form:http://host:port/

(String) Default name for the floating IP pool.

Specifies the name of floating IP pool used for allocating floating IPs. This option is only used if Neutron does not specify the floating IP pool name in port binding reponses.

(Boolean) When set to True, this option indicates that Neutron will be used to proxy metadata requests and resolve instance ids. Otherwise, the instance ID must be passed to the metadata request in the ‘X-Instance-ID’ header.

Related options:

• metadata_proxy_shared_secret

(URI) This option specifies the URL for connecting to Neutron.

Possible values:

• Any valid URL that points to the Neutron API service is appropriate here. This typically matches the URL returned for the ‘network’ service type from the Keystone service catalog.

(String) Default name for the Open vSwitch integration bridge.

Specifies the name of an integration bridge interface used by OpenvSwitch. This option is only used if Neutron does not specify the OVS bridge name in port binding responses.

(String) If set, send compute.instance.update notifications on instance state changes.

Please refer to https://wiki.openstack.org/wiki/SystemUsageData for additional information on notifications.

Possible values:

• None - no notifications
• “vm_state” - notifications on VM state changes
• “vm_and_task_state” - notifications on VM and task state changes

(String) Default publisher_id for outgoing notifications. If you consider routing notifications using different publisher, change this value accordingly.

Possible values:

• Defaults to the IPv4 address of this host, but it can be any valid oslo.messaging publisher_id

Related options:

• my_ip - IP address of this host

(String) This option is a string representing a regular expression (regex) that matches the project_id as contained in URLs. If not set, it will match normal UUIDs created by keystone.

Possible values:

• A string representing any legal regular expression

• Deprecated

  Recent versions of nova constrain project IDs to hexadecimal characters and dashes. If your installation uses IDs outside of this range, you should use this option to provide your own regex and give you time to migrate offending projects to valid IDs before the next release.

(Boolean) Accept clients using either SSL or plain TCP

• Deprecated

  Not applicable - not a SSL server

(String) Password for message broker authentication

• Deprecated

  Should use configuration option transport_url to provide the password.