Manage Flavors

Manage Flavors

Admin users can use the openstack flavor command to customize and manage flavors. To see information for this command, run:

$ openstack flavor --help
Command "flavor" matches:
  flavor create
  flavor delete
  flavor list
  flavor set
  flavor show
  flavor unset


Configuration rights can be delegated to additional users by redefining the access controls for os_compute_api:os-flavor-manage in /etc/nova/policy.json on the nova-api server.


Flavor customization can be limited by the hypervisor in use. For example the libvirt driver enables quotas on CPUs available to a VM, disk tuning, bandwidth I/O, watchdog behavior, random number generator device control, and instance VIF traffic control.

For information on the flavors and flavor extra specs, refer to Flavors.

Create a flavor

  1. List flavors to show the ID and name, the amount of memory, the amount of disk space for the root partition and for the ephemeral partition, the swap, and the number of virtual CPUs for each flavor:

    $ openstack flavor list
  2. To create a flavor, specify a name, ID, RAM size, disk size, and the number of vCPUs for the flavor, as follows:

    $ openstack flavor create FLAVOR_NAME --id FLAVOR_ID \
        --ram RAM_IN_MB --disk ROOT_DISK_IN_GB --vcpus NUMBER_OF_VCPUS


    Unique ID (integer or UUID) for the new flavor. If specifying 'auto', a UUID will be automatically generated.

    Here is an example with additional optional parameters filled in that creates a public extra_tiny flavor that automatically gets an ID assigned, with 256 MB memory, no disk space, and one VCPU. The rxtx-factor indicates the slice of bandwidth that the instances with this flavor can use (through the Virtual Interface (vif) creation in the hypervisor):

    $ openstack flavor create --public m1.extra_tiny --id auto \
        --ram 256 --disk 0 --vcpus 1 --rxtx-factor 1
  3. If an individual user or group of users needs a custom flavor that you do not want other projects to have access to, you can change the flavor's access to make it a private flavor.


    Add an example of how to do this

    For a list of optional parameters, run this command:

    $ openstack help flavor create


This should be migrated to the 'openstack' tool

  1. After you create a flavor, assign it to a project by specifying the flavor name or ID and the project ID:

    $ nova flavor-access-add FLAVOR TENANT_ID
  2. In addition, you can set or unset extra_spec for the existing flavor. The extra_spec metadata keys can influence the instance directly when it is launched. If a flavor sets the extra_spec key/value quota:vif_outbound_peak=65536, the instance's outbound peak bandwidth I/O should be less than or equal to 512 Mbps. There are several aspects that can work for an instance including CPU limits, Disk tuning, Bandwidth I/O, Watchdog behavior, and Random-number generator. For information about supporting metadata keys, see Manage Flavors.

    For a list of optional parameters, run this command:

    $ nova help flavor-key

Modify a flavor

Delete a flavor

Delete a specified flavor, as follows:

$ openstack flavor delete FLAVOR_ID

Default Flavors

Previous versions of nova typically deployed with default flavors. This was removed from Newton. The following table lists the default flavors for Mitaka and earlier.

Flavor VCPUs Disk (in GB) RAM (in MB)
m1.tiny 1 1 512
m1.small 1 20 2048
m1.medium 2 40 4096
m1.large 4 80 8192
m1.xlarge 8 160 16384
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