In OpenStack, flavors define the compute, memory, and
storage capacity of nova computing instances. To put it
simply, a flavor is an available hardware configuration for a
server. It defines the size
of a virtual server
that can be launched.
Note
Flavors can also determine on which compute host a flavor can be used to launch an instance. For information about customizing flavors, refer to Flavors.
A flavor consists of the following parameters:
0
by default.
Ephemeral disks offer machine local disk storage
linked to the lifecycle of a VM instance. When a
VM is terminated, all data on the ephemeral disk
is lost. Ephemeral disks are not included in any
snapshots.0
by default.1.0
. That is,
the new bandwidth is the same as that of the attached network. The
RXTX Factor is available only for Xen or NSX based systems.True
.As of Newton, there are no default flavors. 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 |
You can create and manage flavors with the
openstack flavor commands provided by the python-openstackclient
package.
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
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
Note
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
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. See Private Flavors in the OpenStack Operations Guide.
For a list of optional parameters, run this command:
$ openstack help flavor create
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
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 LTE 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
Flavors.
For a list of optional parameters, run this command:
$ nova help flavor-key
Except where otherwise noted, this document is licensed under Creative Commons Attribution 3.0 License. See all OpenStack Legal Documents.