nova/doc/source/admin/flavors2.rst

==============
Manage flavors
==============

.. todo:: Merge this into 'flavors'

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
   :doc:`flavors`.

A flavor consists of the following parameters:

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

Name
  Name for the new flavor.

VCPUs
  Number of virtual CPUs to use.

Memory MB
  Amount of RAM to use (in megabytes).

Root Disk GB
  Amount of disk space (in gigabytes) to use for the root (``/``) partition.

Ephemeral Disk GB
  Amount of disk space (in gigabytes) to use for the ephemeral partition. If
  unspecified, the value is ``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.

Swap
  Amount of swap space (in megabytes) to use. If unspecified, the value is
  ``0`` by default.

RXTX Factor
  Optional property that allows servers with a different bandwidth be created
  with the RXTX Factor. The default value is ``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.

Is Public
  Boolean value defines whether the flavor is available to all users.  Defaults
  to ``True``.

Extra Specs
  Key and value pairs that define on which compute nodes a flavor can run.
  These pairs must match corresponding pairs on the compute nodes. It can be
  used to implement special resources, such as flavors that run on only compute
  nodes with GPU hardware.

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 :command:`openstack flavor` commands
provided by the ``python-openstackclient`` package.

Create a flavor
~~~~~~~~~~~~~~~

#. 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:

   .. code-block:: console

      $ 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:

   .. code-block:: console

      $ 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):

   .. code-block:: console

      $ 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
   <https://docs.openstack.org/ops-guide/ops-user-facing-operations.html#private-flavors>`_.

   For a list of optional parameters, run this command:

   .. code-block:: console

      $ 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:

   .. code-block:: console

      $ 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 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 :doc:`flavors`.

   For a list of optional parameters, run this command:

   .. code-block:: console

      $ nova help flavor-key

Delete a flavor
~~~~~~~~~~~~~~~

Delete a specified flavor, as follows:

.. code-block:: console

   $ openstack flavor delete FLAVOR_ID