In OpenStack the base operating system is usually copied from an image stored in the OpenStack Image Service. This is the most common case and results in an ephemeral instance that starts from a known template state and loses all accumulated states on shutdown. It is also possible to put an operating system on a persistent volume in the Nova-Volume or Cinder volume system. This gives a more traditional persistent system that accumulates states, which are preserved across restarts. To get a list of available images on your system run:
$ nova image-list +--------------------------------------+-------------------------------+--------+--------------------------------------+ | ID | Name | Status | Server | +--------------------------------------+-------------------------------+--------+--------------------------------------+ | aee1d242-730f-431f-88c1-87630c0f07ba | Ubuntu 12.04 cloudimg amd64 | ACTIVE | | | 0b27baa1-0ca6-49a7-b3f4-48388e440245 | Ubuntu 12.10 cloudimg amd64 | ACTIVE | | | df8d56fc-9cea-4dfd-a8d3-28764de3cb08 | jenkins | ACTIVE | | +--------------------------------------+-------------------------------+--------+--------------------------------------+
The displayed image attributes are:
IDAutomatically generated UUID of the image
NameFree form, human-readable name for image
StatusThe status of the image. Images marked
ACTIVEare available for use.ServerFor images that are created as snapshots of running instances, this is the UUID of the instance the snapshot derives from. For uploaded images, this field is blank.
Virtual hardware templates are called
flavors. The default installation
provides five flavors. By default, these are configurable
by admin users, however that behavior can be changed by
redefining the access controls for
compute_extension:flavormanage
in /etc/nova/policy.json on the
compute-api server.
For a list of flavors that are available on your system:
$ nova flavor-list +----+-----------+-----------+------+-----------+------+-------+-------------+ | ID | Name | Memory_MB | Disk | Ephemeral | Swap | VCPUs | RXTX_Factor | +----+-----------+-----------+------+-----------+------+-------+-------------+ | 1 | m1.tiny | 512 | 1 | N/A | 0 | 1 | | | 2 | m1.small | 2048 | 20 | N/A | 0 | 1 | | | 3 | m1.medium | 4096 | 40 | N/A | 0 | 2 | | | 4 | m1.large | 8192 | 80 | N/A | 0 | 4 | | | 5 | m1.xlarge | 16384 | 160 | N/A | 0 | 8 | | +----+-----------+-----------+------+-----------+------+-------+-------------+
