Glance - Image service¶

Overview¶

Glance can be deployed using Kolla and supports the following backends:

• file
• ceph
• vmware
• swift

File backend¶

When using the file backend, images will be stored locally under the value of the glance_file_datadir_volume variable, which defaults to a docker volume called glance. By default when using file backend only one glance-api container can be running.

For better reliability and performance, glance_file_datadir_volume should be mounted under a shared filesystem such as NFS.

Usage of glance file backend under shared filesystem:

glance_backend_file: "yes"
glance_file_datadir_volume: "/path/to/shared/storage/"

Ceph backend¶

To make use of ceph backend in glance, simply enable ceph or external ceph. By default will enable backend ceph automatically. Please refer to Ceph - Software Defined Storage (Deprecated) or External Ceph on how to configure this backend.

To enable the ceph backend manually:

glance_backend_ceph: "yes"

VMware backend¶

To make use of VMware datastores as a glance backend, enable glance_backend_vmware and refer to VMware for further VMware configuration.

To enable the vmware backend manually:

glance_backend_vmware: "yes"

Swift backend¶

To store glance images in a swift cluster, the swift backend should be enabled. Refer to Swift- Object storage service on how to configure swift in kolla. If ceph is enabled, will have higher precedence over swift as glance backend.

To enable the swift backend manually:

glance_backend_swift: "yes"

Overview¶

Glance can be upgraded with the following methods:

• Rolling upgrade
• Legacy upgrade

Rolling upgrade¶

As of the Rocky release, glance can be upgraded in a rolling upgrade mode. This mode will reduce the API downtime during upgrade to a minimum of a container restart, aiming for zero downtime in future releases.

By default it is disabled, so if you want to upgrade using this mode it will need to be enabled.

glance_enable_rolling_upgrade: "yes"

Legacy upgrade¶

This upgrade method will stop APIs during database schema migrations, and container restarts.

It is the default mode, ensure rolling upgrade method is not enabled.

glance_enable_rolling_upgrade: "no"

Glance cache¶

Glance cache is disabled by default, it can be enabled by:

enable_glance_image_cache: "yes"
glance_cache_max_size: "10737418240" # 10GB by default

Glance caches are not cleaned up automatically, the glance team recommends to use a cron service to regularly clean cached images. In the future kolla will deploy a cron container to manage such clean ups. Please refer to Glance image cache.