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# Overview
The glance charm provides the Glance image service for OpenStack. It is
intended to be used alongside the other OpenStack components.
The glance charm deploys [Glance][upstream-glance], the core OpenStack service
that acts as the central repository for virtual machine (VM) images. The charm
works alongside other Juju-deployed OpenStack services.
# Usage
Glance may be deployed in a number of ways. This charm focuses on 3 main
configurations. All require the existence of the other core OpenStack services
deployed via Juju charms, specifically: mysql, keystone and
nova-cloud-controller. The following assumes these services have already been
deployed.
## Configuration
This section covers common and/or important configuration options. See file
@ -21,7 +16,7 @@ on configuring applications.
#### `openstack-origin`
The `openstack-origin` option states the software sources. A common value is an
OpenStack UCA release (e.g. 'cloud:xenial-queens' or 'cloud:bionic-ussuri').
OpenStack UCA release (e.g. 'cloud:bionic-ussuri' or 'cloud:focal-victoria').
See [Ubuntu Cloud Archive][wiki-uca]. The underlying host's existing apt
sources will be used if this option is not specified (this behaviour can be
explicitly chosen by using the value of 'distro').
@ -31,6 +26,83 @@ explicitly chosen by using the value of 'distro').
The `pool-type` option dictates the Ceph storage pool type. See sections 'Ceph
pool type' and 'Ceph backed storage' for more information.
## Deployment
This section includes three different deployment scenarios, each of which
requires these applications to be present: keystone, nova-cloud-controller,
nova-compute, and a cloud database.
The database application is determined by the series. Prior to focal
[percona-cluster][percona-cluster-charm] is used, otherwise it is
[mysql-innodb-cluster][mysql-innodb-cluster-charm]. In the example deployment
below mysql-innodb-cluster has been chosen.
### Ceph-backed storage
Ceph is the recommended storage backend solution for Glance. The steps below
assume a pre-existing Ceph cluster (see the [ceph-mon][ceph-mon-charm] and
[ceph-osd][ceph-osd-charm] charms).
Here, Glance is deployed to a container on machine '1' and related to the Ceph
cluster via the ceph-mon charm:
juju deploy --to lxd:1 glance
juju add-relation glance:ceph ceph-mon:client
Proceed with a group of commands common to all three scenarios:
juju add-relation glance:identity-service keystone:identity-service
juju add-relation glance:image-service nova-cloud-controller:image-service
juju add-relation glance:image-service nova-compute:image-service
juju deploy mysql-router glance-mysql-router
juju add-relation glance-mysql-router:db-router mysql-innodb-cluster:db-router
juju add-relation glance-mysql-router:shared-db glance:shared-db
This configuration can be used to support Glance in HA/scale-out deployments.
> **Note**: In this scenario Glance acts as a Ceph client, which requires
L3 network connectivity to Ceph monitors and OSDs. For MAAS-based deployments
this can be addressed with network spaces (see section 'Network spaces'
below).
### Swift-backed storage
Glance can use OpenStack Swift as its storage backend. The steps below assume a
pre-existing Swift deployment (see the [swift-proxy][swift-proxy-charm] and
[swift-storage][swift-storage-charm] charms).
Here, Glance is deployed to a container on machine '1' and related to Swift
via the swift-proxy charm:
juju deploy --to lxd:1 glance
juju add-relation glance:object-store swift-proxy:object-store
Proceed with the common group of commands from the Ceph scenario.
This configuration can be used to support Glance in HA/scale-out deployments.
### Local storage
Glance can simply use the storage available on the application unit's machine
to store image data:
juju deploy --to lxd:1 glance
Proceed with the common group of commands from the Ceph scenario.
## Actions
This section covers Juju [actions][juju-docs-actions] supported by the charm.
Actions allow specific operations to be performed on a per-unit basis. To
display action descriptions run `juju actions glance`. If the charm is not
deployed then see file `actions.yaml`.
* `openstack-upgrade`
* `pause`
* `resume`
* `security-checklist`
## Ceph pool type
Ceph storage pools can be configured to ensure data resiliency either through
@ -96,51 +168,6 @@ the compression behaviour.
> **Note**: BlueStore compression is supported starting with Ceph Mimic.
## Local Storage
In this configuration, Glance uses the local storage available on the server
to store image data:
juju deploy glance
juju add-relation glance keystone
juju add-relation glance mysql
juju add-relation glance nova-cloud-controller
## Swift backed storage
Glance can also use Swift Object storage for image storage. Swift is often
deployed as part of an OpenStack cloud and provides increased resilience and
scale when compared to using local disk storage. This configuration assumes
that you have already deployed Swift using the swift-proxy and swift-storage
charms:
juju deploy glance
juju add-relation glance keystone
juju add-relation glance mysql
juju add-relation glance nova-cloud-controller
juju add-relation glance swift-proxy
This configuration can be used to support Glance in HA/Scale-out deployments.
## Ceph backed storage
In this configuration, Glance uses Ceph based object storage to provide
scalable, resilient storage of images. This configuration assumes that you
have already deployed Ceph using the ceph charm:
juju deploy glance
juju add-relation glance keystone
juju add-relation glance mysql
juju add-relation glance nova-cloud-controller
juju add-relation glance ceph-mon
This configuration can also be used to support Glance in HA/Scale-out
deployments.
> **Note**: Glance acts as a Ceph client in this case which requires IP (L3)
connectivity to Ceph monitors and OSDs. For MAAS-based deployments this can
be addressed with network spaces (see section 'Network spaces' below).
## High availability
When more than one unit is deployed with the [hacluster][hacluster-charm]
@ -158,16 +185,16 @@ Deployment Guide][cdg] for details.
## Glance metering
In order to do Glance metering with Ceilometer, an AMQP relation is required
e.g.
Glance metering can be achieved with Ceilometer. The
[rabbitmq-server][rabbitmq-server-charm] and
[ceilometer-agent][ceilometer-agent-charm] applications are required to be
present.
juju deploy glance
juju deploy rabbitmq-server
juju deploy ceilometer-agent
...
juju add-relation glance rabbitmq-server
juju add-relation glance ceilometer-agent
...
Assuming Glance is deployed, add two relations:
juju add-relation glance:amqp rabbitmq-server:amqp
juju add-relation glance:amqp ceilometer-agent:amqp
juju add-relation glance:juju-info ceilometer-agent:container
## Network spaces
@ -236,8 +263,8 @@ Here are the essential commands (filenames are arbitrary):
juju attach-resource glance policyd-override=overrides.zip
juju config glance use-policyd-override=true
See appendix [Policy overrides][cdg-appendix-n] in the [OpenStack Charms
Deployment Guide][cdg] for a thorough treatment of this feature.
See [Policy overrides][cdg-appendix-n] in the [OpenStack Charms Deployment
Guide][cdg] for a thorough treatment of this feature.
# Bugs
@ -252,9 +279,19 @@ For general charm questions refer to the [OpenStack Charm Guide][cg].
[cdg-appendix-n]: https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/app-policy-overrides.html
[lp-bugs-charm-glance]: https://bugs.launchpad.net/charm-glance/+filebug
[hacluster-charm]: https://jaas.ai/hacluster
[ceph-mon-charm]: https://jaas.ai/ceph-mon
[ceph-osd-charm]: https://jaas.ai/ceph-osd
[swift-proxy-charm]: https://jaas.ai/swift-proxy
[swift-storage-charm]: https://jaas.ai/swift-storage
[percona-cluster-charm]: https://jaas.ai/percona-cluster
[mysql-innodb-cluster-charm]: https://jaas.ai/mysql-innodb-cluster
[rabbitmq-server-charm]: https://jaas.ai/rabbitmq-server
[ceilometer-agent-charm]: https://jaas.ai/ceilometer-agent
[cdg-ha-apps]: https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/app-ha.html#ha-applications
[juju-docs-spaces]: https://juju.is/docs/spaces
[wiki-uca]: https://wiki.ubuntu.com/OpenStack/CloudArchive
[juju-docs-config-apps]: https://juju.is/docs/configuring-applications
[cdg-ceph-erasure-coding]: https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/app-erasure-coding.html
[ceph-bluestore-compression]: https://docs.ceph.com/en/latest/rados/configuration/bluestore-config-ref/#inline-compression
[upstream-glance]: https://docs.openstack.org/glance/latest/
[juju-docs-actions]: https://jaas.ai/docs/actions