diff --git a/README.md b/README.md index a21aedf8..7e18332e 100644 --- a/README.md +++ b/README.md @@ -1,15 +1,15 @@ # Overview -This charm provides the Glance image service for OpenStack. It is intended to -be used alongside the other OpenStack components. +The glance charm provides the Glance image service for OpenStack. It is +intended to be used alongside the other OpenStack components. # 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. +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. ## Local Storage @@ -23,9 +23,9 @@ to store image data: ## Swift backed storage -Glance can also use Swift Object storage for image storage. Swift is often +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 +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: @@ -40,21 +40,21 @@ 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 +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 + 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 the relevant section below). +> **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 @@ -84,11 +84,13 @@ e.g. juju add-relation glance ceilometer-agent ... -## Spaces +## Network spaces -This charm supports the use of Juju Spaces, allowing the charm to be bound to -network space configurations managed directly by Juju. This is only supported -with Juju 2.0 and above. +This charm supports the use of Juju [network spaces][juju-docs-spaces]. This +feature optionally allows specific types of the application's network traffic +to be bound to subnets that the underlying hardware is connected to. + +> **Note**: Spaces must be configured in the backing cloud prior to deployment. API endpoints can be bound to distinct network spaces supporting the network separation of public, internal and admin endpoints. @@ -125,19 +127,16 @@ configuration: ceph: ceph-access-space ``` -NOTE: Spaces must be configured in the underlying provider prior to attempting -to use them. +> **Note**: Existing glance units configured with the `os-admin-network`, + `os-internal-network`, or `os-public-network` options will continue to honour + them. Furthermore, these options override any space bindings, if set. -NOTE: Existing deployments using os-*-network configuration options will -continue to function; these options are preferred over any network space -binding provided if set. +## Policy overrides -## Policy Overrides - -Policy overrides is an **advanced** feature that allows an operator to override -the default policy of an OpenStack service. The policies that the service -supports, the defaults it implements in its code, and the defaults that a charm -may include should all be clearly understood before proceeding. +Policy overrides is an advanced feature that allows an operator to override the +default policy of an OpenStack service. The policies that the service supports, +the defaults it implements in its code, and the defaults that a charm may +include should all be clearly understood before proceeding. > **Caution**: It is possible to break the system (for tenants and other services) if policies are incorrectly applied to the service. @@ -152,14 +151,14 @@ 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 +See appendix [Policy overrides][cdg-appendix-n] in the [OpenStack Charms Deployment Guide][cdg] for a thorough treatment of this feature. # Bugs Please report bugs on [Launchpad][lp-bugs-charm-glance]. -For general charm questions refer to the OpenStack [Charm Guide][cg]. +For general charm questions refer to the [OpenStack Charm Guide][cg]. @@ -169,3 +168,4 @@ For general charm questions refer to the OpenStack [Charm Guide][cg]. [lp-bugs-charm-glance]: https://bugs.launchpad.net/charm-glance/+filebug [hacluster-charm]: https://jaas.ai/hacluster [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