Restrict the Image Library Service to a Specific Cluster

Overview

By default, the Image Library Service operates at the region level: the Compute Service and the Persistent Storage Service round robin across all Image Library hosts in the region to fetch an image. In a multi-cluster deployment, you may want the hosts in a cluster to use only that cluster's Image Library host, for isolation and better performance. Private Cloud Director does not expose a blueprint-level setting for this, so you restrict it with a per-host configuration override.

In this guide, you will apply a configuration override on the compute and persistent storage hosts in a cluster so that they fetch images only from that cluster's Image Library host.

Important

This is an advanced operation that should only be performed by Administrators, ideally under guidance from the Platform9 support or solution architect teams.

Before You Begin

• Apply the override on every compute host and every persistent storage host in the target cluster. If you miss a host, it continues to fetch images from any Image Library host in the region.
• Changes persist across upgrades and require a service restart to take effect.
• Identify the cluster-local Image Library endpoint first, in the form https://<image-library-host>:9494. Use https://localhost:9494 only when the host you are editing also has the Image Library role assigned.

Apply the Override

On each compute host and each persistent storage host in the cluster, add the following block to the service's override file:

Bash

[glance]
endpoint_override = https://localhost:9494

[pf9_glance]
glance_cluster = false

• endpoint_override sets the single Image Library endpoint this host uses. Replace https://localhost:9494 with the cluster-local endpoint (https://<image-library-host>:9494) on any host that does not also hold the Image Library role.
• glance_cluster = false disables the default region-wide behavior, so the service does not round robin to other Image Library hosts.

The Compute Service reads this override when booting a VM from an image, and the Persistent Storage Service reads it when creating a volume from an image. Add the block to both override files and restart the corresponding service:

Service	Override file	Restart command
Compute	/opt/pf9/etc/nova/conf.d/nova_override.conf	systemctl restart pf9-ostackhost
Persistent Storage	/opt/pf9/etc/pf9-cindervolume-base/conf.d/cinder_override.conf	sudo service pf9-cindervolume-base restart

Verify the Configuration

Create a test VM, and a test volume from an image, in the cluster. Confirm that both are served by the cluster-local Image Library host, for example by checking /var/log/pf9/glance-api.log on that host.