Highly available Image API

The OpenStack Image service offers a service for discovering, registering, and retrieving virtual machine images. To make the OpenStack Image API service highly available in active/passive mode, you must:

Prerequisites

Before beginning, ensure that you are familiar with the documentation for installing the OpenStack Image API service. See the Image service section in the Installation Guides, depending on your distribution.

Add OpenStack Image API resource to Pacemaker

  1. Download the resource agent to your system:

    # cd /usr/lib/ocf/resource.d/openstack
# wget https://opendev.org/x/openstack-resource-agents/raw/branch/master/ocf/glance-api
# chmod a+rx *

  2. Add the Pacemaker configuration for the OpenStack Image API resource. Use the following command to connect to the Pacemaker cluster:

    crm configure

    Note

    The crm configure command supports batch input. Copy and paste the lines in the next step into your live Pacemaker configuration and then make changes as required.

    For example, you may enter edit p_ip_glance-api from the crm configure menu and edit the resource to match your preferred virtual IP address.

  3. Add the following cluster resources:

    primitive p_glance-api ocf:openstack:glance-api \
  params config="/etc/glance/glance-api.conf" \
  os_password="secretsecret" \
  os_username="admin" os_tenant_name="admin" \
  os_auth_url="http://10.0.0.11:5000/v2.0/" \
  op monitor interval="30s" timeout="30s"

    This configuration creates p_glance-api, a resource for managing the OpenStack Image API service.

  4. Commit your configuration changes by entering the following command from the crm configure menu:

    commit

Pacemaker then starts the OpenStack Image API service and its dependent resources on one of your nodes.

Configure OpenStack Image service API

Edit the /etc/glance/glance-api.conf file to configure the OpenStack Image service:

# We have to use MySQL connection to store data:
sql_connection=mysql://glance:password@10.0.0.11/glance
# Alternatively, you can switch to pymysql,
# a new Python 3 compatible library and use
# sql_connection=mysql+pymysql://glance:password@10.0.0.11/glance
# and be ready when everything moves to Python 3.
# Ref: https://wiki.openstack.org/wiki/PyMySQL_evaluation

# We bind OpenStack Image API to the VIP:
bind_host = 10.0.0.11

# Connect to OpenStack Image registry service:
registry_host = 10.0.0.11

# We send notifications to High Available RabbitMQ:
notifier_strategy = rabbit
rabbit_host = 10.0.0.11

[TODO: need more discussion of these parameters]

Configure OpenStack services to use the highly available OpenStack Image API

Your OpenStack services must now point their OpenStack Image API configuration to the highly available, virtual cluster IP address instead of pointing to the physical IP address of an OpenStack Image API server as you would in a non-HA cluster.

For example, if your OpenStack Image API service IP address is 10.0.0.11 (as in the configuration explained here), you would use the following configuration in your nova.conf file:

[glance]
# ...
api_servers = 10.0.0.11
# ...

You must also create the OpenStack Image API endpoint with this IP address. If you are using both private and public IP addresses, create two virtual IP addresses and define your endpoint. For example:

$ openstack endpoint create --region $KEYSTONE_REGION \
  image public http://PUBLIC_VIP:9292

$ openstack endpoint create --region $KEYSTONE_REGION \
  image admin http://10.0.0.11:9292

$ openstack endpoint create --region $KEYSTONE_REGION \
  image internal http://10.0.0.11:9292