openstack-manuals/doc/ha-guide/source/storage-ha-image.rst

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:

• glance-api-pacemaker
• glance-api-configure
• glance-services

This section assumes that you are familiar with the documentation for installing the OpenStack Image API service.

Add OpenStack Image API resource to Pacemaker

You must first download the resource agent to your system:

# cd /usr/lib/ocf/resource.d/openstack
# wget https://git.openstack.org/cgit/openstack/openstack-resource-agents/plain/ocf/glance-api
# chmod a+rx *

You can now add the Pacemaker configuration for the OpenStack Image API resource. Use the crm configure command to connect to the Pacemaker cluster and 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.

The crm configure command supports batch input, so you may copy and paste the above 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.

After completing these steps, commit your configuration changes by entering commit from the crm configure menu. 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 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 OpenStack Compute, 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, you should create two virtual IP addresses and define your endpoint like this:

$ openstack endpoint create image --region $KEYSTONE_REGION \
--publicurl 'http://PUBLIC_VIP:9292' \
--adminurl 'http://10.0.0.11:9292' \
--internalurl 'http://10.0.0.11:9292'