Configuring Queue Mirroring

In a RabbitMQ cluster, queues can be mirrored across multiple nodes. In the event of a node failure, services are still available because the mirrors will take over services.

This section describes how to configure queue mirroring policies for a virtual host on the RabbitMQ management UI. Queues meet the policies are mirrored queues.

Prerequisite

A cluster RabbitMQ instance has been created.

Configuring RabbitMQ Queue Mirroring

Log in to the management UI of a RabbitMQ instance.
Click the Admin tab.

Figure 1 Admin tab page
(Optional) Perform this step only if you need to specify a virtual host. Otherwise, go to 4.

In the navigation tree on the right, choose Virtual Hosts, specify Name, and click Add virtual host to create a virtual host.
Figure 2 Creating a virtual host

In the navigation tree on the right, choose Policies and set policies for the virtual host.

Figure 3 Setting virtual host policies
Click to enlarge

**Table 1** Policy elements
Parameter	Description
Virtual Host	Specify the virtual host. To set policies for a specific virtual host, select the virtual host created in 3 from the Virtual host drop-down list box. If no virtual host has been created, the default value / is used.
Name	The policy name, which can be customized.
Pattern	Regular expression that defines the pattern for matching queues.
Apply to	Object to which the policy applies.
Priority	A larger value indicates a higher priority.
Definition	Definition of the mirror, which consists of ha-sync-mode, ha-mode, and ha-params. ha-sync-mode: queue synchronization mode. Options: automatic and manual. automatic: Data is automatically synchronized from the master. manual: Data is manually synchronized from the master. ha-mode: queue mirroring mode. Options: all, exactly, and nodes. all: Mirror the queue across all nodes in the cluster. exactly: Mirror the queue to a specific number (determined through ha-params) of nodes in the cluster. nodes: Mirror the queue to specific nodes (determined through ha-params). ha-params: This parameter is used in the ha-mode mode.