High-availability agent communication

Agents communicate with the server over JMS and HTTP or HTTPS. These modes of communication are handled differently in a high availability scenario.

JMS communication

JMS communications is subscription-based. All agents subscribe to all topics and filter the list with their agent ID. For this reason, assigning unique IDs to agents is required.

For JMS-based communications, agents can be configured in two ways:

Approach 1: Agents are individually configured for failover. If an agent fails to connect to a server or agent relay, the agent connects to failover servers or agent relays. See Configuring agents for failover.
Approach 2: Agents connect to a single agent relay that is configured for failover. See Configuring agent relays for failover.

Approach 1 works best because it allows for you to configure stable failover configurations in ActiveMQ.

Note: Do not configure a load balancer to distribute requests for the agent communication JMS port. To ensure agent and agent relay availability, configure them for failover.

HTTP or HTTPS communication

A standard load balancer handles HTTP or HTTPS server-agent communications. Authentication is run on every request; any server can run validation for any request. You configure HTTP or HTTPS server-agent communication when you configure your cluster of servers. See Setting up clusters of servers.

In case of server failure, user-server authentication must be redone unless the ‘remember me’ cookie is used.