10.0 High Availability

The high availability or failover feature works by using a hierarchical view of the hosts associated with the Framework.  

The hierarchy of hosts is created by using the Hosts console to group hosts into domains and subdomains, which are representative of your enterprise network structure. This effectively gives them a chain of command, where they always address requests to managers in their immediate subdomain before moving along a branch to another subdomain or parent domain.

To achieve an effective failover environment, at least two Framework Manager packages must be deployed across the same Framework. The licensing model is not based on how many managers or agents are deployed, but how many hosts the Framework is deployed on. This means that there are no restrictions on how many Framework Manager packages you can deploy.

The Registry Manager controls a database that records the location and status of each package deployed on each of the hosts within the Framework. A copy of this information is held at each host by the Registry Agent package that is included as part of the agent installation. The distributed information is used to calculate the route to the appropriate manager for requests from any agent registered on the Framework. The structure of the registry data enables each host to determine which Framework Manager on the Framework should be the target of requests, and which Framework Manager to use if there is a failure or withdrawal of the initially selected Framework Manager.

The failover feature automatically and transparently redirects requests from a failed or withdrawn Framework Manager to the next available manager of the same type.  The agent automatically connects to a manager that is next in line in accordance with your defined hierarchy.

Table 10-1 Creating a Failover Environment

This diagram shows an example of a typical way to create an effective failover environment.

Deployment: Deploy the Command Control Manager package on the Framework Manager, Agent 1, and Agent 3 hosts.

Who authenticates to whom: By default, each agent contacts the following host for Command Control authorization:

  • Agent 1 and 2 contact Agent 1.
  • Agent 3 and 4 contact Agent 3.

Examples:

  1. Agent 3 is downed for maintenance.  Agent 4 seeks authorization from Agent 1.

  2. Agent 1 is also downed because of a broken network card.  Agents 2, 3, and 4 seek authorization from the Framework Manager.

  3. The Command Control Manager package is removed from the Framework Manager and the Agent 1 is still broken. Agents 2, 3, and 4 seek authorization from Agent 3, considering Agent 3 is up and Agent 1 is still broken.

IMPORTANT:If an additional subdomain is added, agents under Subdomain 1 and 1a then seek authorization from the new Subdomain if no other Command Control Manager is available.

If the primary fails, see Promoting Managers When the Primary Manager Fails.