To increase the availability of Orchestrator services, you can create a cluster of Orchestrator server instances.

About this task

An Orchestrator cluster consists of at least two Orchestrator server instances that share one database.

Prerequisites

  • Install at least two Orchestrator server instances.

  • Configure the external database that you plan to use as a shared database, so that it can accept connections from the different Orchestrator instances.

    To prevent transactional deadlocks when using Microsoft SQL Server database, you must enable the ALLOW_SNAPSHOT_ISOLATION and READ_COMMITTED_SNAPSHOT database options.

  • If your Microsoft SQL Server database uses dynamic ports, ensure that the SQL Server Browser is running.

  • Synchronize the clocks of the virtual machines that the Orchestrator server instances are installed on.

Procedure

  1. Configure the first Orchestrator node.
    1. Log in to Control Center of the first Orchestrator server as root.
    2. Stop the Orchestrator server service from the Startup Options page.
    3. Configure the connection to the external shared database. For more information, see Configure the Database Connection.

      Changes in configuration, such as certificates, licensing, and authentication provider, must be made after the Orchestrator instances are configured to work with the shared database.

    4. On the Troubleshooting page, click Force plug-ins reinstall.
    5. Configure the authentication provider. See Selecting the Authentication Type.
    6. (Optional) : Set any additional system properties. See Setting System Properties for reference.
    7. (Optional) : Open the Logging Integration page and configure Orchestrator to use a remote log server.
    8. (Optional) : On the Orchestrator Node Settings tab of the Orchestrator Cluster Management page, provide values for the Orchestrator node settings and click Save.

      Option

      Description

      Number of active nodes

      The maximum number of active Orchestrator server instances in the cluster.

      Active nodes are the Orchestrator server instances that run workflows and respond to client requests. If an active Orchestrator node stops responding, an inactive Orchestrator server instance replaces it.

      The default number of active Orchestrator nodes in a cluster is one.

      Heartbeat interval (in milliseconds)

      The time interval, in milliseconds, between two network heartbeats that an Orchestrator node sends to show that it is running.

      The default value is 12 seconds.

      Number of failover heartbeats

      The number of absent heartbeats before an Orchestrator node is considered failed.

      The default value is ten heartbeats.

      The default failover timeout is 2 minutes and is equal to the value of the default heartbeat interval multiplied by the number of the default failover heartbeats.

    9. Verify that the node is configured properly at the Validate Configuration page in Control Center.
    10. (Optional) : Install the external plug-ins.
    11. Start the Orchestrator server service on the first Orchestrator node.
    12. On the Startup Options page, make sure that the Active Configuration Fingerprint string and the Pending Configuration Fingerprint string match.
      Note:

      You might need to refresh the Startup Options page several times until the two strings match.

    13. (Optional) : Configure the external plug-ins.
  2. Configure the Orchestrator cluster.
    1. Log in to Control Center of the second Orchestrator server as root.
    2. Click the Join Node To Cluster tab in the Orchestrator Cluster Management page.
    3. In the Host name text box, enter the host name or IP address of the first Orchestrator server instance.
    4. In the User name and Password text boxes, enter your Control Center credentials.
    5. Click Join.

      The Orchestrator instance clones the configuration of the node, to which it joins.

Results

You have successfully configured a cluster of Orchestrator instances.

What to do next

You can add more Orchestrator server active nodes to the cluster by changing the value of the Number of active nodes text box in the Orchestrator Cluster Management page.