Installing for a High Availability Implementation

If you are installing multiple servers for a high availability, or active-active, Deployment Automation server implementation, you should use this procedure. If you are not configuring this type of implementation, you can skip this section. However, if you are in the planning phase of your implementation, it is recommended for you to consult the Server Configuration section to determine the type of server configuration you may need.

To install a server for an active-active configuration:

Install the database. See Database Installation.
Install the first Deployment Automation server. This installs into the designated installation folder, .serena by default, which will be shared with subsequent server installations. Ensure that the installation folder can be accessed by all the machines on the active-active cluster. See Server Installation.
Important: On Windows, the drive should typically be a mapped drive. For example, you could use a common F: drive on all servers, including the main host. UNC paths are not supported if you want to run Deployment Automation as a service.

Note: If you use a cluster with a load balancer, you should modify the External Agent URL and External User URL fields to use the IP address or the DNS name of the cluster. Modify this in the Deployment Automation web application in Administration > System > System Settings.
Install additional servers, making sure to:
- Set the "Install Deployment Automation to:" field to the shared installation folder. To share the installation location, use the following guidelines:
  - The shared network storage should not reside on any of the Deployment Automation servers; otherwise it introduces a dependency on one node always being available and invalidates High Availability principles.
  - Shared storage should be accessed using a symbolic directory link or mapped drive created on each of the Deployment Automation servers.
    
    CAUTION:
    If you use a UNC path on Windows, you cannot run Deployment Automation as a service. Instead, use a mapped drive.
  - The Tomcat service on each of the Deployment Automation servers needs to be configured to run using a domain service account and that account must be given full access to the shared network location, as well as to the Deployment Automation and Tomcat installation directories on each Deployment Automation server.
- Select the Use existing settings option.
Install agents and then see High-availability and Disaster Recovery.