If the machine hosting the domain administration server (DAS) fails, you can recreate the DAS if you have previously backed up the DAS. To recreate a working copy of the DAS, you must have:
One machine (machine1) that contains the original DAS.
A second machine (machine2) that contains a cluster with server instances running applications and catering to clients. The cluster is configured using the DAS on the first machine.
A third backup machine (machine3) where the DAS needs to be recreated in case the first machine crashes.
You must maintain a backup of the DAS from the first machine. Use asadmin backup-domain to backup the current domain.
The following steps are required to migrate the Domain Administration Server from the first machine (machine1) to the third machine (machine3).
Install the Enterprise Server on the third machine just as it is installed on the first machine.
This is required so that the DAS can be properly restored on the third machine and there are no path conflicts.
Install the Enterprise Server administration package using the command-line (interactive) mode.
To activate the interactive command-line mode, invoke the installation program using the console option:
You must have root permission to install using the command-line interface.
Deselect the option to install default domain.
Restoration of backed up domains is only supported on two machines with same architecture and exactly the same installation paths (use same as-install and domain-root-dir on both machines).
Copy the backup ZIP file from the first machine into the domain-root-dir on the third machine.
You can also FTP the file.
Restore the ZIP file onto the third machine.
asadmin restore-domain --filename domain-root-dir/sjsas_backup_v00001.zip --clienthostname machine3 domain1
By specifying the --clienthostname option, you avoid the need to modify the jmx-connector element's client-hostname property in the domain.xml file.
You can backup any domain. However, while recreating the domain, the domain name should be same as the original.
Change domain-root-dir/domain1/generated/tmp directory permissions on the third machine to match the permissions of the same directory on first machine.
The default permissions of this directory are: drwx------ (or 700).
chmod 700 domain-root-dir/domain1/generated/tmp
The example above assumes you are backing up domain1. If you are backing up a domain by another name, you should replace domain1 above with the name of the domain being backed up.
In the domain-root-dir/domain1/config/domain.xml file on the third machine, update the value of the jms-service element's host attribute.
The original setting of this attribute is as follows:
Modify the setting of this attribute as follows:
Start the restored domain on machine3:
asadmin start-domain --user admin-user --password admin-password domain1
The DAS contacts all running node agents and provides the node agents with information for contacting the DAS. The node agents use this information to communicate with the DAS.
For any node agents that are not running when the DAS is restarted, change agent.das.host property value in as-install/nodeagents/nodeagent/agent/config/das.properties on machine2.
This step is not required for node agents that are running when the DAS is restarted.
Restart the node agent on machine2.
Start the cluster instances using the asadmin start-instance command to allow them to synchronize with the restored domain.