Whenever you switch from a standalone to a clustered PBX there will be an outage. This can last from seconds to an hours depending on how to perform the cutover.
It is possible to install HAAst into a live environment, but the “best” way depends a bit on your situation. If you cannot tolerate downtime, then you need to:
- Install HAAst on the live system but do not start the HAAst service
- Setup the second node (Asterisk and HAAst) but do not start the HAAst service
- Fully configure HAAst so the nodes will see each other
- At the next failure, maintenance window, or opportunity you chose, start the HAAst service on both nodes and the cluster will form
If you are running FreePBX as your configuration generator we do not generally recommend the above approach, as FreePBX will crash/misbehave if you synchronize configuration data from (even slightly) different versions / enabled options / installed options. (And it’s very easy to accidentally install/enable different modules on FreePBX nodes). For this reason if you run FreePBX we recommend the following procedure:
- Install HAAst on the live system (per the installation guide)
- Configure HAAst on the live system
- Apply any Asterisk updates you wish
- Finalize your Asterisk dialplan and ensure Asterisk works as you wish
- During your maintenance window shutdown the PBX
- Use ‘dd’ or similar tool to mirror the PBX to a second PBX
- Restart both PBX’s (leave the new PBX unplugged from the network)
- Customize the second PBX with unique network and HAAst information
- Reconnect the second PBX to the network and the nodes should find each other
- The nodes should now report the cluster is live
At a high level this should get you up and running with a working cluster. Our detailed installation guide has more specifics that take you through each of the steps above. As well, be sure to read the maintenance guide for instructions on updating.
When Telium performs a live site installation, we bring up the cluster with minimal interruption in phone service (unless of course the customer approves more extensive failover test) as described above.
