Hi folks,
as written to the list a few days ago, we're running Hobbit on a Linux HA-2 cluster with DRBD. Runs very nice, and the setup is not very complicated, so as promised, here are some notes if you like to make your Hobbit high available: (This is more or less a summary of our installation, and not tested but written from memory - maybe someone can test it and write a real step-by-step guide)
- Install Linux-HA on both nodes
- Build a DRBD resource for the Hobbit files, as described in http://www.drbd.org/docs/about/
- Setup a Hobbit group
- Setup a failover IP resource in the Hobbit group, with a DNS entry if you have DNS
- Install apache, and setup an apache failover resource in the Hobbit group for it
- Setup a colocation constraint, and bind the Hobbit group to the DRBD resource
- Setup an order constraint, to have DRBD started before Hobbit starts
- Setup a Hobbit user as usual, and link its home directory to the DRBD resource. This way, all Hobbit config files, datafiles, etc. are on DRBD , and you don't have to fiddle around with syncing the configs etc.
- Configure Hobbit sources as usual, with some notes:
- Use the failover IP as Hobbit's server IP
- Everywhere you would enter the Hobbitserver's name, enter the name of the failover IP (e.g., for the web-based stuff)
Try to start Hobbit: It should run as normal.
Stop it, switch everything to the other node, and try to start Hobbit again. If everything's okay, stop it, and you're ready for the final step:
Copy the attached script "hobbit" to /usr/lib/ocf/resource.d/heartbeat/ ON BOTH NODES
Setup a Hobbit resource (e.g. by using the hb_gui and selecting "hobbit", which should be visible after a restart of the GUI).
Start the Hobbit resource
That's it, now, your Hobbit should be redundant and monitored by the OCF system.
Some final notes:
- Be sure to use the failover IP as BBDISPLAY on all your clients
- NEVER start/stop/restart Hobbit with hobbit.sh, since you could end up with two running Hobbit instances (the cluster will see that hobbitd is down, and start it itself). reload is (obviously) okay, since it will not restart the process.
- If you like to monitor your Hobbit nodes themselves, install a second Hobbit (client) instance under a different user (e.g. hobbitmon), which is not under cluster control. Without this, only the active node will be monitored, since the server (and the client) runs only on this node.
HTH,
hh
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