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)
1. Install Linux-HA on both nodes
2. Build a DRBD resource for the Hobbit files, as described in
http://www.drbd.org/docs/about/
3. Setup a Hobbit group
4. Setup a failover IP resource in the Hobbit group, with a DNS entry if you
have DNS
5. Install apache, and setup an apache failover resource in the Hobbit group
for it
6. Setup a colocation constraint, and bind the Hobbit group to the DRBD
resource
7. Setup an order constraint, to have DRBD started before Hobbit starts
8. 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.
9. 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)
10. Try to start Hobbit: It should run as normal.
11. 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:
12. Copy the attached script "hobbit" to /usr/lib/ocf/resource.d/heartbeat/
ON BOTH NODES
13. Setup a Hobbit resource (e.g. by using the hb_gui and selecting "hobbit",
which should be visible after a restart of the GUI).
14. 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
--
Harald Husemann
Netzwerk- und Systemadministrator
Operation Management Center (OMC)
MATERNA GmbH
Information & Communications
Westfalendamm 98
44141 Dortmund
Geschäftsführer: Dr. Winfried Materna, Helmut an de Meulen, Ralph Hartwig
Amtsgericht Dortmund HRB 5839
Tel: +49 231 9505 222
Fax: +49 231 9505 100
www.annyway.com <http://www.annyway.com/>
www.materna.com <http://www.materna.com/>