Xen users - Jul 2006 - Notes: DRBD, HA for NFS on Xen guest domains in FC5 using LVM devices.

This a papertrail of my effort in this subject. Figured, I''ll preserve
the
findings/results in this email trail should anyone else also traverse along
the same path. After a few trials, hiccups, I was able to install a HA NFS
system between two guest doms. Effectively, it involved the following:

1) Use FC5 as host/domU

2) Download, install, build Xen kernels from xen-unstable - base=2.6.16.13

3) I tried to build DRBD (v 0.7.19) module for guest domains (again, using
FC5 and the same kernel). Although I saw some posts that ARCH=xen would make
it work, after a few trials, I gave up and install the sources and built it
within the guest domain and installed it there as well (however, as a part
of installation, I expected the drbd0 thru drbd8 or at least two devices to
be created which I did not so I had to create them manually using mknod
using 147 as the id). For the data and metadata disks/devs, I created a
vol-group within which I created 4 logical volumes - 2 of 3GI s and two of
150M ea. The two small ones were for the metadata for each guest domain, and
the two larger ones were used for the nfs exports (data).

4) Installed heartbeat - v2.0 - again I tried to build this in the host and
upload it on the guest domains - it did not quite work (looks like the
ARCH=xen is a flag that was used, now it does not exist). Built, installed
and configured the two guest domains - fedora1 and fedora2 as the two
servers who also are wired up using drbd.

5) Downloaded nfs utils (not the one from RH), installed it in both the
guest domains. Configured the exports to export the volume which would
reside on the drbd block devices (which would internally use the log vols
that were created in the host/domo).

6) In order to wire up the two guest domains in a cluster - I created vifs
in Xen using two bridges and created routes between the two guests to enable
the control/cluster management path.

7) Got the HA working w/ a cluster resource/IP address

8) Before doing the above, made sure drbd was up and running and relied on
Heartbeat to start the nfs.

9) Simple writes, creates, worked fine - whichever guest domain (fedora1 or
fedora2) had the cluster interface also had the nfs export visible each time
there was a failover/failback. Did the failover-simulation using xm
(un)pause <fedora1/fedora2> for either of the two guest domains.

10) Next to try migration...

--


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users