[Xen-devel] [PATCH] Support "bootloader" mode for "drbd:" devices

[Michael Renner <michael.renner@xxxxxxxxxxx>]

There's a bit of glue missing in xend to support the "bootloader" stanza 
in Guests which use a "drbd:" device as their bootdevice.
This patch extends and supersedes Bug #1438.


To be able to use "bootloader" on drbd devices the following changes 
need to be done:

*) Translation of devicename

_parse_uname which is used by blkdev_uname_to_file which is again used 
by _configureBootloader in XendDomainInfo needs to be able to resolve 
drbd resouces to the corresponding blockdevice to feed to the configured 
bootloader.

*) Activation of drbd device

If the drbd device isn't in Primary mode when the bootloader tries to 
fetch the kernel and initrd, the start of the DomU will fail. To prevent 
this the given drbd device will be made Primary before the bootloader 
gets executed.

The patches need some revising since I'm neither very fluent in Python 
nor familiar with the error handling infrastructure in xend.

subprocess has been replaced by os.popen2 and os.system per comment from 
Masaki Kanno in #1506.

A note on the naming of drbd resouces:

drbd uses mostly resource names in it's userland tools. Because of that 
drbd VBDs, if configured with the "drbd:" type, should always use the 
drbd resource name as suggested by the drbd documentation at 
http://www.drbd.org/users-guide-emb/s-xen-configure-domu.html . My 
patches assume that the VBDs are named accordingly.

Signed-off-by: Michael Renner <michael.renner <at> geizhals.at>


best regards,
Michael Renner


--

Geizhals(R) - Preisvergleich
Preisvergleich Internet Services AG
Obere Donaustrasse 63/2
A-1020 Wien
Tel: +43 1 5811609/87
Fax: +43 1 5811609/55

Handelsgericht Wien | FN 197241K | Firmensitz Wien

--- a/tools/python/xen/xend/XendDomainInfo.py   2009-08-06 15:57:25.000000000 
+0200
+++ b/tools/python/xen/xend/XendDomainInfo.py   2009-09-03 11:57:03.000000000 
+0200
@@ -2894,6 +2893,15 @@
             disk = devinfo[1]['uname']
 
             fn = blkdev_uname_to_file(disk)
+
+            # If this is a drbd volume, check if we need to activate it
+            (disktype, diskname) = disk.split(':', 1)
+            if disktype == 'drbd':
+                (drbdadmstdin, drbdadmstdout) = os.popen2(["/sbin/drbdadm", 
"state", diskname])
+                (state, junk) = drbdadmstdout.readline().split('/', 1)
+                if state == 'Secondary':
+                    os.system('/sbin/drbdadm primary ' + diskname)
+
             taptype = blkdev_uname_to_taptype(disk)
             mounted = devtype == 'tap' and taptype != 'aio' and taptype != 
'sync' and not os.stat(fn).st_rdev
             if mounted:

--- a/tools/python/xen/util/blkif.py    2009-08-06 15:57:25.000000000 +0200
+++ b/tools/python/xen/util/blkif.py    2009-09-03 12:46:33.000000000 +0200
@@ -75,8 +75,17 @@
     fn = taptype = None
     if uname.find(":") != -1:
         (typ, fn) = uname.split(":", 1)
-        if typ in ("phy", "drbd") and not fn.startswith("/"):
+
+        if typ == "phy" and not fn.startswith("/"):
             fn = "/dev/%s" %(fn,)
+
+        if typ == "drbd":
+            if not fn.startswith("drbd"):
+                (drbdadmstdin, drbdadmstdout) = os.popen2(["/sbin/drbdadm", 
"sh-dev", fn])
+                fn = drbdadmstdout.readline().strip()
+            else:
+                fn = "/dev/%s" %(fn,)
+               
         if typ == "tap":
             (taptype, fn) = fn.split(":", 1)
     return (fn, taptype)

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