On 11/03/2014 09:26 AM, Dejan Muhamedagic wrote:
On Mon, Nov 03, 2014 at 08:46:00AM +0300, Andrei Borzenkov wrote:
В Mon, 3 Nov 2014 13:32:45 +1100
Andrew Beekhof <and...@beekhof.net> пишет:
On 1 Nov 2014, at 11:03 pm, Patrick Kane <p...@wawd.com> wrote:
Hi all:
In July, list member Ken Gaillot reported occasional nonsensical resource agent
errors using Pacemaker
(http://oss.clusterlabs.org/pipermail/pacemaker/2014-July/022231.html).
We're seeing similar issues with our install. We have a 2 node
corosync/pacemaker failover configuration that is using the
ocf:heartbeat:IPaddr2 resource agent extensively. About once a week, we'll get
an error like this, out of the blue:
Nov 1 05:23:57 lb02 IPaddr2(anon_ip)[32312]: ERROR: Setup problem: couldn't
find command: ip
It goes without saying that the ip command hasn't gone anywhere and all the
paths are configured correctly.
We're currently running 1.1.10-14.el6_5.3-368c726 under CentOS 6 x86_64 inside
of a xen container.
Any thoughts from folks on what might be happening or how we can get additional
debug information to help figure out what's triggering this?
its pretty much in the hands of the agent.
Actually the message seems to be output by check_binary() function
which is part of framework.
Someone complained in the IRC about this issue (another resource
agent though, I think Xen) and they said that which(1) was not
able to find the program. I'd suggest to do strace (or ltrace)
of which(1) at that point (it's in ocf-shellfuncs).
The which(1) utility is a simple tool: it splits the PATH
environment variable and stats the program name appended to each
of the paths. PATH somehow corrupted or filesystem misbehaving?
My guess is that it's the former.
BTW, was there an upgrade of some kind before this started
happening?
I was hoping to have something useful before posting another update, but
since it's come up again, here's what we've found so far:
* The most common manifestation is the "couldn't find command" error. In
various instances it "couldn't find" xm, ip or awk. However, we've seen
two other variations:
lrmd: [3363]: info: RA output: (pan:monitor:stderr) en-destroy: bad
variable name
and
lrmd: [2145]: info: RA output: (ldap-ip:monitor:stderr)
/usr/lib/ocf/resource.d//heartbeat/IPaddr2: 1:
/usr/lib/ocf/resource.d//heartbeat/IPaddr2: : Permission denied
The RA in the first case does not use the string "en-destroy" at all; it
does call a command "xen-destroy". That, to me, is a strong suggestion
of memory corruption somewhere, whether in the RA, the shell, lrmd or a
library used by one of those.
* I have not found any bugs in the RA or its included files.
* I tried setting "debug: on" in corosync.conf, but that did not give
any additional useful information. The resource agent error is still the
first unusual message in the sequence. Here is an example, giving one
successful monitor run and then an occurrence of the issue (the nodes
are a pair of Xen dom0s including pisces, running two Xen domU resources
pan and nemesis):
Sep 13 20:16:56 pisces lrmd: [3509]: debug: rsc:pan monitor[21] (pid 372)
Sep 13 20:16:56 pisces lrmd: [372]: debug: perform_ra_op: resetting
scheduler class to SCHED_OTHER
Sep 13 20:16:56 pisces lrmd: [3509]: debug: rsc:nemesis monitor[32] (pid
409)
Sep 13 20:16:56 pisces lrmd: [409]: debug: perform_ra_op: resetting
scheduler class to SCHED_OTHER
Sep 13 20:16:56 pisces lrmd: [3509]: info: operation monitor[21] on pan
for client 3512: pid 372 exited with return code 0
Sep 13 20:16:57 pisces lrmd: [3509]: info: operation monitor[32] on
nemesis for client 3512: pid 409 exited with return code 0
Sep 13 20:17:06 pisces lrmd: [3509]: debug: rsc:pan monitor[21] (pid 455)
Sep 13 20:17:06 pisces lrmd: [455]: debug: perform_ra_op: resetting
scheduler class to SCHED_OTHER
Sep 13 20:17:07 pisces lrmd: [3509]: info: RA output:
(pan:monitor:stderr) /usr/lib/ocf/resource.d//heartbeat/Xen: 71: local:
Sep 13 20:17:07 pisces lrmd: [3509]: info: RA output:
(pan:monitor:stderr) en-destroy: bad variable name
Sep 13 20:17:07 pisces lrmd: [3509]: info: RA output: (pan:monitor:stderr)
Sep 13 20:17:07 pisces lrmd: [3509]: info: operation monitor[21] on pan
for client 3512: pid 455 exited with return code 2
* I tried reverting several security updates applied in the month or so
before we first saw the issue. Reverting the Debian kernel packages to
3.2.57-3 and then 3.2.54-2 did not help, nor did reverting libxml2 to
libxml2 2.8.0+dfsg1-7+nmu2. None of the other updates from that time
look like they could have any effect.
* Regarding libxml2, I did find that Debian had backported an upstream
patch into its 2.8.0+dfsg1-7+nmu3 that introduced a memory corruption
bug, which upstream later corrected (the bug never made it into an
upstream release, but Debian had backported a specific changeset). I
submitted that as Debian Bug #765770 which was just fixed last week. I
haven't had a chance to apply that to the affected servers yet, but as
mentioned above, reverting to the libxml2 before the introduced bug did
not fix the issue.
* I have not found a way to intentionally reproduce the issue. :-( We
have had 10 occurrences across 3 two-node clusters in five months. Some
of the nodes have had only one occurrence during that time, but one pair
gets the most of them. With the time between occurrences, it's hard to
do something like strace on lrmd, though that's probably a good way
forward, scripting something to deal with the output reasonably.
* There does not seem to be any correlation with how long the node has
been up. Checking RAM usage of corosync and lrmd on all nodes over about
two weeks shows little to no change, so I don't suspect a leak. Most of
our errors have occurred in the Xen RA, but probably only because that's
the RA we use most; we've also seen it in IPaddr2.
* My next idea would be to compile/install the latest versions of at
least pacemaker and the resource agents. However I am in the middle of
changing jobs, and unfortunately do not have much time left for this. My
new job will have plenty of time to spend on pacemaker ;-) so I may be
able to give updates later. Debian's "jessie" release freezes this week,
so I'm hoping that I will have time to at least get a test cluster up
running the somewhat newer versions in that (pacemaker 1.1.10, corosync
1.4.6).
-- Ken Gaillot <kjgai...@gleim.com>
Network Operations Center, Gleim Publications
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