<div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif"><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Jul 19, 2014 at 12:03 AM, Pranith Kumar Karampuri <span dir="ltr"><<a href="mailto:pkarampu@redhat.com" target="_blank">pkarampu@redhat.com</a>></span> wrote:<br>
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<div>On 07/18/2014 05:43 PM, Andrew Lau
wrote:<br>
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<div class="gmail_quote">On Fri, Jul 18, 2014 at 10:06 PM,
Vijay Bellur <span dir="ltr"><<a href="mailto:vbellur@redhat.com" target="_blank">vbellur@redhat.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">[Adding
gluster-devel]
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On 07/18/2014 05:20 PM, Andrew Lau wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Hi
all,<br>
<br>
As most of you have got hints from previous messages,
hosted engine<br>
won't work on gluster . A quote from BZ1097639<br>
<br>
"Using hosted engine with Gluster backed storage is
currently something<br>
we really warn against.<br>
<br>
<br>
I think this bug should be closed or re-targeted at
documentation, because there is nothing we can do
here. Hosted engine assumes that all writes are atomic
and (immediately) available for all hosts in the
cluster. Gluster violates those assumptions.<br>
"<br>
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I tried going through BZ1097639 but could not find much
detail with respect to gluster there.<br>
<br>
A few questions around the problem:<br>
<br>
1. Can somebody please explain in detail the scenario that
causes the problem?<br>
<br>
2. Is hosted engine performing synchronous writes to
ensure that writes are durable?<br>
<br>
Also, if there is any documentation that details the
hosted engine architecture that would help in enhancing
our understanding of its interactions with gluster.
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<br>
Now my question, does this theory prevent a scenario
of perhaps<br>
something like a gluster replicated volume being
mounted as a glusterfs<br>
filesystem and then re-exported as the native kernel
NFS share for the<br>
hosted-engine to consume? It could then be possible to
chuck ctdb in<br>
there to provide a last resort failover solution. I
have tried myself<br>
and suggested it to two people who are running a
similar setup. Now<br>
using the native kernel NFS server for hosted-engine
and they haven't<br>
reported as many issues. Curious, could anyone
validate my theory on this?<br>
<br>
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If we obtain more details on the use case and obtain
gluster logs from the failed scenarios, we should be able
to understand the problem better. That could be the first
step in validating your theory or evolving further
recommendations :).<br>
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<div style="font-family:tahoma,sans-serif">I'm not sure how
useful this is, but Jiri Moskovcak tracked this down in
an off list message.</div>
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<div style="font-family:tahoma,sans-serif">Message Quote:</div>
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<div style="font-family:tahoma,sans-serif">==</div>
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<div style="font-family:tahoma,sans-serif">
<span style="font-family:arial,sans-serif;font-size:13px">We
were able to track it down to this (thanks Andrew for
providing the testing setup):</span></div>
<br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">-b686-4363-bb7e-dba99e5789b6/</span><span style="font-family:arial,sans-serif;font-size:13px">h</span><span style="font-family:arial,sans-serif;font-size:13px">a_agent
service_type=</span><span style="font-family:arial,sans-serif;font-size:13px">hosted</span><span style="font-family:arial,sans-serif;font-size:13px">-</span><span style="font-family:arial,sans-serif;font-size:13px">engine</span><span style="font-family:arial,sans-serif;font-size:13px">'</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">Traceback
(most recent call last):</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">
File "/usr/lib/python2.6/site-</span><span style="font-family:arial,sans-serif;font-size:13px">packa</span><span style="font-family:arial,sans-serif;font-size:13px">ges/ovirt_hosted_engine_</span><span style="font-family:arial,sans-serif;font-size:13px">ha/</span><span style="font-family:arial,sans-serif;font-size:13px">broker/listener.py",
line 165, in handle</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">
response = "success " + self._dispatch(data)</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">
File "/usr/lib/python2.6/site-</span><span style="font-family:arial,sans-serif;font-size:13px">packa</span><span style="font-family:arial,sans-serif;font-size:13px">ges/ovirt_hosted_engine_</span><span style="font-family:arial,sans-serif;font-size:13px">ha/</span><span style="font-family:arial,sans-serif;font-size:13px">broker/listener.py",
line 261, in _dispatch</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">
.get_all_stats_for_service_</span><span style="font-family:arial,sans-serif;font-size:13px">typ</span><span style="font-family:arial,sans-serif;font-size:13px">e(**options)</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">
File "/usr/lib/python2.6/site-</span><span style="font-family:arial,sans-serif;font-size:13px">packa</span><span style="font-family:arial,sans-serif;font-size:13px">ges/ovirt_hosted_engine_</span><span style="font-family:arial,sans-serif;font-size:13px">ha/</span><span style="font-family:arial,sans-serif;font-size:13px">broker/storage_broker.py",
line 41, in get_all_stats_for_service_type</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">
d = self.get_raw_stats_for_</span><span style="font-family:arial,sans-serif;font-size:13px">service</span><span style="font-family:arial,sans-serif;font-size:13px">_type(storage_dir,
service_type)</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">
File "/usr/lib/python2.6/site-</span><span style="font-family:arial,sans-serif;font-size:13px">packa</span><span style="font-family:arial,sans-serif;font-size:13px">ges/ovirt_hosted_engine_</span><span style="font-family:arial,sans-serif;font-size:13px">ha/</span><span style="font-family:arial,sans-serif;font-size:13px">broker/storage_broker.py",
line 74, in get_raw_stats_for_service_type</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">
f = os.open(path, direct_flag | os.O_RDONLY)</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">OSError:
[Errno 116] Stale file handle: '/rhev/data-center/mnt/</span><span style="font-family:arial,sans-serif;font-size:13px">localho</span><span style="font-family:arial,sans-serif;font-size:13px">st:_mnt_hosted-</span><span style="font-family:arial,sans-serif;font-size:13px">engine</span><span style="font-family:arial,sans-serif;font-size:13px">/</span><span style="font-family:arial,sans-serif;font-size:13px">c898fd2a</span><span style="font-family:arial,sans-serif;font-size:13px">-b686-4363-bb7e-</span><span style="font-family:arial,sans-serif;font-size:13px">dba99e5789b6/</span><span style="font-family:arial,sans-serif;font-size:13px">ha_agent/</span><span style="font-family:arial,sans-serif;font-size:13px">hosted</span><span style="font-family:arial,sans-serif;font-size:13px">-</span><span style="font-family:arial,sans-serif;font-size:13px">engine</span><span style="font-family:arial,sans-serif;font-size:13px">.</span><span style="font-family:arial,sans-serif;font-size:13px">metadata'</span><br style="font-family:arial,sans-serif;font-size:13px">
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Andrew/Jiri,<br>
Would it be possible to post gluster logs of both the mount
and bricks on the bz? I can take a look at it once. If I gather
nothing then probably I will ask for your help in re-creating the
issue.<br>
<br>
Pranith<br></div></blockquote><div><br></div><div><div class="gmail_default" style="font-family:tahoma,sans-serif">Unfortunately, I don't have the logs for that setup any more.. I'll try replicate when I get a chance. If I understand the comment from the BZ, I don't think it's a gluster bug per-say, more just how gluster does its replication.</div>
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<div style="font-family:tahoma,sans-serif"><span style="font-size:13px;font-family:arial,sans-serif">It's
definitely connected to the storage which leads us to
the </span><span style="font-size:13px;font-family:arial,sans-serif">gluster</span><span style="font-size:13px;font-family:arial,sans-serif">,
I'm not very familiar with the </span><span style="font-size:13px;font-family:arial,sans-serif">gluster</span><span style="font-size:13px;font-family:arial,sans-serif"> so
I need to check this with our </span><span style="font-size:13px;font-family:arial,sans-serif">gluster</span><span style="font-size:13px;font-family:arial,sans-serif"> gurus.</span></div>
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<div style="font-family:tahoma,sans-serif">==</div>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Thanks,<br>
Vijay<br>
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