[ClusterLabs Developers] OCF_RESKEY_CRM_meta_notify_active_* always empty
Ken Gaillot
kgaillot at redhat.com
Mon Aug 1 15:27:53 UTC 2016
On 07/29/2016 06:19 PM, Andrew Beekhof wrote:
> Urgh. I must be confused with sles11.
> In any case, the first version of pacemaker was identical to the last heartbeat crm.
>
> I don't recall the ocfs2 agent changing design while I was there, so 11 may be broken too
I just realized *_active_* is only broken for master/slave clones.
Filesystem is not master/slave, so it wouldn't have any issue.
> Sent from my iPhone
>
>> On 30 Jul 2016, at 8:51 AM, Ken Gaillot <kgaillot at redhat.com> wrote:
>>
>>> On 07/29/2016 05:41 PM, Andrew Beekhof wrote:
>>>
>>>
>>> Sent from my iPhone
>>>
>>>> On 30 Jul 2016, at 8:32 AM, Ken Gaillot <kgaillot at redhat.com> wrote:
>>>>
>>>> I finally had time to investigate this, and it definitely is broken.
>>>>
>>>> The only existing heartbeat RA to use the *_notify_active_* variables is
>>>> Filesystem, and it only does so for OCFS2 on SLES10, which didn't even
>>>> ship pacemaker,
>>>
>>> I'm pretty sure it did
>>
>> All I could find was:
>>
>> "SLES 10 did not yet ship pacemaker, but heartbeat with the builtin crm"
>>
>> http://oss.clusterlabs.org/pipermail/pacemaker/2014-July/022232.html
>>
>> I'm sure people were compiling it, and ClusterLabs probably even
>> provided a repo, but it looks like sles didn't ship it.
>>
>> The issue is that the code that builds the active list checks for role
>> RSC_ROLE_STARTED rather than RSC_ROLE_SLAVE + RSC_ROLE_MASTER, so I
>> don't think it ever would have worked.
>>
>>>
>>>> so I'm guessing it's been broken from the beginning of
>>>> pacemaker.
>>>>
>>>> The fix looks straightforward, so I should be able to take care of it soon.
>>>>
>>>> Filed bug http://bugs.clusterlabs.org/show_bug.cgi?id=5295
>>>>
>>>>> On 05/08/2016 04:57 AM, Jehan-Guillaume de Rorthais wrote:
>>>>> Le Fri, 6 May 2016 15:41:11 -0500,
>>>>> Ken Gaillot <kgaillot at redhat.com> a écrit :
>>>>>
>>>>>>> On 05/03/2016 05:30 PM, Jehan-Guillaume de Rorthais wrote:
>>>>>>> Le Tue, 3 May 2016 21:10:12 +0200,
>>>>>>> Jehan-Guillaume de Rorthais <jgdr at dalibo.com> a écrit :
>>>>>>>
>>>>>>>> Le Mon, 2 May 2016 17:59:55 -0500,
>>>>>>>> Ken Gaillot <kgaillot at redhat.com> a écrit :
>>>>>>>>
>>>>>>>>>> On 04/28/2016 04:47 AM, Jehan-Guillaume de Rorthais wrote:
>>>>>>>>>> Hello all,
>>>>>>>>>>
>>>>>>>>>> While testing and experiencing with our RA for PostgreSQL, I found the
>>>>>>>>>> meta_notify_active_* variables seems always empty. Here is an example of
>>>>>>>>>> these variables as they are seen from our RA during a
>>>>>>>>>> migration/switchover:
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> {
>>>>>>>>>> 'type' => 'pre',
>>>>>>>>>> 'operation' => 'demote',
>>>>>>>>>> 'active' => [],
>>>>>>>>>> 'inactive' => [],
>>>>>>>>>> 'start' => [],
>>>>>>>>>> 'stop' => [],
>>>>>>>>>> 'demote' => [
>>>>>>>>>> {
>>>>>>>>>> 'rsc' => 'pgsqld:1',
>>>>>>>>>> 'uname' => 'hanode1'
>>>>>>>>>> }
>>>>>>>>>> ],
>>>>>>>>>>
>>>>>>>>>> 'master' => [
>>>>>>>>>> {
>>>>>>>>>> 'rsc' => 'pgsqld:1',
>>>>>>>>>> 'uname' => 'hanode1'
>>>>>>>>>> }
>>>>>>>>>> ],
>>>>>>>>>>
>>>>>>>>>> 'promote' => [
>>>>>>>>>> {
>>>>>>>>>> 'rsc' => 'pgsqld:0',
>>>>>>>>>> 'uname' => 'hanode3'
>>>>>>>>>> }
>>>>>>>>>> ],
>>>>>>>>>> 'slave' => [
>>>>>>>>>> {
>>>>>>>>>> 'rsc' => 'pgsqld:0',
>>>>>>>>>> 'uname' => 'hanode3'
>>>>>>>>>> },
>>>>>>>>>> {
>>>>>>>>>> 'rsc' => 'pgsqld:2',
>>>>>>>>>> 'uname' => 'hanode2'
>>>>>>>>>> }
>>>>>>>>>> ],
>>>>>>>>>>
>>>>>>>>>> }
>>>>>>>>>>
>>>>>>>>>> In case this comes from our side, here is code building this:
>>>>>>>>>>
>>>>>>>>>> https://github.com/dalibo/PAF/blob/6e86284bc647ef1e81f01f047f1862e40ba62906/lib/OCF_Functions.pm#L444
>>>>>>>>>>
>>>>>>>>>> But looking at the variable itself in debug logs, I always find it empty,
>>>>>>>>>> in various situations (switchover, recover, failover).
>>>>>>>>>>
>>>>>>>>>> If I understand the documentation correctly, I would expect 'active' to
>>>>>>>>>> list all the three resources, shouldn't it? Currently, to bypass this, we
>>>>>>>>>> consider: active == master + slave
>>>>>>>>>
>>>>>>>>> You're right, it should. The pacemaker code that generates the "active"
>>>>>>>>> variables is the same used for "demote" etc., so it seems unlikely the
>>>>>>>>> issue is on pacemaker's side. Especially since your code treats active
>>>>>>>>> etc. differently from demote etc., it seems like it must be in there
>>>>>>>>> somewhere, but I don't see where.
>>>>>>>>
>>>>>>>> The code treat active, inactive, start and stop all together, for any
>>>>>>>> cloned resource. If the resource is a multistate, it adds promote, demote,
>>>>>>>> slave and master.
>>>>>>>>
>>>>>>>> Note that from this piece of code, the 7 other notify vars are set
>>>>>>>> correctly: start, stop, inactive, promote, demote, slave, master. Only
>>>>>>>> active is always missing.
>>>>>>>>
>>>>>>>> I'll investigate and try to find where is hiding the bug.
>>>>>>>
>>>>>>> So I added a piece of code to dump the **all** the environment variables to
>>>>>>> a temp file as early as possible **to avoid any interaction with our perl
>>>>>>> module** in the code of the RA, ie.:
>>>>>>>
>>>>>>> BEGIN {
>>>>>>> use Time::HiRes qw(time);
>>>>>>> my $now = time;
>>>>>>> open my $fh, ">", "/tmp/test-$now.env.txt";
>>>>>>> printf($fh "%-20s = ''%s''\n", $_, $ENV{$_}) foreach sort keys %ENV;
>>>>>>> }
>>>>>>>
>>>>>>> Then I started my cluster and set maintenance-mode=false while no resources
>>>>>>> where running. So the debug files contains the probe action, start on all
>>>>>>> nodes, one promote on the master and the first monitors. The "*active"
>>>>>>> variables are always empty anywhere in the cluster. Find in attachment the
>>>>>>> result of the following command on the master node:
>>>>>>>
>>>>>>> for i in test-*; do echo "===== $i ====="; grep OCF_ $i; done >
>>>>>>> debug-env.txt
>>>>>>>
>>>>>>> I'm using Pacemaker 1.1.13-10.el7_2.2-44eb2dd under CentOS 7.2.1511.
>>>>>>>
>>>>>>> For completeness, I added the Pacemaker configuration I use for my 3 node
>>>>>>> dev/test cluster.
>>>>>>>
>>>>>>> Let me know if you think of more investigations and test I could run on this
>>>>>>> issue. I'm out of ideas for tonight (and I really would prefer having this
>>>>>>> bug on my side).
>>>>>>
>>>>>> From your environment dumps, what I think is happening is that you are
>>>>>> getting multiple notifications (start, pre-promote, post-promote) in a
>>>>>> single cluster transition. So the variables reflect the initial state of
>>>>>> that transition -- none of the instances are active, all three are being
>>>>>> started (so the nodes are in the "*_start_*" variables), and one is
>>>>>> being promoted.
>>>>>
>>>>>
>>>>> Yes, this is what happening here. It's embarrassing I didn't thought about
>>>>> that :)
>>>>>
>>>>>> The starts will be done before the promote. If one of the starts fails,
>>>>>> the transition will be aborted, and a new one will be calculated. So, if
>>>>>> you get to the promote, you can assume anything in "*_start_*" is now
>>>>>> active.
>>>>>
>>>>> I did another simple test:
>>>>>
>>>>> * 3 ms clones are running on hanode1 hanode2 hanode3
>>>>> * master role is on hanode1
>>>>> * I move the master role to hanode 2 using:
>>>>> "pcs resource move pgsql-ha hanode2 --master"
>>>>>
>>>>> The transition gives us:
>>>>>
>>>>> * demote on hanode1
>>>>> * promote en hanode2
>>>>>
>>>>> I suppose all the three clone on hanode1, hanode2 and hanode3 should appear in
>>>>> active env variable in this context, isn't it?
>>>>>
>>>>> Please, find in attachment the environment dumps of this transition from
>>>>> hanode1. You'll see both "OCF_RESKEY_CRM_meta_notify_active_resource" and
>>>>> "OCF_RESKEY_CRM_meta_notify_active_uname" only contains one char: a space.
>>>>>
>>>>> I start looking at the Pacemaker code, at least to have a better understanding
>>>>> on where environment variables are set and when they are available. I was out
>>>>> of luck so far but I lack of time. Any pointers would be appreciated :)
>>>>>
>>>>>>> On a side note, I noticed with these debug files that the notify
>>>>>>> variables where also available outside of notify actions (start and notify
>>>>>>> here). Are they always available during "transition actions" (start, stop,
>>>>>>> promote, demote)? Checking at the mysql RA, they are using
>>>>>>> OCF_RESKEY_CRM_meta_notify_master_uname during the start action. So I
>>>>>>> suppose it's safe?
>>>>>>
>>>>>> Good question, I've never tried that before. I'm reluctant to say it's
>>>>>> guaranteed; it's possible seeing them in the start action is a side
>>>>>> effect of the current implementation and could theoretically change in
>>>>>> the future. But if mysql is relying on it, I suppose it's
>>>>>> well-established already, making changing it unlikely ...
>>>>>
>>>>> Thank you very much for this clarification. Presently we keep in a private
>>>>> attribute what we //think// (we can not rely on active_uname :/) are the active
>>>>> uname for the ms resource. As it seems the notify vars appears outside of notify
>>>>> action is just a side effect of the current implementation, I prefer to stay
>>>>> away from them when we are not in a notify action and keep our current
>>>>> implementation.
>>>>>
>>>>> Thank you,
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