[Pacemaker] Re: Understanding rules: location, colocation, order. Using with Master/Slave

Serge Dubrouski sergeyfd at gmail.com
Mon Oct 27 14:58:34 EDT 2008 

On Mon, Oct 27, 2008 at 12:43 PM, Adrian Chapela
<achapela.rexistros at gmail.com> wrote:
> Serge Dubrouski escribió:
>>
>> Something like this:
>>
>>      <rsc_order id="drbd0_before_myGroup" first="ms-drbd0"
>> then="myGroup" then-action="start" first-action="promote"/>
>>      <rsc_colocation id="myGroup_on_drbd0" rsc="myGroup"
>> with-rsc="ms-drbd0" with-rsc-role="Master" score="INFINITY"/>
>>      <rsc_location id="primNode" rsc="myGroup">
>>        <rule id="prefered_primNode" score="1000">
>>          <expression attribute="#uname" id="expression.id2242728"
>> operation="eq" value="fc-node1"/>
>>        </rule>
>>      </rsc_location>
>>
>> See that cib.xml that I sent you a couple of days ago. First rule will
>> promote DRBD before starting a group, second will collocate master and
>> a group, third one will place group and master to the desired node.
>>
>
> Yes, I bases my rules on yours, but I can't update my config with your rules
> directly.
> <rsc_order id="drbd0_before_myGroup" first="ms-drbd0" then="mail_Group"
> then-action="start" first-action="promote"/>
>
> This could be like:
> <rsc_order id="drbd0_before_myGroup" from="mail_Group" action="start"
> to="ms-drbd0" to_action="promote"/>
>
> What is the version of your heartbeat ? My 2.99.1 heartbeat didn't

It's processed by pacemaker, not heartbeat. That rule worked all right
under 0.6, 0.7, 1.0:

Refresh in 3s...

============
Last updated: Mon Oct 27 14:52:47 2008
Current DC: fc-node2 (ad6f19b7-228a-48b7-bae0-f95a838bde2a)
2 Nodes configured.
3 Resources configured.
============

Node: fc-node1 (b88f98c6-50f2-463a-a6eb-51abbec645a9): online
Node: fc-node2 (ad6f19b7-228a-48b7-bae0-f95a838bde2a): online

Full list of resources:

Clone Set: DoFencing
    child_DoFencing:0   (stonith:external/xen0):        Started fc-node1
    child_DoFencing:1   (stonith:external/xen0):        Started fc-node2
Master/Slave Set: ms-drbd0
    drbd0:0     (ocf::heartbeat:drbd):  Master fc-node1
    drbd0:1     (ocf::heartbeat:drbd):  Started fc-node2
Resource Group: myGroup
    myIP        (ocf::heartbeat:IPaddr):        Started fc-node1
    fs0 (ocf::heartbeat:Filesystem):    Started fc-node1
    myPgsql     (ocf::heartbeat:pgsql): Started fc-node1

[root at fc-node1 crm]# rpm -qa | grep pacemaker
libpacemaker3-1.0.0-2.1
pacemaker-1.0.0-2.1
[root at fc-node1 crm]#


What error do you get?


> understand the rule.
>>
>> On Mon, Oct 27, 2008 at 12:24 PM, Adrian Chapela
>> <achapela.rexistros at gmail.com> wrote:
>>
>>>
>>> Serge Dubrouski escribió:
>>>
>>>>
>>>> On Mon, Oct 27, 2008 at 12:07 PM, Adrian Chapela
>>>> <achapela.rexistros at gmail.com> wrote:
>>>>
>>>>
>>>>>>
>>>>>> Hello!
>>>>>>
>>>>>> I am working on a cluster with a two Master/Slave instances.
>>>>>>
>>>>>> I have: 2 drbd Master/Slave instance, 1 pingd clone instance, 1 group
>>>>>> with
>>>>>> Filesystem resource.
>>>>>>
>>>>>> ms-drbd0 is the first Master/Slave
>>>>>> ms-drbd1 is the second Master/Slave
>>>>>> mail_Group is the first group, it depends on ms-drbd0
>>>>>> samba_Group is the second group, it depends on ms-drbd1
>>>>>>
>>>>>> I have the next rules:
>>>>>>
>>>>>> <rsc_order id="mail-drbd0_before_fs0" from="Montaxe_mail"
>>>>>> action="start"
>>>>>> to="ms-drbd0" to_action="promote"/>
>>>>>> <rsc_order id="samba-drbd1_before_fs0" from="Montaxe_samba"
>>>>>> action="start"
>>>>>> to="ms-drbd1" to_action="promote"/>
>>>>>> (starts Montaxe_mail when ms-drbd0 has been promoted, start
>>>>>> Montaxe_samba
>>>>>> when ms-drbd1 has been promoted. These rules are ok, I think)
>>>>>>
>>>>>> <rsc_colocation id="mail_Group_on_ms-drbd0" to="ms-drbd0"
>>>>>> to_role="master"
>>>>>> from="mail_Group" score="INFINITY"/>
>>>>>> <rsc_colocation id="samba_Group_on_ms-drbd1" to="ms-drbd1"
>>>>>> to_role="master" from="samba_Group" score="INFINITY"/>
>>>>>> (Run mail_Group only on the master node, run samba_Group on the master
>>>>>> node)
>>>>>>
>>>>>> <rsc_location id="mail:drbd" rsc="ms-drbd0">
>>>>>> <rule id="rule:ms-drbd0" role="master" score="100">
>>>>>>  <expression  attribute="#uname" operation="eq"
>>>>>> value="debianquagga2"/>
>>>>>> </rule>
>>>>>> <rule id="mail_Group:pingd:rule" score="-INFINITY" boolean_op="or">
>>>>>>   <expression id="mail_Group:pingd:expr:undefined" attribute="pingd"
>>>>>> operation="not_defined"/>
>>>>>>   <expression id="mail_Group:pingd:expr:zero" attribute="pingd"
>>>>>> operation="lte" value="0"/>
>>>>>> </rule>
>>>>>> </rsc_location>
>>>>>> <rsc_location id="samba:drbd" rsc="ms-drbd1">
>>>>>> <rule id="rule:ms-drbd1" role="master" score="100">
>>>>>>  <expression  attribute="#uname" operation="eq"
>>>>>> value="debianquagga2"/>
>>>>>> </rule>
>>>>>> <rule id="samba_Group:pingd:rule" score="-INFINITY" boolean_op="or">
>>>>>>   <expression id="samba_Group:pingd:expr:undefined" attribute="pingd"
>>>>>> operation="not_defined"/>
>>>>>>   <expression id="samba_Group:pingd:expr:zero" attribute="pingd"
>>>>>> operation="lte" value="0"/>
>>>>>> </rule>
>>>>>> </rsc_location>
>>>>>> (Select debianquagga2 as Master and if the node lost its connection
>>>>>> take
>>>>>> the score -INFINITY to do failover, it applies to ms-drbd0 and
>>>>>> ms-drbd1)
>>>>>>
>>>>>> With this rules all is working very well but the node selected as
>>>>>> master
>>>>>> isn't "debianquagga2",   Why could be the reason ?
>>>>>>
>>>>>> I using Heartbeat 2.1.4
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> I have attached the cib xml file. If I delete two groups, Master is
>>>>> debianQuagga2, If not, Master is debianQuagga1.
>>>>>
>>>>>
>>>>
>>>> That probably has something to do with how scores are counted for
>>>> groups. In your rsc_location rule for masters you have a really low
>>>> score for assigning master role to debianquagga2. It's possible that
>>>> groups outscore them with default values. I'm not sure in that, that's
>>>> just mu guess. You probably can check this with show score scripts.
>>>>
>>>>
>>>
>>> I will check that, thank you!
>>>
>>>>
>>>> I'd try to assign rsc_location rules to groups, not to master role.
>>>> Your collocation rule will control that groups are on the same nodes
>>>> with the masters. Or you can try to increase your scores from 100 to
>>>> something higher.
>>>>
>>>>
>>>
>>> Ok, but I need that node be a master before than start group because it
>>> depends on the master / slave resource, is that possible changing
>>> collocation ? Could you open my eyes with a simple example ?
>>>
>>>
>>>>>
>>>>> _______________________________________________
>>>>> Pacemaker mailing list
>>>>> Pacemaker at clusterlabs.org
>>>>> http://list.clusterlabs.org/mailman/listinfo/pacemaker
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>
>>> _______________________________________________
>>> Pacemaker mailing list
>>> Pacemaker at clusterlabs.org
>>> http://list.clusterlabs.org/mailman/listinfo/pacemaker
>>>
>>>
>>
>>
>>
>>
>
>
> _______________________________________________
> Pacemaker mailing list
> Pacemaker at clusterlabs.org
> http://list.clusterlabs.org/mailman/listinfo/pacemaker
>



-- 
Serge Dubrouski.

More information about the Pacemaker mailing list