[Pacemaker] [Question] About "quorum-policy=freeze" and "promote".

[Andrew Beekhof]

On 8 May 2014, at 1:37 pm, renayama19661014 at ybb.ne.jp wrote:

> Hi All,
> 
> I composed Master/Slave resource of three nodes that set quorum-policy="freeze".
> (I use Stateful in Master/Slave resource.)
> 
> ---------------------------------
> Current DC: srv01 (3232238280) - partition with quorum
> Version: 1.1.11-830af67
> 3 Nodes configured
> 9 Resources configured
> 
> 
> Online: [ srv01 srv02 srv03 ]
> 
> Resource Group: grpStonith1
>     prmStonith1-1      (stonith:external/ssh): Started srv02 
> Resource Group: grpStonith2
>     prmStonith2-1      (stonith:external/ssh): Started srv01 
> Resource Group: grpStonith3
>     prmStonith3-1      (stonith:external/ssh): Started srv01 
> Master/Slave Set: msPostgresql [pgsql]
>     Masters: [ srv01 ]
>     Slaves: [ srv02 srv03 ]
> Clone Set: clnPingd [prmPingd]
>     Started: [ srv01 srv02 srv03 ]
> ---------------------------------
> 
> 
> Master resource starts in all nodes when I interrupt the internal communication of all nodes.
> 
> ---------------------------------
> Node srv02 (3232238290): UNCLEAN (offline)
> Node srv03 (3232238300): UNCLEAN (offline)
> Online: [ srv01 ]
> 
> Resource Group: grpStonith1
>     prmStonith1-1      (stonith:external/ssh): Started srv02 
> Resource Group: grpStonith2
>     prmStonith2-1      (stonith:external/ssh): Started srv01 
> Resource Group: grpStonith3
>     prmStonith3-1      (stonith:external/ssh): Started srv01 
> Master/Slave Set: msPostgresql [pgsql]
>     Masters: [ srv01 ]
>     Slaves: [ srv02 srv03 ]
> Clone Set: clnPingd [prmPingd]
>     Started: [ srv01 srv02 srv03 ]
> (snip)
> Node srv01 (3232238280): UNCLEAN (offline)
> Node srv03 (3232238300): UNCLEAN (offline)
> Online: [ srv02 ]
> 
> Resource Group: grpStonith1
>     prmStonith1-1      (stonith:external/ssh): Started srv02 
> Resource Group: grpStonith2
>     prmStonith2-1      (stonith:external/ssh): Started srv01 
> Resource Group: grpStonith3
>     prmStonith3-1      (stonith:external/ssh): Started srv01 
> Master/Slave Set: msPostgresql [pgsql]
>     Masters: [ srv01 srv02 ]
>     Slaves: [ srv03 ]
> Clone Set: clnPingd [prmPingd]
>     Started: [ srv01 srv02 srv03 ]
> (snip)
> Node srv01 (3232238280): UNCLEAN (offline)
> Node srv02 (3232238290): UNCLEAN (offline)
> Online: [ srv03 ]
> 
> Resource Group: grpStonith1
>     prmStonith1-1      (stonith:external/ssh): Started srv02 
> Resource Group: grpStonith2
>     prmStonith2-1      (stonith:external/ssh): Started srv01 
> Resource Group: grpStonith3
>     prmStonith3-1      (stonith:external/ssh): Started srv01 
> Master/Slave Set: msPostgresql [pgsql]
>     Masters: [ srv01 srv03 ]
>     Slaves: [ srv02 ]
> Clone Set: clnPingd [prmPingd]
>     Started: [ srv01 srv02 srv03 ]
> ---------------------------------
> 
> I think even if the cluster loses Quorum, being "promote" the Master / Slave resource that's specification of Pacemaker.
> 
> Is it responsibility of the resource agent side to prevent a state of these plural Master?

No.

In this scenario, no nodes have quorum and therefor no additional instances should have been promoted.  Thats the definition of "freeze" :)
Even if one partition DID have quorum, no instances should have been promoted without fencing occurring first.

> * I think that drbd-RA has those functions.
> * But, there is no function in Stateful-RA.
> * As an example, I think that the mechanism such as drbd is necessary by all means when I make a resource of Master/Slave newly.
> 
> Will my understanding be wrong?
> 
> Best Regards,
> Hideo Yamauchi.
> 
> 
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