[Pacemaker] How does ptest work?

Andrew Beekhof beekhof at gmail.com
Wed Jan 2 15:38:50 EST 2008

On Jan 2, 2008, at 9:13 PM, Michael Schwartzkopff wrote:

> Hi,
> I just started to play around with ptest. Really nice, esp. the  
> graphs.
> But one thing I do not understand ...
> 1) I copy the active CIB to a file: cibadmin -Q > tmp.xml
> 2) I do changes in that file: vi  tmp.xml
> In particular I change the IP address of a IPaddr2 resource.
> 3) I run ptest and it tells me (correctly) that it would shut down the
> resource and start ist again.
> How does ptest know what I changed in my CIB? I checked that it does  
> compare it to the running CIB, and the IP address is not noted in the
> status section of the CIB. So how does ptest the job?

in the status section you'll find a whole lot of lrm_rsc_op "objects" ^
these represent a cluster operation and includes a number of fields  
that help us determine which order they were performed in and what  
parameters where used.

in particular, there is a field called "op_digest" which we use to  
detect changes to the resource's parameters

this is why I'm constantly asking people for their complete  
configuration... i need the status section :-)

^ as an example:

  <lrm_rsc_op id="child_DoFencing:5_monitor_120000"  
operation="monitor" crm-debug-origin="do_update_resource"  
call_id="35" crm_feature_set="2.0" rc_code="0" op_status="0"  
interval="120000" op_digest="20a63c39752cf941c02f4cba2a8a7b60"/>

> Thanks for any enlighting answer.
> Michael Schwartzkopff.
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