[Linux-ha-dev] Ordering of OCF Start, Stop and Monitor actions

[Doug Knight]

Thank you Alan, that explanation really helped. Would it be useful for
me to post my OCF script once its done and tested?

Doug

On Wed, 2007-03-21 at 19:13 -0600, Alan Robertson wrote:
> Doug Knight wrote:
> > Hi Andrew,
> > I had just started reviewing both of thes scripts, and reviewed the
> > Multistate and clone resource pages on the web site. It looks like
> > multistate is how I need to handle it, but a couple of questions first.
> > 
> > 1. I noticed that the write-up says the resource must come up on each of
> > the servers in "shadow" mode first, then one gets promoted. Does this
> > imply a "start" on both servers, and the OCF start function determining
> > which server is active vs shadow (I'm picturing a check in the OCF
> > script to determine postgresql standby mode = shadow/crm_master value
> > low, and postgresql active mode = active/crm_master value high), then a
> > promote to the active server?
> > 
> > 2. I noticed that the drbd OCF script contains a "notify" function,
> > where the Stateful OCF script does not. The notify function looks to be
> > where the important actions are taken (calling drbd_start_phase_2,
> > pre/post, etc). Is the notify function necessary, or is it sufficient in
> > my case to handle it through the start|stop|promote|demote functions?
> > 
> > Thanks for your help,
> > Doug
> 
> Andrew's out for a while.
> 
> The start function starts you up in slave/secondary mode.  All resources
> initially start up in "slave" mode.
> 
> A set of servers is chosen to run the resources on (it might be one,
> two, the whole set, etc. depending on clone_max and clone_node_max and
> the usual constraints).
> 
> They are started on the selected nodes using "start"
> 
> During the start operation, you are given the chance to declare yourself
> ready to become master or not by using the crm_master command line tool.
> 
> I believe that your resource can run that command any time they like -
> for example at a monitor operation...  But, it is mandatory that they
> run it when they first start up.
> 
> After this, heartbeat will try and promote as many of these resources as
> is consistent with its configured properties, and the crm_master
> commands that were run.
> 
> The notify command tells you when your peers come and go.  Do you need
> to take actions if you know this?
> 
> If so, then you need to implement the notify actions...
> 
> 
> 
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