[ClusterLabs] Oralsnr/Oracle resources agents

[Dejan Muhamedagic]

Hi,

On Sun, Feb 26, 2017 at 09:51:47AM +0300, Andrei Borzenkov wrote:
> 25.02.2017 23:18, Jihed M'selmi пишет:
> > [DM] I thought that oracle listener is not consuming that many resources.
> > At any rate, ocf:heartbeat:oralsnr doesn't support single listener for
> > multiple instances. Do you have an idea how to do that? How to deal with
> > the tnsping then? Maybe you're better off with the system start script in
> > this case.
> > 
> > [JM] According to the dba, it could lead some memory issue when the
> > listener serves many instances at the same time (in my experience, I have
> > never faced this issue).
> > 
> 
> What "it" means in the above sentence? "Running single listener for
> multiple instances" or "running each instance with own listener"?
> 
> How many instances are we talking about?
> 
> > Let's take a case when the listener is serving multiple instance, and one
> > of the instance fails => ocf:heartbeat:oracle will relocate it to another
> > node, the listener should follow (especially, when we use
> > collocation constraint between RA oracle and oralsnr) this will have a bad
> > impact on the rest of instances.
> > 
> > One of the option is to have two listeners (one per node) and configured
> > outside the cluster to host the all instance. But, I keep looking for a
> > better solution.
> > 
> > [DM] Hmm, what should then the RA do? Skip the instance and report it started?
> > I'm not sure I follow.
> > [JM] The DBA use a flag Y/N to tell if this instance should run or no. It
> > could be better, for RA to use this flag too: when it's Y start the
> > instance and when It's N, the RA should not start the instance and suitable
> > message in log will be usefull to describe the situation. Now, the
> > challenge is how to monitor this flag.
> > 
> 
> DBA still needs to remember to change this flag on each node in the
> cluster. In which case it can just as well remember to use different way
> to disable automatic startup.

Indeed. I wonder what is the difference between editing a file
and running say "crm rsc stop db".

At any rate, I doubt that there is a sane way for the RA to
handle such a case.

> > One of the issue that I faced when the DBA when to shutdown the listener
> > and the instance (for launch the cold backup) but, the RA keep pushing them
> > ON. -- Note the dba team usually don't have an access to pcs to disable the
> > resource during this type of operation.
> > 
> 
> There is nothing new. Once you put application under HA control, you in
> general cannot use native application tools to manage it. That is why
> SAP introduced "cluster glue" layer that intercepts native requests to
> start/stop application and forwards them to cluster for actual processing.
> 
> The solution here is really to make it possible to delegate control of
> individual resources to different users, so that DBA can
> start/stop/disable/unmanage individual resources (s)he owns.
> 
> If nothing else, it can be done as SUID scripts that implement this check.

Users other than root/hacluster can be given access to cluster
(essentially editing the CIB). Details escape me now, but there
is a concept of roles and then one can define rules on what roles
are allowed to do.

Thanks,

Dejan

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