A service restart question

[likid0]

Hy,

I have a little doubt, that from what I read in the service guard manual doesn't give me a clear idea,

When you create a service on a package.

when you put in the service the -r 2 restart option so it restarts 2 times the aplication in case it fails, what does the cluster exactly do?

Does it run a:

Custom stop and Custom start ?
just a Custom start ?
or only it runs again the service_cmd )

I imagine the first, but could you confirm?

[melvyn burnard]

It will try to restart teh servcie 2 times, then consider it aq failure and halt the package on that node.
If the switching variables are then set correctly, the package will switch

[likid0]

Yes, but my doubt is, when it restart the service, what does it do?

stop start the hole package?

or just restart what you put in the service_cmd ?

because normaly what you have on the service_cmd is the monitor not the aplication

[melvyn burnard]

as it's name implies, it tries to restart the service, i.e. the monitor

[Sharma Sanjeev]

Hi

Yes it restart the Service not complete package

Regards
Sanjeev

[Emil Velez]

The system runs the package script with the halt option so it does try to halt gracefully unless you use the option "SERVICE_FAIL_FAST enabled" then the system does a panic TOC

[Deepak Kr · Accepted solution]

I hope you must have read in the same manual that serviceguard monitors the processes running in package applications using a script called package monitoring script.

This script keep on checking services and if any abruption or issue found with the state with service on current node it reads this paramters to restart service(s).

Depending on package switching parameters package gets shifted.

So in short, answer to your question is yes..it reads custom start..


regards,
deepak

[likid0]

So . let's say if your service is a monitor of the aplication.

lets say we have:


service=/app/app.sh monitor
custom start=/app/app.sh start
custom stop=/app/app.sh stop
and service restarts=3

so if a kill the app the monitor exits and dies, then a restart happens, and it's going to run again the monitor:

/app/app.sh monitor

and because my app is down because I killed it the monitor will exit again, because its not starting the app doing a /app/app.sh start.

So in the monitor script you need to put the app start ?


any of you have and example monitor a script for a simple app ?


Thnx

[Deepak Kr]

Hi,

Answer is it it will restart package. Whole bunch of services that are started using customer defined run commands.

On other hand if you are defining any service startup in customer defined run commands area then service you specify in service_cmd will get restarted.

Hope this will clear your doubt...

Regards,
Deepak

[likid0]

no, not really. i Still have the same question, If i put my monitor script on the service_cmd, and my app start script in the custom section, when the monitor dies how restarts my app?

[melvyn burnard]

Your application is NEVER restarted by the service, the service is simply a method of checking to see that vital processes or things are around so that the application is able to work.
A service restart simply tries to restart that monitoring IN CASE something prevented the monitor from verifying the required item(s) was actually available.


For example, the Oracle toolkit monitors to see whether specific processes are running, without which Oracle cannot work. If these fail, then the service fails, resulting in the package halting and being moved to another node.

[likid0]

Ok, Melvin understood, but then I have the next question, if you want to have your aplication restarted 2 times(for example), before stoping tha package and going to another node, which is the best way to do it?

[Masud Parvez]

Depend upon your application. If it is Oracle or SAP then not better to go for restart application service. If it is named or nfs then better use this.