mlaunch: --kill to kill all mongod/s instances about mtools

[gianpaj]

I'm working on this at the moment.
https://github.com/gianpaj/mtools/commits/feature-killall

Just trying to understand why the mongos(es) don't seem to have lock file

[gianpaj]

I've found that the mongos doesn't have a .lock file so we need to start them with a --pidfile or connect to them and run db.shutdownServer()

Do you have any preference? opinion?

[rueckstiess]

Hey Gian, I'm glad you are taking this on, and sorry I haven't been thinking about this much yet.

Some thoughts:

On this page, it says

Without a specified pidfilepath, mongos creates no PID file.
Without this option, mongod creates no PID file.

So mongos should support it?

Alternatively, we know from the .mlaunch_startup what port the nodes were started on, and those show in a ps output. We could grep out the pids from there and kill it? We can also write more info into the .mlaunch_startup file if that would help?

[rueckstiess]

How these features should work (spec):

mlaunch --kill --dir <directory>

should find the instances that were started in <directory> and kill all of them (including mongos, config servers, mongod). Of course, just as with --restart, if the --dir argument is not given, it uses the default, the current working directory .. So this would work nicely when the user is already in the current directory, with just mlaunch --kill.

[gianpaj]

Exactly.
But I used --killall to specify that it will kill any process started on the specific directory.

And in the future we could do --kill configsrv, etc to kill specific ones.
Similarly to the syntax of #140 .