restart (mktree) program usage

Sukadev Bhattiprolu sukadev at linux.vnet.ibm.com
Tue Sep 8 22:56:36 PDT 2009


I have a usage question on the 'restart' (formerly mktree) program.

In the following container c/r case: 

	- create a container
	- log in to the container,
	- restore filesystem(s) from snapshot
	- restart application from checkpoint

On restart, suppose the user wants to restore the original pids.
But he does not want to create a new pid-ns, (since he just created
the container, and is sure the original pids are available).

To accomplish this the user has to specify the arguments in the following
order right  (since -pids implies --pidns).

	restart --pids --no-pidns

IOW, the order of the arguments matters.

Would it be easier to understand if --pids did not imply --pidns ?

(Or in fact the reverse seems to make more sense -i.e --pidns implies
--pids, with a new option, --no-pids if user absolutely hates the pids
he was dealt before checkpoint :-)

	$ restart
		don't create pid ns, don't try to restore pids

	$ restart --pids
		try to restore original pids, don't create pid-ns

	$ restart --pidns
		create new pid-namespace and restore original pids

	$ restart --pidns --no-pids
	$ restart --no-pids --pidns
		create new pid-namespace, DO NOT restore pids

Or maybe drop implying and let user explicitly specify one, none or
both of --pids, --pidns ?

Sukadev


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