[CRIU] [PATCH v5 2/3] Do not error out in RPC mode with wrong config file entries

[Andrei Vagin]

On Fri, Dec 28, 2018 at 11:56:16PM +0000, Radostin Stoyanov wrote:
> On 28/12/2018 22:41, Andrei Vagin wrote:
> > On Thu, Dec 27, 2018 at 02:07:56PM +0000, Radostin Stoyanov wrote:
> >> On 26/12/2018 21:42, Andrei Vagin wrote:
> >>>> Relates: https://github.com/checkpoint-restore/criu/issues/578
> >>>>
> >>>> If the config parser finds a unknown option in the configuration file,
> >>>> the wrong option is printed out and CRIU exits.
> >>>>
> >>>> In RPC mode this is not the best thing to do, as CRIU might not be able
> >>>> to print the message to the user.
> >>> It is a bad explanation, because with your first patch the user will see
> >>> errors. I am not sure why we need to ignore unknown options in config
> >>> files. It looks dangerous, because the user can do a typo and will not
> >>> notice it.
> >>>
> >> A user could make a typo and they should be able to notice it in the log
> >> file but
> >> if CRIU exits with an error, this will break the checkpoint/restore
> >> functionality of
> >> container engines.
> >>
> >> An example of a software that has such behaviour is sshd. If a user
> >> makes a typo in
> >> the /etc/ssh/sshd_config file, after "systemctl restart sshd", they will
> >> no longer be
> >> able to connect via ssh. Although, for security reasons, the behaviour
> >> of sshd
> >> might be appropriate, I think that in the case of CRIU, showing a
> >> message, instead
> >> of exiting with an error, would be more user-friendly.
> > Yes and no. I understand the sshd reasons, but they can be applied to
> > criu restore, but not to criu dump, IMHO.
> >
> > Our goal is to not loose states of processes:
> > 1. criu dump doesn't have to be destructive:
> >   * in case of any error, processes have to continue running
> >   * it is better to fail rather than dump wrong or incomplete state
> >
> > 2. sometimes we really may want to restore processes even if there is
> > some problem
> That is a very good point, I agree with you.
> 
> Is it OK to close https://github.com/checkpoint-restore/criu/issues/578
> with the explanation above?

I would like to know what Adrian is thinking about this.
> 
> Thanks,
> Radostin