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Changes coming for systemd and control groups

Changes coming for systemd and control groups

Posted Jun 23, 2013 15:21 UTC (Sun) by marcH (subscriber, #57642)
In reply to: Changes coming for systemd and control groups by zblaxell
Parent article: Changes coming for systemd and control groups

I really feel like you could have made your point more clearly in 3 times less messages, themselves 5 times shorter. Unfortunately a bit too late to rescue the S/N ratio of this thread now...

So, you seem to have a use case where you want to stop a cgroup not entirely but partially, leaving some child process(es) alive. Is this really what this is all about? If yes can you give actual example(s)?

I totally agree that default settings do matter and changing them is almost always bad: a serious break of backward compatibility. In this case however the previous, ages-old default was more a limitation caused by the lack of cgroups than a conscious decision.


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Changes coming for systemd and control groups

Posted Jul 2, 2013 20:55 UTC (Tue) by zblaxell (subscriber, #26385) [Link]

In this case however the previous, ages-old default was more a limitation caused by the lack of cgroups than a conscious decision."
Things like SIGHUP, session leaders, process groups and the nohup command existed long before systemd. If a process wanted to stick around after it has been asked to exit (perhaps disassociating itself from resources as it does so), it had standard mechanisms to do so until systemd came along.

Changes coming for systemd and control groups

Posted Jul 2, 2013 23:11 UTC (Tue) by Cyberax (✭ supporter ✭, #52523) [Link]

So disable them. What's the problem?

The process group mess is a historic Unix f*up, along with the controlling terminals and the whole TTY system.

And if you have a nohuped process that can lose the data if someone SIGKILLs it then you certainly deserve it, unless you use it for one-off activity.

Changes coming for systemd and control groups

Posted Jul 3, 2013 14:00 UTC (Wed) by zblaxell (subscriber, #26385) [Link]

My point is that the ages-old implementors did have the option of doing drive-by fatal mass-signalling of processes that happened to be descendants (many generations removed) of server daemons or session processes spawned for TTY or network connections.

They chose to do things differently from systemd when they had the opportunity and technical capacity to do a similar implementation, and they had sound reasons for making the choices they did.


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