On 2015/12/22 6:52, Eric W. Biederman wrote: > Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx> writes: > >> On 12/20/2015 05:47 PM, Eric W. Biederman wrote: >>> Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx> writes: >>> >>>> On 12/20/2015 10:37 AM, Al Viro wrote: >>>>> On Sun, Dec 20, 2015 at 10:14:29AM +0800, Dongsheng Yang wrote: >>>>>> On 12/17/2015 07:23 PM, Dongsheng Yang wrote: >>>>>>> Hi guys, >>>>>>> We are working on making core dump behaviour isolated in >>>>>>> container. But the problem is, the /proc/sys/kernel/core_pattern >>>>>>> is a kernel wide setting, not belongs to a container. >>>>>>> >>>>>>> So we want to add core_pattern into mnt namespace. What >>>>>>> do you think about it? >>>>>> >>>>>> Hi Eric, >>>>>> I found your patch about "net: Implement the per network namespace >>>>>> sysctl infrastructure", I want to do the similar thing >>>>>> in mnt namespace. Is that suggested way? >>>>> >>>>> Why mnt namespace and not something else? >>>> >>>> Hi Al, >>>> >>>> Well, because core_pattern indicates the path to store core file. >>>> In different mnt namespace, we would like to change the path with >>>> different value. >>>> >>>> In addition, Let's considering other namespaces: >>>> UTS ns: contains informations of kernel and arch, not proper for core_pattern. >>>> IPC ns: communication informations, not proper for core_pattern >>>> PID ns: core_pattern is not related with pid >>>> net ns: obviousely no. >>>> user ns: not proper too. >>>> >>>> Then I believe it's better to do this in mnt namespace. of course, >>>> core_pattern is just one example. After this infrastructure finished, >>>> we can implement more sysctls as per-mnt if necessary, I think. >>>> >>>> Al, what do you think about this idea? >>> >>> The hard part is not the sysctl. The hard part is starting the usermode >>> helper, in an environment that it can deal with. The mount namespace >>> really provides you with no help there. >> >> Do you mean the core dump helper? But I think I don't want to touch it >> in my development. I think I can use non-pipe way to get what I want, >> Let me try to explain what I want here. >> >> (1). introduce a --core-path option in docker run command to specify the >> path in host to store core file in one container. >> E.g: docker run --core-path=/core/test --name=test IMAGE >> >> (2). When the container starting, docker attach a volume to it, similar >> with "-v /core/test:/var/lib/docker/coredump". That means, the path of >> /var/lib/docker/coredump in container is a link to /core/test in host. >> >> (3). Set the /proc/sys/kernel/core_pattern in container as >> "/var/lib/docker/coredump". But that should not affect the core_pattern >> in host or other containers. >> >> Then I think I can collect the core files from each container and save >> them in the paths where I want. > > For your case that sounds like it would work. Unfortunately for this to > be generally applicable and to let the OS in the contianer control it's > fate the core dump pattern needs to be supported. > > Otherwise something clever in userspace that can be written now should > be sufficient to fill the gap. There is enough information for the user > mode helper to implement the policy you would like today. > Let me clarify my understanding. 1) running user-mode-helper in a container. It's not supported by the kernel. user-mode-helper always works on a host. 2) running user mode helper in a host. It's supported in the newest distro(FC23). (abrt supports container.) Summary is here. https://github.com/abrt/abrt/wiki/Containers-and-chroots If a guest user doesn't want to pass a core to the host owner, core_pattern should be configurable but it can't. Thanks, -Kame _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
