On 12/22/2015 11:12 AM, Kamezawa Hiroyuki wrote: > On 2015/12/22 6:52, Eric W. Biederman wrote: >> Dongsheng Yang <yangds.f...@cn.fujitsu.com> writes: >> >>> On 12/20/2015 05:47 PM, Eric W. Biederman wrote: >>>> Dongsheng Yang <yangds.f...@cn.fujitsu.com> 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.
Agreed, then we have to make the core_pattern namespace-ed in mnt namespace. Thanx Yang > > Thanks, > -Kame > > > > > . > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
