On Fri, 2015-01-23 at 13:47 -0500, Stéphane Graber wrote: > On Fri, Jan 23, 2015 at 06:19:46PM +0000, Serge Hallyn wrote: > > Quoting Mathias Gibbens ([email protected]): > > > On Fri, 2015-01-23 at 00:48 +0000, Mathias Gibbens wrote: > > > > Hello, > > > > > > > > I've been testing LXC 1.1-rc1 on a Debian jessie system. Specifically, > > > > since all the pieces are now in place to support systemd in unprivileged > > > > containers, I've been testing running Debian jessie within an > > > > unprivileged container. > > > > > > > > The jessie container successfully starts (there are some errors along > > > > the way, but that's another issue), and I can do a `lxc-attach`, add a > > > > user and log in. However, if I run `top` within the container I only get > > > > two lines of output: > > > > > > > > top - 00:13:25 up 4 min, 0 users, load average: 0.01, 0.05, 0.05 > > > > Tasks: 10 total, 1 running, 9 sleeping, 0 stopped, 0 zombie > > > > > > > > Furthermore, the host system breaks spectacularly: > > > > > > > > lxc@lxc:~$ top > > > > Error, do this: mount -t proc proc /proc > > > > lxc@lxc:~$ /sbin/ifconfig > > > > Warning: cannot open /proc/net/dev (No such file or directory). Limited > > > > output. > > > > lxc@lxc:~$ mount > > > > mount: failed to read mtab: No such file or directory > > > > lxc@lxc:~$ df > > > > df: cannot read table of mounted file systems: No such file or directory > > > > lxc@lxc:~$ sudo reboot > > > > Running in chroot, ignoring request. > > > > > > > > It seems that /proc is being unmounted somehow on the host. I can > > > > re-mount /proc on the host, and things seem to work again. (I haven't > > > > tested too much after re-mounting, instead opting to just reboot the > > > > host back to a known good state.) > > > > > > > > Any idea what is causing this to happen? I have also tried running > > > > Ubuntu Vivid as an unprivileged container and see the same results. I > > > > have not yet tried a different Linux distro for the host system. > > > > > > > > Host system details: Debian jessie with kernel 3.16.7-ckt2-1 x86_64, > > > > systemd-215, LXC-1.1-rc1 and lxcfs built from current git checkout, > > > > cgmanager-0.35 as packaged from the sid repository. > > > > > > > > Thanks for any ideas, > > > > Mathias > > > > > > This morning I setup a host running Ubuntu Vivid with cgmanager, lxc, > > > and lxcfs packages installed from the daily PPA. I setup two > > > > But did you install the systemd-sysv package? > > > > > unprivileged containers, Debian jessie and Ubuntu Vivid, and ran `top` > > > within each one. On the Vivid host, `top` runs properly and the host > > > system does not break. > > > > > > So, it seems that the breakage is due to running jessie on the host > > > system. Any ideas why this is happening, or where I could begin looking > > > to debug this problem? > > > > No, I've just reproduced it, but it requires systemd to do so.
Ah, I had assumed that Vivid was using systemd by default, but didn't check. pid1 in Vivid still defaults to upstart. > > > > Note that you'll have to manually chown your name=systemd cgroup > > to your user for the lxc-start to succeed. > > > Hey, > > So we've just tracked down that bug and it's a critical flaw in lxcfs > which we've now fixed upstream. I tagged LXCFS 0.4 with the fix and am > publishing it now on our website and uploading it to Ubuntu. > > Thanks for reporting this! I can confirm that the fix in lxcfs resolves this issue and `top` now operates as expected without trashing the host system. Mathias
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