I detected an issue with all Fedora 20 containers that may benefit from --nohangup workaround If I start the container without the "-d" flag, then I cannot enter the container via the console, later. If I start the container without the "-d" flag, it works, bu then I cannot get out.
So how do I try this workaround? If you give me precise instructions I will try it. Note: I have containers of 3 types, Debian, SLES and Fedora, only Fedora has the issue. Philip On Fri, May 9, 2014 at 9:56 AM, Dwight Engen <[email protected]> wrote: > On Fri, 9 May 2014 00:18:13 -0400 > Robert Pendell <[email protected]> wrote: > >> On Fri, May 9, 2014 at 12:12 AM, Robert Pendell >> <[email protected]> wrote: >> > On Thu, May 8, 2014 at 10:56 PM, Serge Hallyn >> > <[email protected]> wrote: >> >> Quoting Robert Pendell ([email protected]): >> >>> OS: Ubuntu 14.04 LTS x86_64 >> >>> Kernel: Host-Supplied 3.14.1 >> >>> Provider: Linode >> >>> Host Virtualization: Xen Paravirtualized >> >>> LXC Version: 1.0.3-0ubuntu3 >> >>> Guest: CentOS 6 i386 >> >>> >> >>> I know I've seen this issue crop up before however I don't know >> >>> how it has been fixed and the solution may vary. >> >>> >> >>> I'm using a standard Centos template created using the download >> >>> type. It is running in unprivileged mode and for some reason >> >>> lxc-console isn't producing any output when I attempt to connect >> >>> to it. >> >>> >> >>> Here is what I get: >> >>> shinji@icarus:~$ sudo lxc-console -n gateone >> >>> >> >>> Connected to tty 1 >> >>> Type <Ctrl+a q> to exit the console, <Ctrl+a Ctrl+a> to enter >> >>> Ctrl+a itself >> >> >> >> Before you run lxc-console, find the host pid of the mingetty on >> >> pts/1, and strace -f -p that one. >> >> >> > >> > Heh... I tried and it keeps telling me the process id doesn't exist >> > then I noticed that the pid is changing so I went into the guest and >> > looked at the messages log and it is being spammed with this... >> > >> > May 8 23:54:17 localhost init: tty (/dev/tty1) main process (2335) >> > terminated with status 1 >> > May 8 23:54:17 localhost init: tty (/dev/tty1) main process ended, >> > respawning May 8 23:54:17 localhost /sbin/mingetty[2348]: tty1: >> > vhangup() failed >> > >> > *a few minutes later* >> > Found the fix. This might have to go into the prep script for >> > CentOS as it seems to happen for others as well. It seems the >> > folks working on the Oracle image figured this out. >> > >> > https://github.com/lxc/lxc/blob/master/templates/lxc-oracle.in >> > Line 368 comments about how vhangup fails with userns. It probably >> > is related to unprivileged containers only although I have not >> > checked with privileged so don't quote me on that last bit. All I >> > know is it fixed the issue for me. Others may gain usefulness in >> > this. >> > >> > Basically I edited the /etc/init/tty.conf script and added >> > --nohangup to the mingetty exec command in the script. >> > >> > It became this: exec /sbin/mingetty $TTY --nohangup >> > >> > This will propagate to /dev/console as well due to the way that it >> > is being created during boot (it calls the tty init using >> > TTY=console as a parameter). >> >> Adding to my last message: >> https://github.com/lxc/lxc/commit/2e83f7201c5d402478b9849f0a85c62d5b9f1589 >> "This is needed when using the user namespace since the kernel check >> does not allow user_ns root to successfully call vhangup(2), and >> mingetty will quit in this case." >> >> So it does appear to only affect unprivileged containers. > > Hi Robert, yes its only when using user_ns. I added this as a > workaround because we never did figure out vhangup in a user_ns. See > http://comments.gmane.org/gmane.linux.kernel.containers.lxc.devel/2632 > for the original discussion. > >> _______________________________________________ >> lxc-users mailing list >> [email protected] >> http://lists.linuxcontainers.org/listinfo/lxc-users > _______________________________________________ > lxc-users mailing list > [email protected] > http://lists.linuxcontainers.org/listinfo/lxc-users _______________________________________________ lxc-users mailing list [email protected] http://lists.linuxcontainers.org/listinfo/lxc-users
