[lxc-devel] lxc-start hangs when starting a new container

[Daniel Lezcano]

Matty wrote:
> On Wed, Jul 1, 2009 at 8:59 AM, Daniel Lezcano<dlezcano at fr.ibm.com> wrote:
>> Matty wrote:
>>> On Wed, Jul 1, 2009 at 4:12 AM, Daniel Lezcano<dlezcano at fr.ibm.com> wrote:
>>>> Matty wrote:
>>>>> I have an lxc container that keeps hanging when I run 'lxc-start -n
>>>>> <GUEST NAME>'. When I strace lxc-start, I see the following:
>>>>>
>>>>> $ strace lxc-start -n test
>>>>>  ..............
>>>>> open("/usr/local/var/lib/lxc/test/state", O_WRONLY) = 13
>>>>> flock(13, LOCK_EX)                      = 0
>>>>> ftruncate(13, 0)                        = 0
>>>>> write(13, "RUNNING"..., 7)              = 7
>>>>> close(13)                               = 0
>>>>> socket(PF_FILE, SOCK_DGRAM, 0)          = 13
>>>>> sendto(13,
>>>>> "\0\0\0\0test\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>>> 4104, 0, {sa_family=AF_FILE, path=@"lxc-monitor"...}, 110) = -1
>>>>> ECONNREFUSED (Connection refused)
>>>>> close(13)                               = 0
>>>>> close(13)                               = -1 EBADF (Bad file descriptor)
>>>>> close(14)                               = 0
>>>>> socket(PF_FILE, SOCK_STREAM, 0)         = 13
>>>>> bind(13, {sa_family=AF_FILE, path=@"test"...}, 110) = 0
>>>>> listen(13, 100)                         = 0
>>>>> fcntl(13, F_SETFD, FD_CLOEXEC)          = 0
>>>>> epoll_create(1)                         = 14
>>>>> epoll_ctl(14, EPOLL_CTL_ADD, 12, {EPOLLIN, {u32=17707440,
>>>>> u64=17707440}})
>>>>> = 0
>>>>> epoll_ctl(14, EPOLL_CTL_ADD, 13, {EPOLLIN, {u32=17707504,
>>>>> u64=17707504}})
>>>>> = 0
>>>>>
>>>>> I starting the container with 2.6.[29-31pre] kernels and with the
>>>>> latest lxc code, and they all appear to exhibit this behavior. Has
>>>>> anyone seen this before? Any idea what the lxc-monitor socket is used
>>>>> for?
>>>> can you give more information about the container itself ?
>>> Sure thing. This is a Fedora 11 container I created with lxc-fedora.
>>> Are there specific details you're after? If so, I will be glad to send
>>> them to you.
>>>
>>>> What is the configuration ?
>>> I used the defaults provided by lxc-fedora, though I disabled udev
>>> (commented out the udev line in rc.sysinit) to allow the container to
>>> boot.
>> Did you added the tty to the rootfs ?
>>
>> chroot rootfs.test1 /bin/bash
>> cd /dev
>> MAKEDEV tty
> 
> Hey Daniel,
> 
> I am bind mounting /dev into the container, so I would expect all of
> the devices to be there. In addition, I adjusted the cgroup
> permissions to allow me to access the most common devices:
> 
> devices.deny=a
> devices.allow=c 1:3 rwm
> devices.allow=c 1:5 rwm
> devices.allow=c 1:7 rwm
> devices.allow=c 1:8 rwm
> devices.allow=c 1:9 rwm
> devices.allow=c 5:0 rwm
> devices.allow=c 5:1 rwm
> devices.allow=c 5:2 rwm
> devices.allow=c 4:* rwm
> devices.allow=c 254:0 rwm
> 
> Shouldn't this work? Here is the fstab file I am using:
> 
> $  pwd
> /usr/local/var/lib/lxc/test
> 
> $ cat fstab
> /var/lxc/rootfs/test.rootfs /usr/local/var/lib/lxc/test/rootfs none rbind 0 0
> /dev /var/lxc/rootfs/test.rootfs/dev none bind 0 0
> 
>> After doing that, you can start the container again and check if you are
>> able to log to the container via lxc-console -n test1 command.
> 
> It still hangs in the same location. :(

I succeeded with the following:

devices.deny=a
devices.allow=c 1:* rwm
devices.allow=b 1:* rwm
devices.allow=b 3:* rwm
devices.allow=c 5:0 rwm
devices.allow=c 5:1 rwm
devices.allow=c 5:2 rwm
devices.allow=c 4:* rwm
devices.allow=c 254:0 rwm
devices.allow=b 254:* rwm
devices.allow=c 136:* rwm
devices.allow=c 10:62 rwm


Be careful, sharing /dev for a system container may lead to an 
unexpected behaviour :)

Thanks
   -- Daniel