[libvirt] simple LXC/libvirt busybox container (Unable to get cgroup)

[Daniel P. Berrange]

On Thu, Dec 10, 2009 at 02:22:37AM -0600, Tony Risinger wrote:
> i'm trying to get even the simplest busybox container with libvirt+LXC
> with very limited success.  I feel l am missing something supremely
> simple for me to be hung on this for weeks.
> 
> i dont see anything interesting in domain log, but getting this error
> from "LIBVIRT_DEBUG=1 libvirtd":
> 
> 05:27:56.113: error : lxcDomainGetInfo:462 : internal error Unable to
> get cgroup for arch-nano
> 05:27:56.113: debug : virDomainFree:2004 : domain=0x81d8e68
> 05:27:56.113: debug : virUnrefDomain:422 : unref domain 0x81d8e68 arch-nano 1
> 05:27:56.113: debug : virReleaseDomain:376 : release domain 0x81d8e68 arch-nano
> 05:27:56.113: debug : virReleaseDomain:392 : unref connection 0x81dc0f0 2
> 05:27:56.113: debug : remoteSerializeError:141 : prog=536903814 ver=1
> proc=16 type=1 serial=4, msg=internal error Unable to get cgroup for
> arch-nano
> 
> i've been using this root filesystem layout:
> 
> [root at PHS-001 arch-nano]# tree
> .
> |-- bin
> |   |-- cat -> ../sbin/busybox
> |   |-- chdir -> ../sbin/busybox
> |   |-- chmod -> ../sbin/busybox
> |   |-- ls -> ../sbin/busybox
> |   |-- rm -> ../sbin/busybox
> |   |-- sh -> ../sbin/busybox
> |   `-- vi -> ../sbin/busybox
> |-- dev
> |   `-- pts
> |-- etc
> |-- proc
> |-- sbin
> |   |-- busybox
> |   `-- init -> busybox
> `-- sys
> 
> all folders besides /bin and /sbin were created by libvirt.  i tried
> using the /sbin/init script previously suggested:
> 
> #!/sbin/busybox
> sh


Sorry, my suggestion was wrong. I forgot that if you have #!/sbin/busybox
it will attempt to execute the command matching the name of the script.
So it will in fact try to run 'init', rather than 'sh'. 

Just make the libvirt XML point directly to /bin/sh  instead and it
should work. I even tested it this time :-)

> but i get a similar results either way (script/symlink):
> 
>  8173 ?        Ss     0:00 /usr/lib/libvirt-git/libvirt_lxc --name
> arch-nano --console 11 --background
>  8175 pts/0    Ss+    0:00 init
>  8177 ?        Ss     0:00 init
>  8181 ?        Zs     0:00 [init] <defunct>
>  8182 ?        Zs     0:00 [init] <defunct>
>  8183 ?        Zs     0:00 [init] <defunct>

Yeah this is what I see too, when i have /sbin/init - changing it to
/bin/sh works


Daniel
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