[lxc-users] fetching application update out of container's space

[Genco Yilmaz]

On Wed, Jun 10, 2015 at 11:06 PM, Tycho Andersen <
tycho.andersen at canonical.com> wrote:

> On Wed, Jun 10, 2015 at 09:22:10PM +0200, Genco Yilmaz wrote:
> > Hi,
> >    I have been playing with containers for a few days only and deployed
> > several to test some networking features. I have searched on the net to
> get
> > an answer but couldn't find any post/page yet. Issue is that I set up a
> > small LAB
> > containers of which has no internet access. If I need to install an
> > application e.g apache2
> > I attach to the container like;
> >
> > #lxc-attach -n container1
> > container1#apt-get install apache2
> >
> > but for this to work, I add a veth peer to let the container access
> outside
> > network (This isn't something I prefer to do as I need to isolate these
> > containers)
>
> Why not just run an apt mirror on the isolated network?
>
> > I wonder if there is any way to install this app from the master host i.e
> > by using master
> > host's network space but install the app on the container something like
> > this imaginary command;
> >
> > #*lxc-run* -n container -c "apt-get install apache2"
> >
> > i.e pulling the application from repository on the master space but
> pushing
> > it onto the container.
> >
> > There is lxc-execute, lxc-attach but they all run inside container's
> space
> > which doesn't work for me.
>
> You might like the -s option to lxc-attach.
>
> Tycho
>
> > Thanks,
> >
> > Genco.
>
>
Hi Tycho,
 Thanks for the reply. I have tried this one now. Apparently I didn't
notice this option:) but there seems to be an issue with name resolution.
Not sure what I am doing wrong though but although I am not attaching to
container's network namespace,
system still checks the resolv.conf file inside the container instead of
host's resolv.conf. As you can see,
if I add the nameserver to container resolv.conf, name resolution works. Is
this expected or there is a missing/incorrect option in my command? or is
it because of the MOUNT namespace. Because of this name resolution issue,
apt-get also fails



root at vhost3:~# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.2 LTS
Release:        14.04
Codename:       trusty

root at vhost3:~# ping archive.ubuntu.com -c 1
PING archive.ubuntu.com (91.189.91.15) 56(84) bytes of data.
64 bytes from likho.canonical.com (91.189.91.15): icmp_seq=1 ttl=51
time=81.6 ms

--- archive.ubuntu.com ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 81.607/81.607/81.607/0.000 ms

root at vhost3:~# lxc-attach -n LAB1016-co -e -s 'UTSNAME|MOUNT|PID|IPC' --
ping archive.ubuntu.com -c 1
ping: unknown host archive.ubuntu.com

root at vhost3:~# lxc-attach -n LAB1016-co -e -s 'UTSNAME|MOUNT|PID|IPC' --
ping 91.189.91.15 -c 1
PING 91.189.91.15 (91.189.91.15) 56(84) bytes of data.
64 bytes from 91.189.91.15: icmp_seq=1 ttl=51 time=80.7 ms

--- 91.189.91.15 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 80.739/80.739/80.739/0.000 ms

root at vhost3:~# cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by
resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 8.8.8.8
search example.com

root at vhost3:~# lxc-attach -n LAB1016-co
root at LAB1016-co:~# echo "nameserver 8.8.8.8" >> /etc/resolv.conf
root at LAB1016-co:~# exit
exit
root at vhost3:~# lxc-attach -n LAB1016-co -e -s 'UTSNAME|MOUNT|PID|IPC' --
ping archive.ubuntu.com -c 1
PING archive.ubuntu.com (91.189.91.14) 56(84) bytes of data.
64 bytes from orobas.canonical.com (91.189.91.14): icmp_seq=1 ttl=52
time=87.2 ms

--- archive.ubuntu.com ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 87.250/87.250/87.250/0.000 ms
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