[lxc-users] ghost services on LXC containers

[Harald Dunkel]

On 8/13/20 12:32 PM, Fajar A. Nugraha wrote:
> Try (two times, once inside the container, once inside the host):
> - cat /proc/self/cgroup
> - ls -la /proc/self/ns

On the host:

root at il08:~# cat /proc/self/cgroup
13:name=systemd:/
12:rdma:/
11:pids:/
10:perf_event:/
9:net_prio:/
8:net_cls:/
7:memory:/
6:freezer:/
5:devices:/
4:cpuset:/
3:cpuacct:/
2:cpu:/
1:blkio:/
0::/
root at il08:~# ls -la /proc/self/ns
total 0
dr-x--x--x 2 root root 0 Aug 13 12:40 .
dr-xr-xr-x 9 root root 0 Aug 13 12:40 ..
lrwxrwxrwx 1 root root 0 Aug 13 12:40 cgroup -> 'cgroup:[4026531835]'
lrwxrwxrwx 1 root root 0 Aug 13 12:40 ipc -> 'ipc:[4026531839]'
lrwxrwxrwx 1 root root 0 Aug 13 12:40 mnt -> 'mnt:[4026531840]'
lrwxrwxrwx 1 root root 0 Aug 13 12:40 net -> 'net:[4026531992]'
lrwxrwxrwx 1 root root 0 Aug 13 12:40 pid -> 'pid:[4026531836]'
lrwxrwxrwx 1 root root 0 Aug 13 12:40 pid_for_children -> 'pid:[4026531836]'
lrwxrwxrwx 1 root root 0 Aug 13 12:40 time -> 'time:[4026531834]'
lrwxrwxrwx 1 root root 0 Aug 13 12:40 time_for_children -> 'time:[4026531834]'
lrwxrwxrwx 1 root root 0 Aug 13 12:40 user -> 'user:[4026531837]'
lrwxrwxrwx 1 root root 0 Aug 13 12:40 uts -> 'uts:[4026531838]'


Entering the container:

root at il08:~# lxc-attach -n il02
root at il02:~# cat /proc/self/cgroup
13:name=systemd:/
12:rdma:/
11:pids:/
10:perf_event:/
9:net_prio:/
8:net_cls:/
7:memory:/
6:freezer:/
5:devices:/
4:cpuset:/
3:cpuacct:/
2:cpu:/
1:blkio:/
0::/
root at il02:~# ls -la /proc/self/ns
total 0
dr-x--x--x 2 root root 0 Aug 13 12:42 .
dr-xr-xr-x 9 root root 0 Aug 13 12:42 ..
lrwxrwxrwx 1 root root 0 Aug 13 12:42 cgroup -> 'cgroup:[4026532376]'
lrwxrwxrwx 1 root root 0 Aug 13 12:42 ipc -> 'ipc:[4026532313]'
lrwxrwxrwx 1 root root 0 Aug 13 12:42 mnt -> 'mnt:[4026532311]'
lrwxrwxrwx 1 root root 0 Aug 13 12:42 net -> 'net:[4026532316]'
lrwxrwxrwx 1 root root 0 Aug 13 12:42 pid -> 'pid:[4026532314]'
lrwxrwxrwx 1 root root 0 Aug 13 12:42 pid_for_children -> 'pid:[4026532314]'
lrwxrwxrwx 1 root root 0 Aug 13 12:42 time -> 'time:[4026531834]'
lrwxrwxrwx 1 root root 0 Aug 13 12:42 time_for_children -> 'time:[4026531834]'
lrwxrwxrwx 1 root root 0 Aug 13 12:42 user -> 'user:[4026531837]'
lrwxrwxrwx 1 root root 0 Aug 13 12:42 uts -> 'uts:[4026532312]'


I am not sure what this is trying to tell me, though. Is this the same
hierarchy? And would you agree that this is really a bad thing to do?

Harri