Unable to ping from inside container

[percy78]

@cyphar

Hi, this has obviously been addressed earlier but unfortunately I have tested all to no avail.

The issue suddenly just appeared after a restart of my Nagios docker container, hence the issue as check_ping is invoked by the nagios user. What happened was that my docker storage /var/lib/docker almost got full. I therefore added a new drive on to my Ubuntu host and created a new LVM volume to cater for Docker. I stopped all the containers and then tared /var/lib/docker to the new volume. Then I restarted my nagios container and all of sudden this issue appeared, it's been working fine for over 2 years so not sure what's happened here.

Started the container with these parameters:

root@nobsphp01:~# docker run --cap-add net_raw --cap-add net_admin -d -p 25:25 -p 80:80 quantumobject/docker-nagios_prod:version2.5

root@fb8792fa7dc2:/# su - nagios
$ ping nobux20
ping: icmp open socket: Operation not permitted

root@fb8792fa7dc2:/# ls -latr /bin/ping
-rwsr-xr-x 1 root root 64424 Mar 9 2017 /bin/ping

Have you got any ideas?