Listing 1. The last three lines show Docker's special mount trick, so
containers get information from Docker-managed host files.

<programlisting>
root@4de393bdbd36:/var/www/html# findmnt -o TARGET,SOURCE
TARGET                  SOURCE
/                       /dev/mapper/docker-8:2-25824189-4de...822[/rootfs]
|-/proc                 proc
| |-/proc/sys           proc[/sys]
| |-/proc/sysrq-trigger proc[/sysrq-trigger]
| |-/proc/irq           proc[/irq]
| |-/proc/bus           proc[/bus]
| `-/proc/kcore         tmpfs[/null]
|-/dev                  tmpfs
| |-/dev/shm            shm
| |-/dev/mqueue         mqueue
| |-/dev/pts            devpts
| `-/dev/console        devpts[/2]
|-/sys                  sysfs
|-/etc/resolv.conf
/dev/sda2[/var/lib/docker/containers/4de...822/resolv.conf]
|-/etc/hostname         /dev/sda2[/var/lib/docker/containers/4de...822/hostname]
`-/etc/hosts            /dev/sda2[/var/lib/docker/containers/4de...822/hosts]