Verify the version of ubuntu running in a Docker container

The uname command is pulling specs from the kernel running on the host. If I enter a Ubuntu container on my Debian host, the uname will answer with a Debian build of the kernel.

To know the version of Ubuntu you are running, do a

$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.3 LTS"

It’s simple variables that are shell script friendly, so you can run

#!/bin/sh

if [ ! -f /etc/lsb-release ]; then
  echo "lsb-release missing, unlikely to be a Ubuntu system"
  exit 1
fi
. /etc/lsb-release
if [ "$DISTRIB_ID" != "Ubuntu" -o "$DISTRIB_RELEASE" != "16.04" ]; then
  echo "Linux install doesn't appear to be Ubuntu 16.04"
  exit 1
fi
...