title: Running Docker on Ubuntu docker image
body: <p>I'm having trouble getting Docker CE to run on an Ubuntu Docker image. Here's my <code>Dockerfile</code>:</p>
  
  <pre><code>FROM ubuntu:16.04
  
  RUN apt-get update &amp;&amp; apt-get install -y curl apt-transport-https ca-certificates curl gnupg2 software-properties-common
  RUN curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -
  RUN add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
  RUN apt-get update &amp;&amp; apt-get install -y docker-ce
  
  RUN docker info
  </code></pre>
  
  <p>The last command fails with the following:</p>
  
  <p><code>Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?</code></p>
  
  <p>If I attempt to run <code>dockerd</code> from the container, it comes back with the following:</p>
  
  <pre><code>ERRO[2018-04-12T14:35:43.945962200Z] 'overlay2' is not supported over overlayfs
  INFO[2018-04-12T14:35:43.974187900Z] Graph migration to content-addressability took 0.00 seconds
  INFO[2018-04-12T14:35:43.976355700Z] Loading containers: start.
  WARN[2018-04-12T14:35:43.978060300Z] Running modprobe bridge br_netfilter failed with message: , error: exec: "modprobe": executable file not found in $PATH
  WARN[2018-04-12T14:35:43.978173000Z] Running modprobe nf_nat failed with message: ``, error: exec: "modprobe": executable file not found in $PATH
  WARN[2018-04-12T14:35:43.978965200Z] Running modprobe xt_conntrack failed with message: ``, error: exec: "modprobe": executable file not found in $PATH
  Error starting daemon: Error initializing network controller: error obtaining controller instance: failed to create NAT chain: iptables failed: iptables -t nat -N DOCKER: iptables v1.6.0: can't initialize iptables table `nat': Permission denied (you must be root)
  Perhaps iptables or your kernel needs to be upgraded.
   (exit status 3)
  </code></pre>
  
  <p>I assume there is something missing in the kernel for the <code>ubuntu</code> image?</p>
  
  <p>Here's the output of <code>uname -a</code>, from the container:</p>
  
  <pre><code>root@85bdefe67e4a:/# uname -a
  Linux 85bdefe67e4a 4.9.87-linuxkit-aufs #1 SMP Wed Mar 14 15:12:16 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
  </code></pre>
  
  <p>Is it something wrong with the <code>ubuntu:16.04</code> container or is there something I'm forgetting?</p>