title: Bind-mount a host directory into a volume of a running docker container
body: <p>Let's say that I start a docker container with a bind-mounted local folder:</p>
  
  <pre><code>docker run --rm -v /ux1/dmtest:/data -it ubuntu
  </code></pre>
  
  <p>Then, locally - not inside the container, I bind-mount a directory from another fs into <code>/ux1/dmtest</code>:</p>
  
  <pre><code>mkdir /ux1/dmtest/bm
  mount --bind /ux0/bm /ux1/dmtest/bm
  </code></pre>
  
  <p>Now, from the container, I see <code>/data/bm/</code> and I can write content to it, but this content will not be visible on the host on <code>/ux0/bm</code>.</p>
  
  <p>Where is this content stored?
  And is there any way to mount additional storage into a running docker container (this workaround clearly doesn't work)?</p>