Lab 1.2 Run a Container on Docker
=================================

.. seealso:: This is only a very basic introduction to docker. For everything
   else see `Docker Documentation <https://docs.docker.com/>`_

#. Continuing from where we left off on the jumpbox go back to the
   **kube-master1** session.

#. Now that docker is up and running and confirmed to be working lets deploy
   the latest `Apache web server <https://hub.docker.com/_/httpd/>`_.

   .. note:: The ``docker run`` command will first look for a local cache of
      the container **httpd**, and upon comparing that copy to the latest
      instance, decide to either download an update or use the local copy.
      Since there is no local copy, docker will download the container
      **httpd** to your local cache.  This can take a few seconds (or longer),
      depending on container size and your bandwidth. Docker will chunk this
      into parts called a pull.

      ``--rm`` "tells docker to remove the container after stopping"

      ``--name`` "give the container a memorable name"

      ``-d`` "tells docker to run detached. Without this the container would
      run in foreground and stop upon exit"

      ``-it`` "this allows for interactive process, like shell, used together
      in order to allocate a tty for the container process"

      ``-P`` "tells docker to auto assign any required ephemeral port and map
      it to the container"

   .. code-block:: bash

      docker run --rm --name "myapache" -d -it -P httpd:latest

#. If everything is working properly you should see your container running.

   .. note:: ``-f`` "lets us filter on key:pair"

   .. code-block:: bash

      docker ps -f name=myapache

   .. image:: images/docker-ps-myapache.png

   .. note:: The "PORTS" section shows the container mapping.  In this case the
      nodes local IP and port 32768 are mapped to the container.  We can use
      this info to connect to the container in the next step.

#. The httpd container "myapache, is running on kube-master1 (10.1.10.21) and
   port 32768. To test, connect to the webserver via chrome.

   .. code-block:: bash

      http://ip:port

   .. image:: images/myapache.png

.. attention:: That's it, you installed docker, downloaded a container, ran the
   Hello World container, ran a web server container, and accessed your web
   server container via the browser.