Working with OCI containers imported from dockerhub
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OverC can interact directly with docker registries, without requiring
docker as part of the image. These manipulations work whether the registry
is public (i.e. dockerhub) or private.

When interacting with docker registries the public APIs are used to
push/pull content, and then converted to OCI containers before executing
them on target. This conversion step allows security policies and other
integration steps to be seamlessly performed.

As part of the import process, OverC extracts the application entry
point (i.e. /sbin/init, or httpd) and any environment variables that
are required for the application. All other parts of the configuration
are controlled/set via the cube-cfg command.

Examples:
--------

  # pull something from docker hub
  % c3 add docker://httpd

  # if you want a different name than 'httpd' for the container
  % c3 add -n myhttpd docker://httpd

  # start the container
  % c3 start httpd

  # determine the 'netprime' of the system
  % netprime=$(c3 netprime)
  # 'c3 list' will also show this in table format

  # link port 8000 of the netprime to your container
  % c3-cfg link cube-server:8000 httpd:80
  # activat the link by stacking the container
  % c3 stack cube-server

  # set the container to autostart
  % c3-cfg -n httpd set autostart:dom0

  # push the container to your dockerhub
  % c3 stop httpd

  # authenticate and store
  % c3-cfg auth docker:
  # answer the prompts!
  % c3 store -n httpd docker://<username>/httpd

  % c3 add -n mycontainer docker://<my account>/mycontainer
  % c3 start mycontainer

Note:

If a container shows startup issues, the --foreground (or -f) flag
can be used to force container output to the launching terminal.

  % c3 start -f mycontainer

if your container daemonizes or runs in the background, only use this for
debugging.