Notes for KWLUG April 2016: Docker

Tim Laurence presented a docker workshop to KWLUG on April 4th 2016,

  • there will be an Ubuntu release party on April 23rd

  • this is a repeat of Tim's presentation to KWRuby in March (which I also have some notes on)

  • Tim reminded us that:

    • docker images are immutable
    • docker containers are mutable

  • docker images size list is confusing because images are based on shared images, so list does not show real disk usage

  • dockid is similar to a git commit hash, but it is just a random number

  • dockid is the canonical id, and the names are just for readability

  • rmi command to delete all images which are only used by the specified image

  • Docker < LXC < OpenVZ

  • run -rm runs a container deleted on exist

  • volumes can be mounted in multiple containers

  • in Dockerfile CMD needs an absolute path, where ADD does not