Containers

1. Login to the Docker registry docker-stage.liatr.io

   Solution

   docker login docker-stage.liatr.io
   

   Example Output:

   [user12@VM:dojo-sandbox ~]$ docker login docker-stage.liatr.io
   Username: user12
   Password: *************
   Login Succeeded
   

2. Pull down the nodejs image from docker-stage.liatr.io found at /repo/nodejs10 with tag 1.0.0

   Solution

   docker pull docker-stage.liatr.io/repo/nodejs10:1.0.0
   

   Example Output:

   [user12@VM:dojo-sandbox ~]$ docker pull docker-stage.liatr.io/repo/nodejs10:1.0.0
   Trying to pull repository docker-stage.liatr.io/repo/nodejs10 ... 
   1.0.0: Pulling from docker-stage.liatr.io/repo/nodejs10
   d69140bdce18: Pull complete 
   a82dd37af30d: Pull complete 
   bf4a6f4593f2: Pull complete 
   f8c91665e5ce: Pull complete 
   95d1c15ed2d1: Pull complete 
   fe908ec87177: Pull complete 
   dc37faa77625: Pull complete 
   08c6e439e8ee: Pull complete 
   b2475b29510d: Pull complete 
   796ad60e2332: Pull complete 
   cb86202e581e: Pull complete 
   f30d62cd2e8b: Pull complete 
   Digest: sha256:6bc3a2922cdd82b75b2f2f34e47aef08ad49031024f64e7e8625c706d1ac0c74
   Status: Downloaded newer image for docker-stage.liatr.io/repo/nodejs10:1.0.0
   

   If you notice the number of 'pulls' it completed, it completed 12 of them. Why is that? That's because it pulls down each layer individually. There are 12 layers to this nodejs image.

3. Try to run the nodejs image you just pulled down. Then list all running and exited containers.

   Solution

   docker run docker-stage.liatr.io/repo/nodejs10:1.0.0
   

   docker ps -a
   

   Example Output

   [user12@VM:dojo-sandbox ~]$ docker run docker-stage.liatr.io/repo/nodejs10:1.0.0
   [user12@VM:dojo-sandbox ~]$ docker ps -a
   CONTAINER ID        IMAGE                                                   COMMAND             CREATED             STATUS                     PORTS               NAMES
   3d1bfd34cb32        docker-stage.liatr.io/repo/nodejs10:1.0.0   "/bin/bash"         4 seconds ago       Exited (0) 3 seconds ago                       hungry_joliet
   

   You'll notice that the command exited after 3 seconds. Why? Because there was no executable command inside the container. It started, had nothing to do, so it shut down.

4. Try running the image again with the -i and -t options telling it to run a /bin/bash command. If you are successful you should find yourself inside the running container. Take a look inside if you'd like. Run exit to escape from the container.

   Solution

   [user12@VM:dojo-sandbox ~]$ docker run -i -t docker-stage.liatr.io/repo/nodejs10:1.0.0 /bin/bash
   [jnpr@7d43450ee7c8 /]$ pwd
   /
   [jnpr@7d43450ee7c8 /]$ ls
   bin  boot  dev  etc  home  lib  lib64  media  mnt  node_modules  opt  proc  root  run  sbin  srv  sys  tmp  usr  var
   [jnpr@7d43450ee7c8 /]$ exit
   exit
   [user12@VM:dojo-sandbox ~]$ 
   

5. Clear Docker containers and Docker images

   Clean up any Docker containers that are not running and all Docker images not associated with a running container

   Solution

   docker rm $(docker ps -a -q)
   

   docker image prune -a
   

   Example Output:

   [user12@VM:dojo-sandbox ~]$ docker rm $(docker ps -a -q)
   7d43450ee7c8
   3d1bfd34cb32
   [user12@VM:dojo-sandbox ~]$ docker image prune -a
   WARNING! This will remove all images without at least one container associated to them.
   Are you sure you want to continue? [y/N] y
   Deleted Images:
   untagged: docker-stage.liatr.io/repo/nodejs10:1.0.0
   untagged: docker-stage.liatr.io/repo/nodejs10@sha256:6bc3a2922cdd82b75b2f2f34e47aef08ad49031024f64e7e8625c706d1ac0c74
   deleted: sha256:78bff9d1a474cf1b931c5c4c948a4998463e4c1bb28de6224673287c8baa6d62
   deleted: sha256:60030f89badfaf2467928c2ce5d1a0e3a5cb3df669352cd4f92334eb7bbe82a4
   deleted: sha256:ccb55c3c59a69d4b6474c02d4d77b9177789c87ac48cd3178433d16bf12f2fae
   deleted: sha256:4f0407d9ddbc8c96d1464a0d5f3bfd6ad7976ca91368281b5a155742a1a18c01
   deleted: sha256:f50464cb3b027c2b21ab88fed1024b5912e9cdb745fc2524966db6f0cb53f807
   deleted: sha256:062f2c15b6c1c30aa2762be4526dd21edf7e989585925a31f20a9a7953a5d112
   deleted: sha256:0535d3c162a39caf2a9e99dfc8af34f9f0c62ebd01af95ab9a4b8d84b177d12c
   deleted: sha256:be919eed8b21a340b1cbd7c84470ba3f2e8220fa13f518aab6f541f7924e7f8c
   deleted: sha256:1a909fa3db3f667c5784c200735c2858ac84523b566c6f4077f603bd4fb83723
   deleted: sha256:9afeae4d34d0369cbc5695e3c185e224040bd2c6c068d78a68a76b413444cfa1
   deleted: sha256:2467b4f9cb944fe1c0ea60d1d1a450af6922a349da84ea13e5ef2794e366a47c
   deleted: sha256:d8298763f7d9aed4cfb2e38a964b9ec8358d9ff3c67b6539bc468fd3c1dd701a
   deleted: sha256:03b8aa00f0018b0d0eb70a535c71c87da3bd7810bc7d5fb1ec5237b7aaf0a0cb
   
   Total reclaimed space: 1.01 GB
   [user12@VM:dojo-sandbox ~]$