Docker

tutorial_1.sh

$ sudo docker run ubuntu:14.04 /bin/echo 'Hello world'

# The -t flag assigns a pseudo-tty or terminal inside our new container and the -i flag allows us to make an interactive connection by grabbing the standard in (STDIN) of the container.
$ sudo docker run -t -i ubuntu:14.04 /bin/bash

# A Daemonized Hello world
$ sudo docker run -d ubuntu:14.04 /bin/sh -c "while true; do echo hello world; sleep 1; done"
1e5535038e285177d5214659a068137486f96ee5c2e85a4ac52dc83f2ebe4147

$ sudo docker ps
CONTAINER ID  IMAGE         COMMAND               CREATED        STATUS       PORTS NAMES
1e5535038e28  ubuntu:14.04  /bin/sh -c 'while tr'  2 minutes ago  Up 1 minute        insane_babbage

$ sudo docker logs insane_babbage
hello world
hello world
hello world
. . .

# stop
$ sudo docker stop insane_babbage
insane_babbage

# Running a Web Application in Docker
$ sudo docker run -d -P training/webapp python app.py

$ sudo docker ps -l
CONTAINER ID  IMAGE                   COMMAND       CREATED        STATUS        PORTS                    NAMES
bc533791f3f5  training/webapp:latest  python app.py 5 seconds ago  Up 2 seconds  0.0.0.0:49155->5000/tcp  nostalgic_morse

# bind to specific port
$ sudo docker run -d -p 5000:5000 training/webapp python app.py

$ sudo docker port nostalgic_morse 5000
0.0.0.0:49155

$ sudo docker logs -f nostalgic_morse
* Running on http://0.0.0.0:5000/
10.0.2.2 - - [23/May/2014 20:16:31] "GET / HTTP/1.1" 200 -
10.0.2.2 - - [23/May/2014 20:16:31] "GET /favicon.ico HTTP/1.1" 404 -

$ sudo docker top nostalgic_morse
PID                 USER                COMMAND
854                 root                python app.py

$ sudo docker inspect nostalgic_morse
[{
    "ID": "bc533791f3f500b280a9626688bc79e342e3ea0d528efe3a86a51ecb28ea20",
    "Created": "2014-05-26T05:52:40.808952951Z",
    "Path": "python",
    "Args": [
       "app.py"
    ],
    "Config": {
       "Hostname": "bc533791f3f5",
       "Domainname": "",
       "User": "",
. . .

$ sudo docker inspect -f '{{ .NetworkSettings.IPAddress }}' nostalgic_morse
172.17.0.5

$ sudo docker stop nostalgic_morse
nostalgic_morse

# restart container
$ sudo docker start nostalgic_morse
nostalgic_morse

# remove container
$ sudo docker stop nostalgic_morse
nostalgic_morse

$ sudo docker rm nostalgic_morse
nostalgic_morse

tutorial_2.sh

# Listing images on the host
$ sudo docker images

# Getting a new image
$ sudo docker pull centos

$ sudo docker run -t -i centos /bin/bash
bash-4.1#

# Search for image
$ sudo docker search sinatra

# Creating our own images
# 1) We can update a container created from an image and commit the results to an image.
    $ sudo docker run -t -i training/sinatra /bin/bash
    $ root@0b2616b0e5a8:/# gem install json
    $ sudo docker commit -m="Added json gem" -a="Kate Smith" 0b2616b0e5a8 ouruser/sinatra:v2
    # try the new image
    $ sudo docker run -t -i ouruser/sinatra:v2 /bin/bash

# 2) We can use a Dockerfile to specify instructions to create an image.
    $ mkdir sinatra
    $ cd sinatra
    $ touch Dockerfile
    $ cat Dockerfile
    # This is a comment
    FROM ubuntu:14.04
    MAINTAINER Kate Smith <[email protected]>
    RUN apt-get update && apt-get install -y ruby ruby-dev
    RUN gem install sinatra
    
    $ sudo docker build -t="ouruser/sinatra:v2" .
    
    # Create a container from the new image
    $ sudo docker run -t -i ouruser/sinatra:v2 /bin/bash
    root@8196968dac35:/#
    
    # Setting tags on an image
    $ sudo docker tag 5db5f8471261 ouruser/sinatra:devel
    
# Push an image to Docker Hub
$ sudo docker push ouruser/sinatra

# Remove an image from the host
$ sudo docker rmi training/sinatra

tutorial_3.sh

# To bind port 5000 of the container to a dynamic port but only on the localhost, you could use:
$ sudo docker run -d -p 127.0.0.1::5000 training/webapp python app.py

# You can also bind UDP ports by adding a trailing /udp. For example:
$ sudo docker run -d -p 127.0.0.1:5000:5000/udp training/webapp python app.py

$ sudo docker port nostalgic_morse 5000
127.0.0.1:49155

# Linking Containers Together
# Container naming
$ sudo docker run -d -P --name web training/webapp python app.py

$ sudo docker ps -l
CONTAINER ID  IMAGE                  COMMAND        CREATED       STATUS       PORTS                    NAMES
aed84ee21bde  training/webapp:latest python app.py  12 hours ago  Up 2 seconds 0.0.0.0:49154->5000/tcp  web

$ sudo docker inspect -f "{{ .Name }}" aed84ee21bde
/web

# Container Linking
$ sudo docker run -d --name db training/postgres
$ sudo docker run -d -P --name web --link db:db training/webapp python app.py
$ sudo docker inspect -f "{{ .HostConfig.Links }}" web
[/db:/web/db]
# Docker exposes connectivity information for the source container to the recipient container in two ways:
# 1) Environment variables,
    $ sudo docker run --rm --name web2 --link db:db training/webapp env
    . . .
    DB_NAME=/web2/db
    DB_PORT=tcp://172.17.0.5:5432
    DB_PORT_5432_TCP=tcp://172.17.0.5:5432
    DB_PORT_5432_TCP_PROTO=tcp
    DB_PORT_5432_TCP_PORT=5432
    DB_PORT_5432_TCP_ADDR=172.17.0.5
    . . .
# 2) Updating the /etc/hosts file.
    $ sudo docker run -t -i --rm --link db:db training/webapp /bin/bash
    root@aed84ee21bde:/opt/webapp# cat /etc/hosts
    172.17.0.7  aed84ee21bde
    . . .
    172.17.0.5  db
    
    root@aed84ee21bde:/opt/webapp# apt-get install -yqq inetutils-ping
    root@aed84ee21bde:/opt/webapp# ping db
    PING db (172.17.0.5): 48 data bytes
    56 bytes from 172.17.0.5: icmp_seq=0 ttl=64 time=0.267 ms
    56 bytes from 172.17.0.5: icmp_seq=1 ttl=64 time=0.250 ms
    56 bytes from 172.17.0.5: icmp_seq=2 ttl=64 time=0.256 ms

tutorial_4

# Managing Data in Containers
# 1) Data volumes
    # A data volume is a specially-designated directory within one or more containers that bypasses
    # the Union File System to provide several useful features for persistent or shared data:
    
    $ sudo docker run -d -P --name web -v /webapp training/webapp python app.py
    
    # Mount a Host Directory as a Data Volume
    $ sudo docker run -d -P --name web -v /src/webapp:/opt/webapp training/webapp python app.py
    
    # Mount a Host File as a Data Volume
    $ sudo docker run --rm -it -v ~/.bash_history:/.bash_history ubuntu /bin/bash

# 2) Data Volume Container
    # If you have some persistent data that you want to share between containers, or want to use from non-persistent containers, 
    # it's best to create a named Data Volume Container, and then to mount the data from it.
    
    $ sudo docker run -d -v /dbdata --name dbdata training/postgres echo Data-only container for postgres
    $ sudo docker run -d --volumes-from dbdata --name db1 training/postgres
    $ sudo docker run -d --volumes-from dbdata --name db2 training/postgres
    $ sudo docker run -d --name db3 --volumes-from db1 training/postgres
    
    # Backup, restore, or migrate data volumes
    $ sudo docker run --volumes-from dbdata -v $(pwd):/backup ubuntu tar cvf /backup/backup.tar /dbdata
    $ sudo docker run -v /dbdata --name dbdata2 ubuntu /bin/bash
    $ sudo docker run --volumes-from dbdata2 -v $(pwd):/backup busybox tar xvf /backup/backup.tar