Creating Linux Test Environments using Docker

Authors: Arun Ramanathan & Pavankumar Mudalagi

Assume you need to deploy 10 SLES 11 SP3 machines. The most common run of the mill way we use is to deploy 10 Linux servers in an ESX host machine or Virtual Box or XEN server. The only drawback is we need to clone and install these Linux desktops at least 9 times which is time consuming. Do we have an alternative?

Yes we do!

First install your Base Linux Machine. I installed openSUSE 13.2 (Harlequin) (x86_64)

Deploying SLES 11 SP3 Container with Docker

Step 1: Download SLES 11 SP3 images.

• Signup in https://hub.docker.com/
• Search for SLES 11 SP3
• Select your image, we selected gbeutner/sles-11-sp3-x86_64 since it had large number of pull.

  

• Above Image can be pulled from Docker’s central index at http://index.docker.io using the command:

# docker pull gbeutner/sles-11-sp3-x86_64

• Verify the image is downloaded.

  # docker images
  
  REPOSITORY                   TAG	IMAGE ID       CREATED        VIRTUAL SIZE
  gbeutner/sles-11-sp3-x86_64  latest	22de129c1cdd   10 months ago  193.1 MB

Step 2: Run this Image with an IMAGE ID “22de129c1cdd” :

#docker run -i -t 22de129c1cdd /bin/bash
ebf803aaabe9:/ # ----> it will open a new bash prompt

Step 3: Install and configure all required software in this image. In my case I needed Go Programming language.

Step 4: In a new Terminal of OpenSUSE 13.2, commit the container.

ebf803aaabe9:/# mkdir -p /home/Golang ; cd /home/Golang
ebf803aaabe9:/home/Golang # scp fa.ke.ad.dr:/home/Golang/go1.4.2.linux-amd64.tar.gz /home/Golang/
ebf803aaabe9:/home/Golang # tar -xvzf go1.4.2.linux-amd64.tar.gz

Get Container ID.

# docker ps

CONTAINER ID   IMAGE                 COMMAND       CREATED          STATUS         PORTS     NAMES
ebf803aaabe9   22de129c1cdd:latest   "/bin/bash"   9 minutes ago    Up 9 minutes             reverent_blackwell

Commit the image using Container ID.

# docker commit ebf803aaabe9

Step 5: Clone and Run the images.

First, get the list of images

# docker images
REPOSITORY			TAG		IMAGE ID	CREATED		VIRTUAL SIZE
<none>				<none>		9d36165e91df	2 minutes ago	485 MB
gbeutner/sles-11-sp3-x86_64	latest		22de129c1cdd	10 months ago	193.1 MB

In 10 new SSH terminals, run the latest Image with Image ID “9d36165e91df” to get 10 unique SLES 11 machine.

# docker run -i -t 9d36165e91df /bin/bash

To see list of Running Containers

# docker ps
CONTAINER ID   IMAGE         	     COMMAND       CREATED          STATUS          PORTS   NAMES
62382eed12af   9d36165e91df:latest   "/bin/bash"   14 seconds ago   Up 14 seconds           adoring_mayer

To close a Running Container say with Container ID “62382eed12af“

62382eed12af:/ # exit
Exit

Conclusion: If you want a quicker way to deploy Linux / Windows machines, it’s time to move to Docker. You can save many man hours with it!

References:
https://docs.docker.com/reference/commandline/cli/
https://www.suse.com/documentation/sles-12/singlehtml/dockerquick/dockerquick.html