Docker Volumes Mapping

 Question : The Nautilus DevOps team is testing applications containerization, which issupposed to be migrated on docker container-based environments soon. In today's stand-up meeting one of the team members has been assigned a task to create and test a docker container with certain requirements. Below are more details:

a. On App Server 3 in Stratos DC pull ubuntu image (preferably latest tag but others should work too).

b. Create a new container with name media from the image you just pulled.

c. Map the host volume /opt/dba with container volume /var. There is an sample.txt file present on same server under /tmp; copy that file to /opt/dba. Also please keep the container in running state.

Please Note:-  Perform the below commands based on your question server,  user name & other details that might differ. So please read the task carefully before executing it. All the Best 👍

Solution:  

 1. At first login on app server  &  Switch to the root user 

thor@jump_host /$ ssh banner@stapp03 The authenticity of host 'stapp03 (172.16.238.12)' can't be established. ECDSA key fingerprint is SHA256:pAuLYTaL+DJ9PZla//bv+6GOgrYcoDe6al9KUjcymmA. ECDSA key fingerprint is MD5:18:ff:40:6f:6b:5b:95:cb:67:18:7a:a9:57:f6:53:92. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'stapp03,172.16.238.12' (ECDSA) to the list of known hosts. banner@stapp03's password: [banner@stapp03 ~]$ [banner@stapp03 ~]$ sudo su - We trust you have received the usual lecture from the local System Administrator. It usually boils down to these three things:     #1) Respect the privacy of others.     #2) Think before you type.     #3) With great power comes great responsibility. [sudo] password for banner: [root@stapp03 ~]#

2. Run the Below command to check existing docker images 

[root@stapp03 ~]# docker images REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE [root@stapp03 ~]#

 3. Run the Below command to  pull the docker image on the server

        

[root@stapp03 ~]# docker pull ubuntu:latest latest: Pulling from library/ubuntu a31c7b29f4ad: Pull complete Digest: sha256:b3e2e47d016c08b3396b5ebe06ab0b711c34e7f37b98c9d37abe794b71cea0a2 Status: Downloaded newer image for ubuntu:latest docker.io/library/ubuntu:latest [root@stapp03 ~]#

 4. copy file /tmp/sample.txt  to /opt dba

[root@stapp03 ~]# cp  /tmp/sample.txt  /opt/dba [root@stapp03 ~]#

5. Run docker container from the image with given name and path    

[root@stapp03 ~]# docker run --name media  -v /opt/dba:/var -d -it  ubuntu:latest 00aebc3928e31e8a21f20c599539b23504b5c02ed3ecc92b7f3bc68028012fbb [root@stapp03 ~]#

6. Validate the task by login on  docker container and list  /var  

[root@stapp03 ~]# docker ps CONTAINER ID        IMAGE               COMMAND             CREATED              STATUS              PORTS               NAMES 00aebc3928e3        ubuntu:latest       "bash"              About a minute ago   Up About a minute                       media [root@stapp03 ~]# [root@stapp03 ~]# docker exec -it 00aebc3928e3  /bin/bash root@00aebc3928e3:/# ll /var total 12 drwxr-xr-x  2 root root 4096 Jul 16 14:37 ./ drwxr-xr-x 17 root root 4096 Jul 16 14:39 ../ -rw-r--r--  1 root root   23 Jul 16 14:37 sample.txt root@00aebc3928e3:/# root@00aebc3928e3:/#

7.  Click on Finish & Confirm to complete the task successful

Happy Learning!!!!

Apart from this if you need more clarity,  I have made a  tutorial video on this , 

please go through and share your comments. Like and share the knowledge