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TASK 137: Docker Volumes Mapping

Requirements​

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 nginx image (preferably latest tag but others should work too).

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

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

Note

This page preserves the original task statement and uses one direct bind-mount workflow followed by container-side verification.

Prerequisites​

  • You can SSH to App Server 3 and switch to a privileged shell.
  • Docker is installed and the host path /opt/sysops already exists.
  • The source file /tmp/sample.txt exists on the host before you start the container.

Steps​

Login to the App Server and switch to root. For the server credentials, check out the Project Nautilus documentation.

sshpass -p  '*************' ssh -o StrictHostKeyChecking=no banner@172.16.238.12
sudo su -
*************

Check the existing docker images.

docker images

Pull the required image.

docker pull nginx:latest

Copy the sample text file to the specified directory.

cp /tmp/sample.txt /opt/sysops

Run the container using the image and specify the name and volume mapping.

docker run --name demo -v /opt/sysops:/usr/src/ -d -it nginx:latest

Check the container. Confirm that the mapping was successful.

[root@stapp03 ~]# docker ps
CONTAINER ID   IMAGE          COMMAND                  CREATED         STATUS         PORTS     NAMES
c33468e8b302   nginx:latest   "/docker-entrypoint.…"   8 seconds ago   Up 3 seconds   80/tcp    demo
[root@stapp03 ~]# docker exec -it c33468e8b302 ls -la /usr/src
total 12
drwxr-xr-x  2 root root 4096 Jun 25 14:42 .
drwxr-xr-x 14 root root 4096 Jun 12 00:00 ..
-rw-r--r--  1 root root   23 Jun 25 14:42 sample.txt

Verification​

  • Confirm the container demo is running with docker ps | grep demo.
  • Confirm the bind mount is active by checking the container contents with docker exec -it demo ls -la /usr/src.
  • Verify that sample.txt is visible inside /usr/src.

Resources​