Docker EXEC Operations.md

Problem Statement

A Nautilus DevOps team member was configuring services on a kkloud container running on App Server 2 in the Stratos Datacenter. This team member is currently on PTO for the rest of the week, and the remaining configuration tasks need to be completed as soon as possible. The tasks are as follows:

• Install Apache2 in the kkloud container using apt.
• Configure Apache to listen on port 3000 instead of the default HTTP port. Ensure Apache listens on all network interfaces (localhost, 127.0.0.1, container IP, etc.), not just a specific IP or hostname.
• Ensure the Apache service is running and the container remains in a running state at the end.

Solution

1. Identify the Container

   Start by listing all running containers to locate the kkloud container and obtain its container ID.

   docker container ls

   Example output:

   CONTAINER ID   IMAGE          COMMAND       CREATED          STATUS          PORTS     NAMES
   19dc0db308b7   ubuntu:18.04   "/bin/bash"   14 minutes ago   Up 14 minutes             kkloud
   

   Here, 19dc0db308b7 is the container ID of the kkloud container.

2. Access the Container

   Use the docker container exec command to open a bash shell inside the kkloud container.

   docker container exec -it 19dc0db308b7 /bin/bash

3. Install Apache2

   Inside the container, install Apache2 using the apt package manager.

   apt update
   apt install -y apache2

   The -y flag automatically confirms the installation prompts.

4. Configure Apache to Listen on Port 3000

   Modify Apache’s configuration to change the listening port from the default port 80 to port 3000. Edit the necessary configuration files:

   • Open the ports.conf file:

     vi /etc/apache2/ports.conf

     Update it to:

     Listen 3000

   • Open the default site configuration file:

     vi /etc/apache2/sites-enabled/000-default.conf

     Ensure the file contains:

     <VirtualHost *:3000>
         # Other directives here
     </VirtualHost>

     Remove or comment out any lines specifying port 80.

5. Restart Apache Service

   After making the changes, restart the Apache2 service to apply the new configuration.

   service apache2 restart

   Ensure Apache restarts without issues and begins listening on port 3000.

6. Verify Apache Status

   To confirm that Apache is running and listening on the new port, you can use the following command inside the container:

   netstat -tuln | grep 3000

   This will show if Apache is listening on port 3000.