Accessing & Managing Docker Image

• Accessing the Container Shell
• Running a Command inside running Container
• Managing Docker Containers
• Test Your Knowledge

Accessing the Container Shell

Tested Infrastructure

Platform	Number of Instance	Reading Time
Play with Docker	1	5 min

Pre-requisite

• Create an account with DockerHub
• Open PWD Platform on your browser
• Click on Add New Instance on the left side of the screen to bring up Alpine OS instance on the right side

Create Ubuntu Container

docker run -dit ubuntu 

Accessing the container shell

docker exec -t <container-id> bash

Accesssing the container shell

docker attach <container-id>

Running a command inside running Container

Tested Infrastructure

Platform	Number of Instance	Reading Time
Play with Docker	1	5 min

Pre-requisite

• Create an account with DockerHub
• Open PWD Platform on your browser
• Click on Add New Instance on the left side of the screen to bring up Alpine OS instance on the right side

Create Ubuntu Container

docker run -dit ubuntu

Opening up the bash shell

docker exec -t <container-id> bash

Managing Docker containers

Tested Infrastructure

Platform	Number of Instance	Reading Time
Play with Docker	1	5 min

Pre-requisite

• Create an account with DockerHub
• Open PWD Platform on your browser
• Click on Add New Instance on the left side of the screen to bring up Alpine OS instance on the right side

Preparations

• Clean your docker host using the commands (in bash):

$ docker rm -f $(docker ps -a -q)

Instructions

• Run the following containers from the dockerhub:

$ docker run -d -p 5000:5000 --name app1 selaworkshops/python-app:1.0

$ docker run -d -p 5001:5001 -e "port=5001" --name app2 selaworkshops/python-app:2.0

• Ensure the containers are running:

$ docker ps

• Stop the first container:

$ docker stop app1

• Kill the second container:

$ docker kill app2

• Display running containers:

$ docker ps

• Show all the containers (includind non running containers):

$ docker ps -a

• Let’s start both containers again:

$ docker start app1 app2

• Restart the second container:

$ docker restart app2

• Display the docker host information with:

$ docker info

• Show the running processes in the first container using:

$ docker top app1

• Retrieve the history of the second container:

$ docker history selaworkshops/python-app:2.0

• Inspect the second container image:

$ docker inspect selaworkshops/python-app:2.0

• Inspect the first container and look for the internal ip:

$ docker inspect app1

"Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "822cb66790c6358d9decab874916120f3bdeff7193a4375c94ca54d50832303d",
                    "EndpointID": "9aa96dc29be08eddc6d8f429ebecd2285c064fda288681a3611812413cbdfc1f",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.3",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:03",
                    "DriverOpts": null
                }
            }

• Show the logs of the second container using the flag –follow:

$ docker logs --follow app2

• Browse to the application and see the containers logs from the terminal:

http://localhost:5001

• Stop to tracking logs:

$ CTRL + C

Test Your Knowledge - Quiz2

S. No.	Question.	Response
1	What are different ways to access container shell?
2	How to run a command inside a Docker container
3	Is it possible to stop overall Docker containers in a single shot?
4	How do you remove all dangling images in Docker?
5	How do you access services ports under Docker?