Explanation:

To uninstall docker

sudo apt-get purge docker-ce
sudo rm -rf /var/lib/docker
Note: The output of the below command will provide you with information the installed package software, version, architecture and short description about the package. grep command is used to find the docker package
sudo dpkg --get-selections | grep docker | cut -f 1
sudo apt-get remove --purge <package name from the previous command output>
sudo whereis docker
sudo rm -rf <directory/file path from the previous command output>

Explanation:

 * Containers and virtual machines both have similar resource allocation and allocation benefits.
 * Containers and VMs are functionally different because containers virtualise the Operating System and VMs are virtualise the hardware.
 * Containers are just processes

Explanation:

ubuntu@ip-172-31-59-138:/opt/HelloWorld$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
xdk_helloworld latest a801afaa1782 20 seconds ago 473MB
tomcat jre8 3639174793ba 3 months ago 463MB

Command to run the xdk_helloworld docker image, to listen to the port 80 and route to 8080 in the container which is the tomcat's default port 8080 at runtime.

ubuntu@ip-172-31-59-138:/opt/HelloWorld$ docker run -p 80:8080 xdk_helloworld

Open http://34.204.171.134/HelloWorld/ in a browser to see the HelloWorld web is application running.

Explanation:

1. How to install Docker on Ubuntu 18.04?
2. Docker Command
3. Working with Docker Images
4. What is a dockerfile?
5. How to build a custom docker image?
6. How to run a container?
7. How to SSH into a running container?
8. How to push an image to Docker Hub?
9. How to pull an image from Docker Hub?

Explanation:

Command to get the name of the existing container

ubuntu@ip-172-31-57-91:/opt/HelloWorld$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2a41bd524e93 xdkdockerhub/xdkdockerrepo:xdk_helloworld_V1 "catalina.sh run" 5 minutes ago Up 5 minutes 0.0.0.0:80->8080/tcp sweet_hypatia

Command to get a bash shell in the container.
ubuntu@ip-172-31-57-91:/opt/HelloWorld$ docker exec -it sweet_hypatia bash

Verify with basic commands

root@2a41bd524e93:/usr/local/tomcat# ls -a

. BUILDING.txt LICENSE README.md RUNNING.txt conf lib native-jni-lib webapps
.. CONTRIBUTING.md NOTICE RELEASE-NOTES bin include logs temp work

root@2a41bd524e93:/usr/local/tomcat# ls -al
total 168
drwxr-sr-x 1 root staff 4096 May 16 00:50 .
drwxrwsr-x 1 root staff 4096 May 8 13:20 ..
-rw-r--r-- 1 root root 19539 May 4 09:22 BUILDING.txt
-rw-r--r-- 1 root root 5407 May 4 09:22 CONTRIBUTING.md
-rw-r--r-- 1 root root 57092 May 4 09:22 LICENSE
-rw-r--r-- 1 root root 1726 May 4 09:22 NOTICE
-rw-r--r-- 1 root root 3255 May 4 09:22 README.md
-rw-r--r-- 1 root root 7139 May 4 09:22 RELEASE-NOTES
-rw-r--r-- 1 root root 16262 May 4 09:22 RUNNING.txt
drwxr-xr-x 2 root root 4096 May 16 00:50 bin
drwxr-sr-x 1 root root 4096 Aug 25 11:56 conf
drwxr-sr-x 2 root staff 4096 May 16 00:50 include
drwxr-xr-x 2 root root 4096 May 16 00:49 lib
drwxrwxrwx 1 root root 4096 Aug 25 11:56 logs
drwxr-sr-x 3 root staff 4096 May 16 00:50 native-jni-lib
drwxr-xr-x 2 root root 4096 May 16 00:49 temp
drwxr-xr-x 1 root root 4096 Aug 25 11:56 webapps
drwxrwxrwx 1 root root 4096 Aug 25 11:56 work
root@2a41bd524e93:/usr/local/tomcat# exit
exit
ubuntu@ip-172-31-57-91:/opt/HelloWorld$