DevOps Classroomnotes 07/Jan/2022

Install Docker on Linux

• We need an linux instance. We will be create a linux instance in
• AWS Cloud Refer Here
• Azure Refer Here
• Ubuntu:

curl -fsSL https://get.docker.com -o get-docker.sh
sh get-docker.sh
sudo usermod -aG docker <username> #$USER
exit
# relogin

* Centos:

curl -fsSL https://get.docker.com -o get-docker.sh
sh get-docker.sh
sudo usermod -aG docker <username> #$USER
exit
# relogin
sudo systemctl enable docker.service
sudo systemctl start docker.service
docker info

• The script which we have used to install docker always installs the latest stable version of docker.
• Refer Here for the shell script used

Docker Image and Container Creation Basics

• Lets see the list of the images in the newly installed docker

docker image ls

• Downloading the image from registry is called as pull
• The image name has two components <name-of-image>:<tag>
• name of the image represents application
• tag represents the version
• If you dont pass the tag, docker will consider tag as latest so
• if you have written image name as httpd == httpd:latest
• Now lets pull the jenkins/jenkins image

docker image pull jenkins/jenkins

* Now lets look at the tags of jenkins/jenkins Refer Here

* Every image in the registry will have unique image id.
* Two different images have the same image id imply that they are same images with different names.

* Lets create a jenkins container docker container run -d <image>:<tag>

docker container run -d jenkins/jenkins
docker container ls

* To access the application inside the docker we have to do port forwarding docker container run -d -p <hostport>:<containerport> <imageid>:<tag>


* Lets try to create an apache continer


* Overview of portforwarding

* Docker can map the container port to dynamic port on the Docker Host (Linux VM) docker container run -d -P <imageid>:<tag>