session11.txt

Docker:


sudo apt-get update
 
Use the following command to install packages to allow the apt to use a repository over HTTPS
sudo apt-get install \
apt-transport-https \
ca-certificates \
curl \
gnupg \
lsb-release


#Use the following curl command to add Docker’s official GPG key:

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

#Use the following command to set up a stable repository:
echo \
"deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
$(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null


#
sudo apt update
sudo apt-get install docker-ce
docker  --version


docker --version

++++++++++++++++++++++++++++++++++++++++++++++++++++++
Actual Lab:

docker run hello-world

#this going to show you All the container with running / exit state
docker ps -a

#this going to show you All the container with running state
docker ps

#Remove the exit container 
docker rm <containerid>

#list of docker image
docker images

#remove docker image
docker image rm <imageid>

++++++++++++++++++++++
#to search the marketplace images
docker search nginx


#Two way you can run a conatainer

1. Interactive terminal

2. Detach terminal

#pull nginx docker image
docker pull nginx

#run the nginx container (bydefalt it is going to run in a interactive terminal)
docker run nginx 

#run the nginx container with detach terminal (-d stands for detach -t stands for terminal)
docker run -dt nginx

#stop running container
docker stop <containername/containerid>

#start the container
docker start <containername/containerid>

#lets try to run something in a interactive, (-i stands for interactive -t stands for terminal)
docker run -it ubuntu

#we need to run to ubuntu container in a interactive terminal
#if you want to come out of the container without exit 
use shortcart ctrl+p+q

#two way you can connect to the running container with a bash process id 1
docker attach <containerid>

#Preffered process to connect running container, create new process for your terminal instead of process id 1
docker exec -it <conatainerid/name> <newprocess>
docker exec -it 8d71a634622c /bin/bash

#delete image
docker rmi <imageid/name>


#Port Mapping 

#Host Port Mapping 
1. Custom port mapping 2. Random port maping

#How to map random port
docker run -d -P nginx

#custom port
docker run -d -p7686:80 nginx


#login to the nginx container and change the default page
docker exec -it  cff034d88691 /bin/bash

#deafult page is /usr/share/nginx/html/index.html
#to change the default page I have run this command inside the interactive terminal of my nginx container
echo "Niladri Nginx for Random Port" > /usr/share/nginx/html/index.html

#Test the application default page
curl localhost:32768

#if you want to access the same nxinx server with your public ip then you need to enable the port in Network Security group which is attached with your vm


#Volume mount in you container from host filesystem
root@ip-172-31-12-78:~# mkdir dockermount
root@ip-172-31-12-78:~# pwd
/root
root@ip-172-31-12-78:~# cd dockermount/
root@ip-172-31-12-78:~/dockermount# pwd
/root/dockermount
root@ip-172-31-12-78:~/dockermount# echo "Niladri's Configuration form host file system" > index.html
root@ip-172-31-12-78:~/dockermount# cat index.html
Niladri's Configuration form host file system
root@ip-172-31-12-78:~/dockermount# echo "Niladri's Configuration form host file addition page" > niladri.html
root@ip-172-31-12-78:~/dockermount# ls
index.html  niladri.html
root@ip-172-31-12-78:~/dockermount#


#create a conatainer with the mount volume
docker run -dP -v /root/dockermount:/usr/share/nginx/html nginx

#docker logs <containerid>

#docker logs -f <containerid>

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Types of Image:
1. Base image : which start with From scratch

# syntax=docker/dockerfile:1
FROM scratch
ADD hello /
CMD ["/hello"]

2. Parent Image: which is going to refer another image

# syntax=docker/dockerfile:1
FROM node:18-alpine
WORKDIR /app
COPY . .
RUN yarn install --production
CMD ["node", "src/index.js"]
EXPOSE 3000

+++++++++++

# To create any custom image you need to maintain a Dockerfile
# You are going to define all the instruction what your image is going to do

Dockerfile Format
The Dockerfile is a raw text document. The following are some popular instructions in a Dockerfile.
FROM – This instruction defines the parent image for subsequent instructions. FROM clause must be the first entry in a Dockerfile. It can come after a comment or parse directive or ARG used in the FROM directive.

ARG – It defines variables used during the build once you run Docker build command on the file.
AD
CMD – This sets the command executed upon container creation. Docker only allows one CMD instruction per file. When you have more than one defined, it runs the last command.

LABEL – The label instruction defines metadata information for the image. You can add as many labels as you see fit in the form of key-value pairs. For example, image metadata could include the version number, author information, description, etc.

RUN – Sets the instructions to be executed during the image build.

USER – This instruction sets the username or UID of the user when running the image or instructions in a Dockerfile such as CMD, RUN, and ENTRYPOINT.
AD
ENTRYPOINT – It defines the commands Docker executes upon container creation. Options are overridable in the command line during container startup.

ADD – This instruction copies files and directories from the specified source to a specified destination. The source can be a local path or an external URL. If the files are archives, Docker automatically unpacks them into the image.

VOLUME – The volume instructions allow you to create mount points from host machine directories or other containers.

EXPOSE – This instruction tells Docker which port to listen on during runtime.

AD
ENV – It sets environment variables.

WORKDIR – sets the current working directory. If the directory specified does not exist, Docker will automatically create one.

The above are some standard instructions you can use in a Dockerfile.

#Lets create a Docker file for Custom Nginx Image:
#Dockerfile

FROM ubuntu
RUN apt-get update
RUN apt-get install -y nginx
COPY index-custom.html /var/www /html/index.html
EXPOSE 80
CMD nginx -g 'daemon off;'

+++++++++++++++
root@ip-172-31-12-78:~/customdockerimage# ls
Dockerfile  index-custom.html
root@ip-172-31-12-78:~/customdockerimage# cat Dockerfile
FROM ubuntu
RUN apt-get update
RUN apt-get install -y nginx
COPY index-custom.html /var/www/html/index.html
EXPOSE 80
CMD nginx -g 'daemon off;'
root@ip-172-31-12-78:~/customdockerimage# cat index-custom.html
This My nginx page from my Custome image
root@ip-172-31-12-78:~/customdockerimage#

++++++++++++++++++++++++
#Build the docker image
docker build -t <imagename>:<tag-version> <pathof thedockerfile>

docker build -t niladringinx:1.0 . 

#docker run
docker run -dP niladringinx:1.0