Docker.txt

Docker
=========
When we install Docker software, below 2 components will be installed:

1)Docker Client
2)Docker Engine (Server/Host/Daemon)

Deployed 2 Java Web Applications and they are using different Java Runtime 1

Namespacing:
Isolating resources per process ( or group of processes)

Isolated area of execution of your process(es)

Resources:
Processes, Hard drive, Network, Users, Hostnames, Inter process Comunication etc.

Process Manager
Network Manager
Storage Manager
File System Manager
Finally, the application related binary and library files

Control Groups(cgroups):
Limits the amount of resources used per process

Memory, CPU usuage, Network Bandwidth etc..
=========================================

Docker is a platform or ecosystem around creating and running containers.
Docker makes it really easy to install and run software without worring about setup or dependencies.

Container is a isolated area of execution

Image: It is nothing but a mix of the application, dependencies, some libraries etc..


Install Docker:
-----------------
yum install docker -y
service docker start
service docker status

docker container --help
docker run hello-world
docker images

Create a container and in this deploy a image.
Docker hub contains many images

docker run hello-world:
run -> Pull the image form docker hub
Create the container and it will start the image inside this container.

Docker server  maintains pool of images.

docker run -it --name webserver ubuntu /bin/bash

ifconfig: To display all the available Network Ids
Port Forwarding
docker run -it --name webapp -p 3400:80 ubuntu /bin/bash
apt udpate -y
apt install apache2 -y
wget <url>
apt install wget -y
apt install unzip -y
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Dockerfile
------------
Dockerfile contains set of instructions to build docker image.

Dockerfile => We can build a image
docker run <image>
Image => Code + All the dependencies

To write Dockerfile, we use below keywords:

1)FROM
2)MAINTAINER
3)RUN
4)CMD
5)ENTRYPOINT
6)USER
7)COPY
8)ADD
9)WORKDIR
10)EXPOSE
11)ARG
12)VOLUME
etc...
--------------------------------------------
FROM keyword
-------------
FROM keyword is used to specify the base image to create our own docker image

FROM ubuntu:<version name>
FROM ubuntu
FROM python:3.6
FROM tomcat:8.0

MAINTAINER
-------------
MAINTAINER keyword is used to specify the authoer of the Dockerfile

RUN
----
RUN keyword is used to specify instructions to execute when the docker image is creating..

RUN touch file1.txt
RUN touch file2.txt

We can write multiple RUN instructions and these instructions will executed in same order

CMD Keyword
---------------
CMD keyword is used to sepecify instructions to execute when docker container is creating..

CMD "java -jar amazon-app.jar"
CMD "npm start" => React App
================================
COPY command
-------------
It is used to copy the files from host machine to container machine

COPY target/amazon-app.war /usr/app/
COPY pythonApp.py /usr/app/

===================================
ADD command 
It is used to copy the files from host machine as well as from internet to container.

ADD target/amazon-app.war /usr/app/
ADD pythonApp.py /usr/app/
ADD <url> /usr/app
--------------------------
WORKDIR keyword
-------------------
It is used to specify the working directory location to process further docker instructions

WORKDIR /usr/app

-------------------------
EXPOSE
-----------
It is used to specify on which port number our application is listening inside a container..

EXPOSE 3000
====================
ENTRYPOINT
------------
It is used to run our application code in docker container

ENTRYPOINT ["java", "-jar", "amazon-app.jar"]
============================
USER keyword
---------------
It is used to specify the USER account to execute the dockerfile instructions.

USER root
USER ram
============================
ARG keyword
------------
It is used to pass dynamic values

Ex:
ARG branch-name

RUN sh 'git clone -b $branch-name <github url>

============================
VOLUME keyword
---------------
It is used to specify DOCKER volume for storing the data

VOLUME <volume-name>
====================

Dockerfile
---------------
FROM ubuntu

RUN touch file1.txt
RUN touch file2.txt
RUN touch file3.txt
======================
Build a image using the Dockerfile
---------------------------------------
docker build -t my-custom-image .
Here -t: Tag name

##If you want to give a new dockerfile name:
EX: docker build -t react-app -f newDocFile .
-------------------
cd FedExProjectMar13/

Deploy the Shopping Website
=============================
1)Install git 
2)git clone https://github.com/madandevops2024/FedExProjectMar13.git
3)cd FedExProjectMar13/
4)Install maven => yum install maven -y
5)mvn clean package => to build the java application
6)After building the java application , copy the war file to tomcat
6)Tomcat path:
/usr/app/local/tomcat/webapps/
7)Build the image:

docker build -t shoppingsite .


8)Run the image in a container using port forwarding:
docker run -p 8080:8080 -d shoppingsite

URL: http://13.201.186.122:8080/shopping-site-web-app/
======================================================
Dockerfile:
--------------

FROM tomcat

COPY target/shopping-site-web-app.war /usr/local/tomcat/webapps/
=============================================
Dependencies:
---------------
Java Dependencies exists in a file called: pom.xml
Python Dependencies exists in: requirements 
.NET or Angular or React , their dependencies exists in: packages.json
==========================================================================
How to push Docker images to Docker Hub Account
------------------------------------------------
#login to the Docker Hub Account
$docker login => Provide your user name

#Tag docker image
<docker user name>/image name
madandevops2024/react-app

$docker tag <source name> <new name>
Ex: docker tag react-app madandevops2024/react-app

$docker push <image name>
$docker push madandevops2024/react-app
=============================================

Remove a Image
-------------------
docker rmi <image name>
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Stateful and Stateless Containers
====================================

Stateless Container: Data will be deleted after container got deleted.
Stateful Container: Date will  be maintained or saved permanently.

Even if we deploy latest code or if we recreate a container, we should not loose our data.

To maintain data permanently, we need to have a container as Stateful Container.

To make container as stateful, we need to  use Docker 'Volume' concept.
------------------------------------------------------
=>Docker volumes are used to persist the data which is generated by Docker container.

=> volume is used to avoid data loss

=> We have 3 types of volumes in Docker
a) Anonymous Volume (No name)
2) Named volume
3) Bind Mounts

----------------------------------------------------------
docker volume --help
docker volume create myvolume


How to attach the volume to a container
-----------------------------------------
docker run -it -v myvolume:/tmp ubuntu /bin/bash

$/tmp:/touch xyz{1..10}

Temporarily detach from running a container
-----------------------------------------------
control p + q

Path of the volume created:
------------------------------------------
cd /var/lib/docker/volumes/myvolume/_data

Map the myvolume to a running container:
----------------------------------------------
docker run -it -v myvolume:/tmp ubuntu /bin/bash


-----------------------------------------------------------------------
Docker Network
------------------

Micro Services:
-------------------
Service - a program
Mobile Product Service -> Java
Laptop product Service -> React

Database

-----------------------------------------
Docker Network is used to provide isolated network for containers.

By default we have 3 networks in Docker
-----------------------------------------

a)Bridge
b)Host
c)None

Docker providing network for the containers using Network Drivers
---------------------------------------------------------------------
1) Bridge (Default)
2) Host
3) None
4) Overlay (Used in Docker Swarm)
5) Macvlan

=> Bridge Driver is recommended to run standalone container. It will assign one IP for our container. This is a default driver.

=> Host Driver is also used to run standalone container. It will assign any IP for the container

=> None driver  means no network will be available for our container

=> Overlay driver is used for Orchestration (Docker Swarm)

=> Macvlan network driver will provide a physical IP for our container

Display docker networks
--------------------------
$docker network --help
$docker network ls

Create a docker network
$docker network create amzn-network 

Attach a network to our container
=====================================
docker run --network=<network name> -d ubuntu /bin/bash

docker run --network=amzn-network -d ubuntu /bin/bash

Try:
 docker run -network amzn-network -d ubuntu /bin/bash


To inspect a network
-------------------------
docker network inspect <network name>
docker network inspect amzn-network

docker network create dev-team --subnet=10.0.0.0/24
docker network create prod-team --subnet=10.0.0.0/26
=============================================================

Docker Compose
--------------------
Docker Compose is used to manage Multi-Container based applications.

To run our application which contains multiple services, then we need to create seperate container for each service.

Using Docker Compose we can easily create/run and manage multiple containers.

We use 'docker-compose.yml' file to provide the containers information to our Docker Compose tool.

This docker-compose.yml file should contain all the informatin related to containers and container dependencies as well.

The default file name is 'docker-compose.yml' but we can change it.


-----------------------------------------------------------

Docker Compose file syntax:
-------------------------------

version: Represents version number

Services: Represents our containers

network: For communication

volumes: Reprsents storage for the containers

---------------------------------
To download Docker Compose

https://docs.docker.com/compose/install/standalone/

curl -SL https://github.com/docker/compose/releases/download/v2.27.0/docker-compose-linux-x86_64 -o /usr/local/bin/docker-compose

$sudo chmod +x /usr/local/bin/docker-compose

docker-compose --version

=======================================

1)Download git repository:
https://github.com/madandevops2024/AmazonStore.git

2)Build the Java application using Build tool i.e., maven
mvn clean package

3)Buil image
docker build -t amazon-store-mysql-app .

4)Execute the docker-compose.yml
$docker-compose up -d


Connecting to a running container
=====================================
docker-compose ps
docker exec -it amazonstore-mysqldb-1 /bin/bash
bash-4>mysql -u root -proot
mysql>show databases;
mysql>use amazon-store;
mysql>show tables;
mysql>select * from product;
mysql>exit
bash-4>exit

To terminate the containers
5)docker-compose down

To stop running container
6)docker-compose stop

To start running container
7)docker-compose start


#Docker Containers can be made as Stateful uisng Bind Mount Volume

8)$mkdir data
--------------------------------------------------------

Docker Swarm
===============
#It is a container orchestration platform.

#Orchestration means managing multiple containers

#Docker Swarm is used to setup Docker Cluster

#Cluster means group of servers

#We will setup Master and Worker nodes using Docker Swarm 

#Master node will schedule the tasks (creating the containers) and manage the nodes (EC2 instances/virtual machines/servers) and node failure

#Worker nodes will perform the actions based on master node instructions.

#Docker Swarm is already available in Docker Engine

Docker Swarm Features
-------------------------
1)Cluster Management
2)Scaling
3)Load Balancing
etc..

Docker Swarm Cluster Setup
---------------------------
1)Create 3 EC2 instance (Amazon linux) and install Docker in all the 3 instances.

2)Add Port 2377 in Security Group (assuming all 3 instances having common SG) so that Docker Swarm can communicate with the worker nodes (in the cluster)

3) Add required port number as per the application that we deployed in the Security Group. 

1) Master Node
2) Worker Node

---------------------

#Run below command to initialize and create the master node:
$docker swarm init --advertise-addr <private IP address>
$docker swarm init --advertise-addr 172.31.12.4

#Copy the token and execute in all the worker nodes so that they can join with the master node

Ex:
docker swarm join --token SWMTKN-1-2rr90kny9izjpm51gtcu8c7k9313zz0duh716euyl9z2z9no6c-c802n7i2if28baouweizaw6oy 172.31.12.4:2377

Docker Swarm Service
-----------------------
#Service is a collection of one or more containers of SAME image

#There are 2 types of services in Docker Swarm
a)Replica (Default Mode)
b)global

$docker service create --name <name of the service> -p <host port>:<container port> <image Name>

Run only on the Master Node:
------------------------------
$docker service create --name shoppingsite-service -p 8080:8080 madandevops2024/shoppingsite 

#Check whether service is available or not
$docker service ls

#We can access our application using below URL:
http:/<master node public ip>:8080

#Verify service details
$docker service ps <service name>
$docker service ps shoppingsite-service

#We can scale multiple containers using docker service
$docker service scale <service name>=<number of replicas>
$docker service scale shoppingsite-service=2

#Remove docker service
$docker service rm shoppingsite-service

#Remove one node or more from the swarm cluster
$docker swarm leave
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