• Check the Docker Version

        docker version

• note : if client and server are show then successfully done

• make a docker file for dockerize the image with container

        echo > Dockerfile

• note : no need to take any extension of this file

• Add Base Image like node python etc

                node:version

• the size of container is too big because it apply default linux flavour
• so we metion the flavour

• • alpine flavour provide consumable size to dockerize the image -[min 300mb].

        node:18-alpine3.12

Copy the items in the container

        COPY source destination

• example ->

•      COPY index.js /app/
  

• note if the /app/ directory is not present then it create also

to copy all all in the current folder then we use (.)

• you also say the destination as a working directory

example ->

     COPY . /app/

• in the node js we have node_modules so we dont need to push the node_modules folder so we ignore the file

        .dockerignore

• in this file we write name of files we dont need to push in image

example

node_modules/

To navigate to working DIR

            WORKDIR /folder

• we also define working directory at the top

                node:18.16.1-alipne:3.12
                WORKDIR /app/
                COPY . .

• example check image avilabel

• in the copy . .

{
        - Copy is used to copy the data in the container image 
        - first . is represent the currenty dir source 
        -  {except dockerignore file data }
        - second . is represent WORKDIR destination
}```

# install node modules after copy in the destination
 
```bash
  RUN npm install

• after push the code it install the dependecies which are write in package.json

run multiple command .

   RUN apk add --no-cache npm \&& npm install \&& npm install -D nodemon

to start the development/production server after install the node_modules in image with the use of CMD and ENTRYPOINT

• with CMD

        cmd ['npm','run','dev'] #for development
        cmd ['npm','run','start'] # for production

• with ENTRYPOINT

        ENTRYPOINT ['npm','run','dev'] #for development
        ENTRYPOINT ['npm','run','start'] # for production

• the second way to write command

        cmd npm run dev         

• it create a new session , so that by it not recommanded

Difference Between run and cmd command

• in the image there are many command to build the docker image but the cmd command only one and at the last on the dockerfile

• RUN : It runs during build time, while creating an image or running any other Docker commands like exec etc., but its output will be discarded as there won’ t exist anything on console or logs when you use this instruction inside Dockerfile.
• CMD : it run to start the server once your application has been built successfully using CMD directive of Dockerfile. This means whenever our containers get started.

build the image after creating the file

• go the root folder path
• open the ternimal of vs code/cmd

                docker build -t <image-name> <desitination of docker file >

• -t stand for tag image tag
• example docker build -t myapp .
• . because it in current file

• Check the docker image with desktop

To check docker images with command line

      docker images  # simple command
      docker image ls # for listing

create a docker container

• the container is used to run the docker image

• it first load the image in conatainer and then it runs

                docker container run < app_name >