Docker series (Part 10) : Create your own Dockerfile and create a container from it

In this blog, we are going to go through this process

We will create a file named Dockerfile and open it in terminal . We are using vim to edit it.

1.First we will import node 18-alpine
You can see the latest version of node from here : https://hub.docker.com/_/node

So, lets import the node image and tag: 18-alpine . Alpine is a very light distribution.

1. We will expose port 3000 for this app. Assume it as an instruction

2. Now, we will use alpine package manage to install
   

RUN apk add --uppdate tini

We will also create directory to copy usr/src/app using

RUN mkdir -p usr/src/app

and then go into it using

WORKDIR usr/src/app

4.Node uses a package manager and thus we will create a package.json file and copy it to the package.json file.

Then we will install dependencies using

RUN npm install

Also we will keep it small and clean thus

RUN npm cache clean

or, in short use

RUN npm install && npm cache clean

1. We will then copy everything from the current node:18-alpine using

COPY ..

1. Now we need to start the container using 'tini -- node ./bin/www'

We will use the json format to add this

CMD ["tini","--","node","./bin/www"]

Now, save this file and go to terminal. We will build the dockerfile using this command

docker build -t <random image name you wish> .

"." is given to build it in the current directory

We have got a bit problem

What happened?

Lets see the images

You may see an image with tag
As the problem occured, we faced this issue. We will solve this by making a simple change in our docker file

RUN npm install && npm cache clean --force

We will force this line to be implemented and to clear our doubts, we will now create a new image with a new name called "testimage"

This time it worked perfectly and added the latest tag.

Now, look at the images

we can see our image on top with latest tag.

So, image is created! Congratulations!

Now, lets create a container using this image

docker container run -rm -p 80:3000 --name test_container testimage

-rm is used when we want to stop the container till the moment we exit the container.

-p 80:3000 is used because it will run on 80 but listens from 3000 . Also, we exposed 3000 for that in our Dockerfile

We also have set a container name to our our container and used the image "testimage"

Now go to your web browser and type "localhost", you can see this

Go to your terminal and you will see this logs

Now press control+ C to stop it .

Now lets put this image uploaded to our Dockerhub id with a new name

docker tag testimage <dockerhub username/new image name>

Now, lets push it
using

docker push <docker hub username/image name>

Go to your dockerhub and see the image there

Congratulations! You have completed it

If you get stuck, you can see our final Dockerfile

From node:18-alpine


EXPOSE 3000

RUN apk add --update tini

RUN mkdir -p /usr/src/app

WORKDIR /usr/src/app

COPY package.json package.json

RUN npm install && npm cache clean --force
COPY . .

CMD ["tini","--","node","./bin/www"]

See you again