Docker

Welcome to Docker practicual example. In this repository we are going to build containers with Docker. Next we are going to make communications between our containers using Docker Network, and we are going to bind our local file system to container file system using Docker Volumes.

Nginx Container

First we are going to build a simple nginx image and customizing the html page.

FROM nginx

# creating a lable
LABEL app=nginx-example

# add maintainer
MAINTAINER amirhossein.najafizadeh21@gmail.com

# setting an argument
ARG HTML_DIR=html

# setting one env variable
ENV APP="cloud computing docker presentation"

# copy all files of html directory
COPY $HTML_DIR /usr/share/nginx/html

# run the echo command to see directory
RUN echo $HTML_DIR

# run another command
RUN export $APP

# add a command for on build
ONBUILD RUN ls /usr/share/nginx/html

# expose port 80
EXPOSE 80/tcp

As you can see, we are chaning the /usr/share/nginx/html files.

So let's build our container and start the container.

docker build . -f build/nginx/Dockerfile --build-arg HTML_DIR=/build/nginx/html -t amirhossein21/nginx:v0.1.0
docker run -p 80:80 -d amirhossein21/nginx:v0.1.0

Now make a curl to localhost:8080.

Node App

In the next example we are going to deploy a full Node.js application with Redis database on Docker.

First we need to build our network and volume:

Network

docker network create node-app

Volume

docker volume create redisvolume

Now let's start Redis cluster in node-app network, binded to redisvolume.

docker run --network=node-app -v redisvolume:/data --name node-app-redis-cluster -d redis:latest

Now that we have Redis cluster up and running, we are going to deploy our node app.

First we are going to write a Dockerfile.

FROM node:16

# Create app directory
WORKDIR /usr/src/app

# set environment variables
ENV HTTP_PORT=8080
ENV REDIS_URL=redis://node-app-redis-cluster:6379

# Install app dependencies
# A wildcard is used to ensure both package.json AND package-lock.json are copied
# where available (npm@5+)
COPY ./app/package*.json ./

# Run npm i to create node_modules directory.
RUN npm install

# If you are building your code for production
# RUN npm ci --only=production

# Bundle app source
COPY ./app .

# cmd allows us to execute the node app starting command
CMD [ "node", "index.js" ]

Pay attention to the redis cluster address:

ENV REDIS_URL=redis://node-app-redis-cluster:6379

Since our node app container and redis cluster are in one network, we can use the redis container name insted of host ip.

Build

docker build . -f build/app/Dockerfile -t amirhossein21/node-app:v0.1.0

Run

docker run --network=node-app --name node-app-container -d -p 8080:8080 amirhossein21/node-app:v0.1.0

Now make the following http requests:

curl -X POST "localhost:8080/api?key=amir&value=hossein"
curl -X GET "localhost:8080/api?key=amir"