Mohamed-abdalazez / Docker

Follow-up Docker Practical Course From Tresmerge YouTube Channel

Docker Practical Course - Tresmerge

Table of content

1. Docker desktop.

2. Basic Dockerfile.

3. Basic Command Lines.

4. The difference between images and containers.

5. Docker Optimization.

6. Volumes.

7. Hot Reload.

8. Docker Compose.

9. Environment Variables.

10. Docker Environments Management.

11. Multi-Stage Dockerfile.

12. Docker with different services.

    • MongoDB.
    • NodeJS.
    • Mongo-Express.
    • Redis.
    • Nginx.
    • PostgreSQL.

13. Docker with Laravel.

14. Setup Docker on AWS EC2 and deploy the node application to the server.

15. Push Images to DockerHub.

16. Load Balancing with Nginx.

17. Automate Docker Deployment.

18. How CI/CD Works.

19. Docker Orchestration.

20. Docker Swarm.

21. Rolling Update.

Docker desktop

• First of all, you have to install Docker desktop on your machine.

Basic Dockerfile

FROM node:14

WORKDIR /app

COPY package.json .

RUN npm install 

COPY . .

EXPOSE 4000

CMD [ "npm", "start" ]

1. FROM node:14

Inside the container, install node js.

2. WORKDIR /app

Create Folder "app".

3. COPY package.json .

copy package.json inside "app" Folder.

4. RUN npm install

RUN nmp install to install all the packages inside package.json -> node_modules.

5. COPY . .

Copy all files inside the container.

6. EXPOSE 4000

The app will run on port 4000, just for documentation.

7. CMD [ "npm", "start" ]

Run the App using npm.

8. CMD [ "npm", "run", "start-dev" ]

Run the App using nodemon, To make the server detect all the changes.

• Check out the figure for more explanation.

Basic Command Lines

1. docker build -t "name of the Dockerfile"

• example:- docker build -t express-node-app .
• After build the Dockerfile (you have an "image" now).
• Dockerfile → bulid → image → Run → Container.

2. docker run --name "name of the container" "name of image"

• example:- docker run --name express-node-app-container express-node-app, 1st way.
• example:- docker run --name express-node-app-container -d express-node-app, 2nd way, What is new here is the flag -d for detach the logs.

3. docker run --name "name of the container" "name of image"

• example:- docker run --name express-node-app-container express-node-app, 1st way.
• example:- docker run --name express-node-app-container -d express-node-app, 2nd way, What is new here is the flag -d for detach the logs.
• Now, if you run the app on your localhost, it doesn't work. You have to forward the port first. How?! , See the following command line.

4. docker run --name "name of the container" -d -p my local machine port:container port "name of image"

• example:- docker run --name express-node-app-container -d -p 4000:4000 express-node-app

5. docker image ls

• list all images.

6. docker image ls

• list all the running containers.

7. docker rm "the name of container" -f

• example:- docker rm express-node-app-container -f.

8. docker exec -it "name of the container" bash

• example:- docker exec -it express-node-app-container bash.
• Open an interactive terminal in the container.
• Your terminal now:

root@dee98138027a:/app# ls
Dockerfile  index.js  node_modules  package-lock.json  package.json
root@dee98138027a:/app#

9. docker logs "the name of container"

• example:- docker logs express-node-app-container.
• To see the logs of the container.

10. docker --help

• For all command-line details.

The difference between images and containers

• Check out the figure.

Docker Optimization

• Create .dockerignore to avoid useless files.
• Why was the package.json file copied first and then all the other files copied again?
• Good question; check the figure for the answer.

Volumes

• When do we need Docker Volumes?
• What exactly is Docker Volumes?
• Docker Volumes Types.
• Check out the figure.

Hot Reload

• syncing between the local environment and the container.
• When you run the container, use that run --name "name of the container" -v absolute path for your local directory:Whatever directory is inside the container you want to sync with -d -p my local machine port:container port "name of image".
• example:- docker run --name express-node-app-container -v /home/mohamed/Desktop/Safrot/Projects/Docker/node-app:/app -d -p 4000:4000 express-node-app.
• Also, you can use this instead of the full path:
  • Linux and mac: $(pwd), The command line will be as follows: docker run --name express-node-app-container -v $(pwd):/app -d -p 4000:4000 express-node-app.
  • Windows: %cd%, The command line will be as follows: docker run --name express-node-app-container -v %cd%:/app -d -p 4000:4000 express-node-app.
• But what are the problems here?
  • If you add or delete files inside the container or on the local machine, this will change both sides at the same time.
  • One suggested solution is to sync or bind the application source code on your localhost with the application source code in the container, considering that you make the directory in the container read-only.
  • example:
    • docker run --name express-node-app-container -v $(pwd)/src:/app/src:ro -d -p 4000:4000 express-node-app

Docker Compose

• What is Docker Compose?

  • Docker Compose is a tool for defining and running multi-container Docker applications.by using a YAML file to configure your application services. Then, with a single command, you create and start all the services in your configuration.

• docker-compose.yml:

version: "3"
services:
 node-app: 
   container_name: express-node-app-container
   build: .
   volumes:
     - ./src:/app/src:ro
   ports: 
     - "4000:4000"

• Check out the figure.

Environment Variables.

• How to pass environment variables to the container?

  1. Via the Dockerfile itself, as follows:
     • You'll notice here that we used ENV PORT=4000 inside the Docker file itself.

  FROM node:14
  
  WORKDIR /app
  
  COPY package.json .
  
  RUN npm install 
  
  COPY . .
  
  ENV PORT=4000
  
  EXPOSE $PORT
  
  CMD [ "npm", "run", "start-dev" ]
  
  

  2. Via the command line, as follows:

  --env list                       Set environment variables
  --env-file list                  Read in a file of environment variables
  

  • eg:

  - Set environment variables:
  docker run --name express-node-app-container -v $(pwd)/src:/app/src:ro --env PORT=400 --env NODE_ENV=development -d -p 4000:4000 express-node-app
  - Read in a file of environment variables:
  docker run --name express-node-app-container -v $(pwd)/src:/app/src:ro --env-file ./.env -d -p 4000:4000 express-node-app
  

  • So, if you open an interactive terminal in the container and use printenv, you will find your env variables.

  $ docker exec -it express-node-app-container bash
  root@78ca00db2d62:/app# printenv
  PORT=400
  NODE_ENV=development
  

  3. Via the docker-compose, as follows:
  • Set environment variables.

  version: "3"
  services:
      node-app: 
       container_name: express-node-app-container
       build: .
       volumes:
        - ./src:/app/src:ro
       ports: 
        - "4000:4000"
       environment:
        - Port=4000
        - NODE_ENV=production

  • Read in a file of environment variables.

   version: "3"
   services:
       node-app: 
        container_name: express-node-app-container
        build: .
        volumes:
         - ./src:/app/src:ro
        ports: 
         - "4000:4000"
        env_file:
         - ./.env

Docker Environments Management

• Docker environment management across multiple environments.
• Check out the figure.

• the command lines in the figure, to be copied if you want
  • Run: docker-compose -f docker-compose.dev.yml up -d
  • Run: docker-compose -f docker-compose.prod.yml up -d
  • Development Run: docker-compose -f docker-compose.yml -f docker-compose.dev.yml up -d
  • Production Run: docker-compose -f docker-compose.yml -f docker-compose.prod.yml up -d
  • docker exec -it express-node-app-container bash

Multi-Stage Dockerfile

• The first solution is that you can create a Dockerfile for each environment.

• The second solution is that you can create a single Docker file and manage all environments through it.

• Let's delve deeper into the second solution.

  • We have to run CMD [ "npm", "start" ] in production and CMD [ "npm", "run", "start-dev" ] in development.
  
  
  • development:

   version: "3"
   services:
    node-app:
     volumes:
       - ./src:/app/src:ro
     environment:
       - NODE_ENV=development
     command: npm run start-dev

  • production:

   version: "3"
   services:
    node-app:
     environment:
       - NODE_ENV=production
     command: npm run start

  • Nodemon is installed in node modules, although we are running the container from the production compose file and not from the development compose file. There are two solutions to this problem.

    1. Make a simple check to verify the environment.
       

       
       

       • the command lines in the figure, to be copied if you want.
         
         • simple check
           

         RUN if ["$NODE_ENV" = 'production'];\
         then nmp install --only=production;\
         else npm install;\
         fi
         

         • docker-compose -f docker-compose.yml -f docker-compose.dev.yml up -d --build

         • docker-compose -f docker-compose.yml -f docker-compose.prod.yml up -d --build

    2. The Multi-Stage environment.
       

    • The Multi-Stage environment is when you separate the Dockerfile for more than one stage.

    • Check out the figure.

      
      

    • the command lines in the figure, to be copied if you want.
      

      • Docker File with multistage
        

        FROM node:14 as base
        
        FROM base as development
        
        WORKDIR /app
        COPY package.json .
        RUN npm install 
        COPY . .
        EXPOSE 4000
        CMD [ "npm", "run", "start-dev" ]
        
        FROM base as production
        
        WORKDIR /app
        COPY package.json .
        RUN npm install --only=production 
        COPY . .
        EXPOSE 4000
        CMD [ "npm", "start"]
        

        • docker-compose -f docker-compose.yml -f docker-compose.dev.yml up -d --build

        • docker-compose -f docker-compose.yml -f docker-compose.prod.yml up -d --build

Docker with different services

• You can find the code in the Services folder.

• MongoDB & NodeJS & Mongo-Express.

• Check out the figure.

  
  
  
  
  
  
  
  
  

• Some command lines you have to know here are:

  • docker inspect "name of the container", Return low-level information on Docker objects.

  • docker volume ls, List volumes.

  • docker volume prune, Remove all unused local volumes.

  • And always remember that if you use --help after any utility, you will get more information about all command lines.

    • eg. docker volume --help
    
    

    Usage:  docker volume COMMAND
    
    Manage volumes
    
    Commands:
    create      Create a volume
    inspect     Display detailed information on one or more volumes
    ls          List volumes
    prune       Remove all unused local volumes
    rm          Remove one or more volumes
    
    Run 'docker volume COMMAND --help' for more information on a command.
    
    

• Redis.

  • As we have learned, go to the Docker Hub and search for Redis; you will find the official version. You can find how to add the service in the documentation.
  • Now add the new container to docker-compose.yml.As we did in the last part.
  
  
  

  • Now let's run the app, docker-compose -f docker-compose.yml -f docker-compose.dev.yml up -d, You can see:

    Status: Downloaded newer image for redis:latest
    Creating services_mongo-express_1   ... done
    Creating express-node-app-container ... done
    Creating services_mongo_1           ... done
    Creating services_redis_1           ... done 
    

  • Important thing to remember, When you start running containers, it will start randomly, so if one container depends on another, you have to specify this.As follows:

  
  
  
  

• Nginx

  • As we have learned, go to the Docker Hub and search for Nginx; you will find the official version. You can find how to add the service in the documentation.
  • Now add the new container to docker-compose.yml.As we are used to.
  
  
  

  • Now let's run the app, docker-compose -f docker-compose.yml -f docker-compose.dev.yml up -d, You can see:

     Status: Downloaded newer image for nginx:stable-alpine
     Creating services_redis_1 ... done
     Creating services_mongo_1 ... done
     Creating services_nginx_1 ... done
     Creating express-node-app-container ... done
     Creating services_mongo-express_1   ... done
    

  • Now let's make the nginx server receive the requests and forward them to my node-app.

    
    
    

• PostgreSQL

  • As we did in Mongo previously, go to the Docker Hub and search for PostgreSQL; you will find the official version. You can find how to add the service in the documentation.

  • I'll just include docker-compose and how to connect to Postgresql here. and the explanation as above.

  • Add the Container:
    

  version: "3"
  services:
    node-app: 
      container_name: express-node-app-container
      ports: 
        - "4000:4000"
      env_file:
        - ./.env
      depends_on:
        - postgres
    postgres:
      image: postgres
      restart: always
      volumes:
       - postgres-db:/var/lib/postgresql/data #Named volume
      environment:
        POSTGRES_USER: root  
        POSTGRES_PASSWORD: example
  volumes:
    mongo-db: 
    postgres-db:

  • Connect to PostgreSQL:

        const express = require("express");
        const { Client } = require("pg");
    
       // init app
       const PORT = process.env.PORT || 4000;
       const app = express();
    
       // connect PostgresSQL
       const POSTGRES_USER = "root";
       const POSTGRES_PASSWORD = "example";
       const DB_PORT = 5432;
       const DB_HOST = "postgres";
    
       const URI = `postgresql://${POSTGRES_PASSWORD}:${POSTGRES_USER}@${DB_HOST}:${DB_PORT}`;
    
       const client = new Client({
       connectionString: URI,
       });
    
       client
       .connect()
       .then(() => console.log("connected to PostgresSQL db..."))
       .catch((err) => console.log("failed to connect to PostgresSQL db: ", err));
    
       app.get("/", (req, res) => {
       res.send("<h1>Hi guess who i am :D</h1>");
       });
    
       app.listen(PORT, () => console.log(`Hi Hi! from ${PORT}`));

• Sure, you can search for more details about the usage of each service. Here, it just explains how to communicate between Docker and different services.

Docker with Laravel

• Laravel provides Sail, a built-in solution for running your Laravel project using Docker.
• You can choose your sail services.
  • Go to the Installation and choose the suitable operating system.
  • curl -s https://laravel.build/example-app?with=mysql,redis | bash, for Linux.
  • After installation is done: Dive in with: cd example-app && ./vendor/bin/sail up
  • You can find the code in the Laravel Sail folder.

Setup Docker on AWS EC2 and deploy the node application to the server.

• Simply:

  • Set up an Ubuntu server using the Amazon Elastic Compute Cloud service.

  • Install Docker on our server.

  • Clone the node app from github.

  • run and build docker-compose file.

  • Check the figure for more details.

    
    
    
    
    
    
    

Push Images to DockerHub

• In the last part, we found that we were building and running the image on the server, which is a waste of server resources, so we want to build the image somewhere other than the server.

• So the good scenario is that the image should first be pulled from somewhere, and then it should be run on the server.

  • We can do that using:
    • Amazon Elastic Container Registry (Amazon ECR).
    • Docker hub.

• Check the figure for more details.

  
  
  
  
  
  
  

Load Balancing with Nginx.

• Check the figure for more details.

  
  
  
  
  
  
  
  
  

Automate Docker Deployment

• When using Watchtower, Once you have pushed your image to Docker Hub, the server can pull the changes automatically.

• Watchtower is itself packaged as a Docker container, so installation is just pulling the containrrr/watchtower image.

• Run Watchtower Continer.

ubuntu@ip-172-31-51-54:~/naruto-server$ docker run -d --name watchtower -e WATCHTOWER_TRACE=true -e WATCHTOWER_POLL_INTERVAL=30 -v /var/run/docker.sock:/var/run/docker.sock containrrr/watchtower express-node-app-container
Unable to find image 'containrrr/watchtower:latest' locally
latest: Pulling from containrrr/watchtower
7e1f4ce8770d: Pull complete 
cc408d374d64: Pull complete 
4412f0a27731: Pull complete 
Digest: sha256:0ca7a88fd0748aa6f32e50b67eb11148cdb989fc595264c2778c85297a2c1abe
Status: Downloaded newer image for containrrr/watchtower:latest
1a4c331c4d04caf8831d3ed12068ddad0e29cbb263d8da8716cdfa26be9e305a
ubuntu@ip-172-31-51-54:~/naruto-server$ sudo docker ps
CONTAINER ID   IMAGE                   COMMAND                  CREATED          STATUS          PORTS      NAMES
1a4c331c4d04   containrrr/watchtower   "/watchtower express…"   21 seconds ago   Up 19 seconds   8080/tcp   watchtower
ubuntu@ip-172-31-51-54:~/naruto-server$ 

• Now, once you have pushed the new image to Docker Hub, the server can pull the changes automatically.

ubuntu@ip-172-31-51-54:~/naruto-server$ sudo docker logs watchtower
time="2023-02-07T06:30:52Z" level=debug msg="Sleeping for a second to ensure the docker api client has been properly initialized."
time="2023-02-07T06:30:53Z" level=debug msg="Making sure everything is sane before starting"
time="2023-02-07T06:30:53Z" level=debug msg="Retrieving running containers"
time="2023-02-07T06:30:53Z" level=debug msg="There are no additional watchtower containers"
time="2023-02-07T06:30:53Z" level=debug msg="Watchtower HTTP API skipped."
time="2023-02-07T06:30:53Z" level=info msg="Watchtower 1.5.3"
time="2023-02-07T06:30:53Z" level=info msg="Using no notifications"
time="2023-02-07T06:30:53Z" level=info msg="Only checking containers which name matches \"express-node-app-container\""
time="2023-02-07T06:30:53Z" level=info msg="Scheduling first run: 2023-02-07 06:31:23 +0000 UTC"
time="2023-02-07T06:30:53Z" level=info msg="Note that the first check will be performed in 29 seconds"
time="2023-02-07T06:30:53Z" level=warning msg="Trace level enabled: log will include sensitive information as credentials and tokens"
time="2023-02-07T06:31:23Z" level=debug msg="Checking containers for updated images"
time="2023-02-07T06:31:23Z" level=debug msg="Retrieving running containers"
time="2023-02-07T06:31:23Z" level=info msg="Session done" Failed=0 Scanned=0 Updated=0 notify=no
time="2023-02-07T06:31:23Z" level=debug msg="Scheduled next run: 2023-02-07 06:31:53 +0000 UTC"
time="2023-02-07T06:31:53Z" level=debug msg="Checking containers for updated images"
time="2023-02-07T06:31:53Z" level=debug msg="Retrieving running containers"
time="2023-02-07T06:31:53Z" level=info msg="Session done" Failed=0 Scanned=0 Updated=0 notify=no
time="2023-02-07T06:31:53Z" level=debug msg="Scheduled next run: 2023-02-07 06:32:23 +0000 UTC"
time="2023-02-07T06:32:23Z" level=debug msg="Checking containers for updated images"
time="2023-02-07T06:32:23Z" level=debug msg="Retrieving running containers"
time="2023-02-07T06:32:23Z" level=info msg="Session done" Failed=0 Scanned=0 Updated=0 notify=no
time="2023-02-07T06:32:23Z" level=debug msg="Scheduled next run: 2023-02-07 06:32:53 +0000 UTC"

• The image is automatically pulled in this case.

time="2023-02-07T07:21:10Z" level=debug msg="Pulling image" container=/express-node-app-container image="mo201/node-app-docker:latest"

How CI/CD Works

• CI/CD: Continuous integration (CI) and continuous delivery or deployment (CD)
• CI/CD is a process that ensures that you will not have problems when adding new features to your application.
  • In the CI stage, the feature is tested; are all test cases correct, or should it be reconsidered?
  • If everything is ok, the feature will be merged with the main branch, and it will be ready to go to the next stage, which is called CD.
  • That's it in brief.

Docker Orchestration

• Docker Orchestration, its management layer, gives you more features than Docker.
  • It makes the deployment process easier by being responsible for creating and running the servers. You only have to specify the cloud provider and the docker compose file.
  • Responsible for scaling up or down the application if required.
  • Create a load balancer and manage the traffic automatically.
  • The communication between the containers and any external resource is managed automatically.
  • Detect any error in any container on the server and deal with it.
  • The update policy is specified.
  • So we note that the Docker orchestration will manage all of this.
    • deployment.
    • scaling.
    • networking.
    • errors.
    • updates.
  • Examples of Docker orchestration technologies.
    • Docker Swarm.
    • Kubernetes.

Docker Swarm

• Check out the figure.

• Note that Docker Swarm comes with Docker by default, but by default it is inactive, so you have to activate it as follows:

ubuntu@ip-172-31-51-54:~$ docker swarm init
Swarm initialized: current node (swum4h7tying0puihmos666a7) is now a manager.

To add a worker to this swarm, run the following command:

    docker swarm join --token SWMTKN-1-0g8yk6n7gz2i5duoobeobx7gupphd9t7xdw4780g6zgvi0ccfm-bl2b9w9smx5z51bv33rgr0403 172.31.51.54:2377

To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.

• Other command lines in Docker Swarm and their uses:

ubuntu@ip-172-31-51-54:~$ docker swarm --help

Usage:  docker swarm COMMAND

Manage Swarm

Commands:
  ca          Display and rotate the root CA
  init        Initialize a swarm
  join        Join a swarm as a node and/or manager
  join-token  Manage join tokens
  leave       Leave the swarm
  unlock      Unlock swarm
  unlock-key  Manage the unlock key
  update      Update the swarm

Run 'docker swarm COMMAND --help' for more information on a command.

• To begin using Docker Swarm on the server, the commands begin with docker service; let's list all of them.

ubuntu@ip-172-31-51-54:~$ docker service --help

Usage:  docker service COMMAND

Manage Swarm services

Commands:
  create      Create a new service
  inspect     Display detailed information on one or more services
  logs        Fetch the logs of a service or task
  ls          List services
  ps          List the tasks of one or more services
  rm          Remove one or more services
  rollback    Revert changes to a service's configuration
  scale       Scale one or multiple replicated services
  update      Update a service

Run 'docker service COMMAND --help' for more information on a command.

• To use Docker Swarm, first of all, you have to create a stack that acts like "docker-compose." the commands begin with docker stack; let's list all of them.

ubuntu@ip-172-31-51-54:~$ docker stack --help

Usage:  docker stack COMMAND

Manage Swarm stacks

Commands:
  config      Outputs the final config file, after doing merges and interpolations
  deploy      Deploy a new stack or update an existing stack
  ls          List stacks
  ps          List the tasks in the stack
  rm          Remove one or more stacks
  services    List the services in the stack

Run 'docker stack COMMAND --help' for more information on a command.

Rolling Update

• When you want to release a new version of your application and deploy a new version to the server, the server should still be running anyway. so we use a rolling update.
• Note that the Docker Swarm commands can be used within Docker compose because Docker Swarm is included with Docker. 
• Now, let's edit Docker Combos a little:

version: "3"
services:
  node-app: 
    container_name: express-node-app-container
    image: mo201/node-app-docker
    ports: 
      - "4000:4000"
    env_file:
      - ./.env
    deploy:
      replicas: 4
      update_config:
        parallelism: 2
        delay: 10s
      restart_policy:
        condition: on-failure
        delay: 5s
    depends_on:
      - redis
      - mongo

  mongo:
   image: mongo
   restart: always
   volumes:
    - mongo-db:/data/db #Named volume
   environment:
     MONGO_INITDB_ROOT_USERNAME: root
     MONGO_INITDB_ROOT_PASSWORD: example    

  redis:
    image: redis
  
  nginx:
    image: nginx:stable-alpine
    ports:
    - "80:80"
    volumes:
      - ./nginx/default.conf:/etc/nginx/conf.d/default.conf
    depends_on:
      - node-app
volumes:
  mongo-db: 
  postgres-db:

• In the deploy section, you can see:

1. replicas
   • How many replicas do you want for this service?
2. update_config
   • Configures how the service should be updated.
   • parallelism: How many containers are updated at the same time?
3. restart_policy
   • Configures if and how to restart containers when they exit. There are many management and restriction options, of course; see Docker Docs.

• Let's go to the server side.

  • deploy new stack

   ubuntu@ip-172-31-51-54:~/naruto-server$ docker stack deploy -c docker-compose.yml -c docker-compose.prod.yml express-app
   Ignoring unsupported options: build, restart
  
   Ignoring deprecated options:
  
   container_name: Setting the container name is not supported.
  
   Creating network express-app_default
   Creating service express-app_mongo
   Creating service express-app_nginx
   Creating service express-app_node-app
   Creating service express-app_redis
  

  • list all stacks

  ubuntu@ip-172-31-51-54:~/naruto-server$ docker stack ls NAME SERVICES express-app 4

  • all services inside the stack

  ubuntu@ip-172-31-51-54:~/naruto-server$ docker stack services express-app
  ID             NAME                   MODE         REPLICAS   IMAGE                          PORTS
  xreuzburf8s6   express-app_mongo      replicated   1/1        mongo:latest                   
  i3p04051gloz   express-app_nginx      replicated   1/1        nginx:stable-alpine            *:80->80/tcp
  z15o796dlb5p   express-app_node-app   replicated   4/4        mo201/node-app-docker:latest   *:4000->4000/tcp
  flt2dby1rj5o   express-app_redis      replicated   1/1        redis:latest                   
  

  • list all running containers 

  ubuntu@ip-172-31-51-54:~/naruto-server$ docker stack ps express-app
  ID             NAME                      IMAGE                          NODE              DESIRED STATE   CURRENT STATE           ERROR                       PORTS
  j90bgqsojw3n   express-app_mongo.1       mongo:latest                   ip-172-31-51-54   Running         Running 6 minutes ago                               
  zyavh1sh7056   express-app_nginx.1       nginx:stable-alpine            ip-172-31-51-54   Running         Running 7 minutes ago                               
  040e20btmy9o    \_ express-app_nginx.1   nginx:stable-alpine            ip-172-31-51-54   Shutdown        Failed 7 minutes ago    "task: non-zero exit (1)"   
  oivkydzu0jdm   express-app_node-app.1    mo201/node-app-docker:latest   ip-172-31-51-54   Running         Running 7 minutes ago                               
  mqoozc9if55b   express-app_node-app.2    mo201/node-app-docker:latest   ip-172-31-51-54   Running         Running 7 minutes ago                               
  ohhnom2srsaf   express-app_node-app.3    mo201/node-app-docker:latest   ip-172-31-51-54   Running         Running 7 minutes ago                               
  v6rn7scd4ex3   express-app_node-app.4    mo201/node-app-docker:latest   ip-172-31-51-54   Running         Running 7 minutes ago                               
  b43fcx47pfze   express-app_redis.1       redis:latest                   ip-172-31-51-54   Running         Running 7 minutes ago                               
  

  • Now let's release a new vision for our app and see the rolling update.

    
    
    

Feel free to contribute to the repository if you find something wrong or have a better explanation.