GeeksHacking Workshop - Dealing with Containerization

Organized by GeeksHacking, the workshop is conducted by @chukmunnlee on 7th September 2019.

Check out Chuk's Presentation Slides, and the Event Details if you are curious to find out more about it!

These notes are contributed by @lyqht, a random participant who enjoyed the workshop.

About the Repo

In this workshop, we will deploy two apps that can be found in this repo. A basic Fortune Cookie Web app in /fortune and a slightly more complicated Leisure Mobile app that has a database in /frontend+/backend+/data.

The finished dockerfiles and docker-compose.yml file for the two projects are located in their respective folders under /deployments. But the difficulty of this workshop is not reading what is in the docker related files, but running the docker commands appropriately and understanding what they do. ;)

Table of Contents

• GeeksHacking Workshop - Dealing with Containerization
  • About the Repo
  • Table of Contents
  • Setup instructions
    • Deploying a remote VM Instance (UpCloud)
      • Generate SSH Keys
      • Choose a cloud service provider & choose an instance to deploy
    • Creating and Running A Remote Docker Machine
      • Login to Docker
  • Deploy the Fortune Cookie App
    • Building the Docker Image for the App
    • Deploying the docker image
    • Cleaning up
  • Deploying the Leisure App
    • Network & Volumes [not covered in detail]

Setup instructions

Prepare an empty folder e.g. docker_workshop somewhere that will store this repository and the ssh keypair that you will be creating.

For basic docker setup, please refer to GeeksHacking's manual.

Deploying a remote VM Instance (UpCloud)

Generate SSH Keys

Before deploying an instance, you would need set up a ssh public & private keypair, to allow connection between your local machine and the remote instance. Open up your terminal and cd into docker_workshop, then create the keypair here with this command.

ssh-keygen

The name of the keypair files are up to you. For the convenience of learning, don't put a password for now as it will shorten the commands that you need to type later on.

Two files will be produced with this command.

1. The private key is the file without any extension.
2. The public key is the file with the .pub extension, and its contents are what you need to attach to the remote instance later on. To read the contents, open it up with a text editor/code editor or echo SSH_KEY_NAME.pub if you are in linux.

Choose a cloud service provider & choose an instance to deploy

For this workshop, the remote server is deployed via UpCloud, but you can use other cloud services as well so long as the capability of the instance meets the minimum requirement for deploying the applications in this repository.

The UpCloud instance's specs:

• Location: SG
• Plan: $10/mth (1cores, 2GB Memory, 50GB storage)
• Storage: VirtIO(default), MaxIOPS, 10GB
• OS: Ubuntu Server 18.04 LTS
• Optionals: IPv6 YES
• SSH_KEY: NOT PRIVATE, Click ADD NEW+ then copy and paste the contents that you saw earlier on in the public key.
• Initialization Script: NIL
• Hostname: whatever you want

Deploying takes a few minutes, after which you can obtain its IP address for connecting to it and visiting the web app that you have deployed later on. You will also be notified of the password to access the instance (not used in this workshop.)

To connect to a remote server instance, run this command in the terminal under docker_workshop

ssh root@94.237.78.166 -i SSH_KEY_NAME

You will see that your terminal prompt has changed to root@YOUR_INSTANCE_HOSTNAME.

To disconnect, key exit in the terminal.

Creating and Running A Remote Docker Machine

Create a docker machine with the remote server's IP address and the public SSH Key that you attached to it.

docker-machine create \
    --driver generic \
    --generic-ip-address=YOUR_INSTANCE_IP_ADDRESS \
    --generic-ssh-key SSH_KEY_NAME mydockermachine

Then run the command below to see the configuration of your docker machine. You will also see there are 2 comments included in the output. The output you see will differ depending on your OS.

docker-machine env mydockermachine

Copy the last line comment without the # into the terminal. This is a command that will configure the shell to issue docker commands that you run in your local computer machine directly to the remote server.

Login to Docker

docker login

Deploy the Fortune Cookie App

Building the Docker Image for the App

Get a node.js image from Docker Hub.

docker pull node:latest

After we downloaded the image, we can check for the list of images that our docker machine has.

docker images

This image will serve as the base image upon which we will add files that our web app requires. To add the files to the image, we will need to create a dockerfile in the /fortune app folder.

For the dockerfile, please refer to deployments/fortune/Dockerfile. You can either copy line by line to understand what it is trying to do or just copy it over. After which, you can run a docker command inside the /fortune folder to build it. You can name the image anything, it is similar to naming a git repo.

docker build -t lyqht/fcookie:v1

Please replace lyqht/fcookie with YOUR_DOCKER_USERNAME/YOUR_IMAGE_NAME. it's just an example.

To check if the build is successful, in addition to seeing the success message prompt, you can check the list of docker images again and see your newly created image.

Deploying the docker image

For a github repo, for other computers/users to access your repo, you need to push it to a place that can host your repo. Likewise for docker images to be accessed by other instances, we will push the image to docker hub.

docker push DOCKER_USERNAME/IMAGE_NAME:v1

This step will fail if you are not logged in previously.

After you have pushed the docker image, you can check that your image is now on dockerhub.

Then, you can issue a docker command for the remote instance to start a container that runs the image.

docker run -d -p 80:3000 --name app1 DOCKER_USERNAME/IMAGE_NAME:v1

80:3000 refers to Mapping TCP port 80 in the container to port 3000 on the Docker host.

To check the list of docker containers

docker ps

Now, when you visit the public IP of your instance, you will see the Fortune Cookie Website!

Cleaning up

You can stop an image from running.

docker stop IMAGE_ID_OR_NAME

But the image will still remain, as you check the list of images, including those that are inactive with docker images -a. If you don't require it anymore, you can remove it.

docker rmi IMAGE_ID_OR_NAME

If you're lazy to stop it before removing it run docker rmi -f IMAGE_ID_OR_NAME

Likewise for the container, if you do not require it anymore, you can remove it.

docker rm CONTAINER_ID_OR_NAME

Deploying the Leisure App

For the backend, an SQL Image is required (you can get from docker hub similarly as Nodejs) and a dockerfile needs to be created for the backend. You can refer to /deployments/backend/Dockerfile for it.

To build the image for the database... it's the same as building it for the fortune cookie app!

docker build -t lyqht/leisuredb:v1

Except this time we do not push this image alone, since the leisure app is not complete yet. We would need another Dockerfile and a docker-compose.yml to integrate the backend image with the frontend stuff. You can refer to deployments/Dockerfile and deployments/docker-compose.yml respectively. These files should be placed directly in the root folder of the repository.

In docker-compose.yml, remember to change the name of the backend image to the one that you have created.

Network & Volumes [not covered in detail]

As you navigate these files, you would see new terms such as network and volumes, and yes there also docker commands on how to create them!

To create a network

docker network create appnet

To create a volume

docker volume create myvol

Attach a specified volume to a specified network for the backend image to run on.

docker run -d -p 3306:3306 --network mynet --volume myvol --name db lyqht/leisuredb:v1

Unfortunately, the concepts of networks and volumes are not covered in detail for the workshop due to lack of time.

In the docker-compose.yml, You would also see that the files depend on a config.json, change the name of the existing config_template.json to match. After you are done, you can compose the build from the root folder.

docker-compose build

Now you can once again push the app and run it in a new container in your remote instance.

AND YOU'RE DONE~ :) Thanks Chuk for the great workshop.