Part 2 - Dockerise your Blockchain app

In the previous article, we've built an Ethereum blockchain on AWS using Ganache-CLI. The blockchain is up but it requires to be manually started with your terminal tab always running ganache. What if we can have the blockchain running in background on the EC2 server, and add a custom domain to its IP address, and then secure it with an API token. So that's what we will be working on in this part.

Here is where Docker comes in.

Containerise your blockchain app

Docker is useful when you need to run an app pre installed with all its dependencies.

1. ssh into your EC2 instance and install docker by running these commands
   

   $ sudo apt-get update
   
   $ sudo apt-get install \
       apt-transport-https \
       ca-certificates \
       curl \
       gnupg \
       lsb-release
   
   $ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
   
   $ echo \
   "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
   
   $ sudo apt-get update
   
   $ sudo apt-get install docker-ce docker-ce-cli containerd.io
   
   $ sudo docker run hello-world
   

   You should be able to see this output after the last command.

   

2. Create a Dockerfile

   Create a new file named Dockerfile at your current folder. In the file add these lines,
   

   # node:alpine will be our base image to create this image
   FROM node:alpine
   
   # Set the /app directory as working directory
   WORKDIR /app
   
   # Install ganache-cli globally
   RUN npm install -g ganache-cli
   
   EXPOSE 8545
   
   # Set the default command for the image
   CMD ["ganache-cli", "-h", "0.0.0.0", "--port", "8545", "--networkId", "5777"] 
   

3. Build and run Dockerfile

   We are now ready to build and run the blockchain in the background!
   

   # Builds the docker image with the name ganache
   sudo docker build -t ganache .
   
   # runs the app. -d will detach the app so that it will in background
   sudo docker run -d -p 8545:8545 ganache
   
   # checks if ganache has run successfully
   sudo docker logs ganache
   

Your app is up and running!

Visit your AWS public IP on port 8545 (http://<YOUR_EC2_IP_ADDRESS>:8545).