Run HTTP Server as systemd process and automate it with github actions

Docker and kubernetes are great for automating deployment, scaling, and management of containerized applications. But it comes with extra cost of resource management. Often it is found that this processes itself would require some resources to run and execute the servers. We can totally avoid this complexity by using [systemd](https://en.wikipedia.org/wiki/Systemd) services. The name systemd adheres to the Unix convention of naming daemons by appending the letter d. It provides array of system components for linux operating system.

In this blog post we will see how we can deploy a NodeJS server on linux machine and automate the deployment with github actions. But it is not only limited to NodeJS ideally you can deploy any daemon/long running processes using systemd.

Quick demo

Let’s get started!

Step 1: Create a HTTP server or any long running process.

For the demo purpose let’s create a simple NodeJS server using Express.

Initialize node project npm init -y
Install dependencies npm install expres

Create index.js with following content

const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => {
  res.send('Hello World!')
})

app.listen(port, () => {
  console.log(`Example app listening at <http://localhost>:${port}`)
})

Add start script in package.json, scripts section
```
 "start": "node index.js"
```
Run npm start from the terminal & verify if the app is running or not.

Step 2: Create a virtual linux machine

In this tutorial we are going to use Google Cloud and Ubuntu to create a VM instance. You can use any provider and linux distribution here. Just the installation and creation commands can change!

Setup Virtual Machine For Google cloud users following is the command to create vm instance.

Note: Replace the PROJECT_NAME, SERVICE_ACCOUNT with your google cloud project and service accounts. Also you can set different machine type based on your traffic and processing.

gcloud beta compute --project=PROJECT_NAME instances create my-server --zone=us-central1-a --machine-type=e2-micro --subnet=default --network-tier=PREMIUM --maintenance-policy=MIGRATE --service-account=SERVICE_ACCOUNT --scopes=https://www.googleapis.com/auth/devstorage.read_only,<https://www.googleapis.com/auth/logging.write,https://www.googleapis.com/auth/monitoring.write,https://www.googleapis.com/auth/servicecontrol,https://www.googleapis.com/auth/service.management.readonly,https://www.googleapis.com/auth/trace.append> --tags=http-server,https-server --image=debian-10-buster-v20210512 --image-project=debian-cloud --boot-disk-size=10GB --boot-disk-type=pd-balanced --boot-disk-device-name=my-server --no-shielded-secure-boot --shielded-vtpm --shielded-integrity-monitoring --reservation-affinity=any

Enable requests on port 3000 for this instance

Note: for the demo purpose I am enabling port 3000 on all the instances in my Google account

gcloud compute --project=PROJECT_NAME firewall-rules create port-3000 --direction=INGRESS --priority=1000 --network=default --action=ALLOW --rules=tcp:3000 --source-ranges=0.0.0.0/0

ssh into the newly created VM

gcloud beta compute ssh --zone=us-central1-a "my-server"  --project=PROJECT_NAME

Install NodeJS

sudo apt-get update
curl -fsSL <https://deb.nodesource.com/setup_16.x> | sudo -E bash -
sudo apt-get install -y nodejs

Install wget for downloading source files

sudo apt-get install -y wget

Install unzip for extracting source

sudo apt-get install -y unzip

Step 3: Release the basic version and test the app

Download the zip from github

wget <https://github.com/lakhansamani/deployment-automation-demo/archive/refs/heads/main.zip>

Unzip the source

unzip main.zip

Install dependenceis

mv deployment-automation-demo-main demo && cd demo
npm install

Start node server

npm start

Open the instance IP:3000 in your browser and you will see Hello World

Now when your ssh connection will end this service will stop as it is not running as daemon process. In order to achieve this we will create a systemd process for the same

Step 4: Create `systemd` configuration file

We will create [demo.service](https://github.com/lakhansamani/deployment-automation-demo/blob/main/demo.service) file in our source code and use it with each deployment.

Note: Change service name, path to source and working directory.

demo.service

[Unit]
Description=demo

[Service]
Type=simple
Restart=always
RestartSec=5
ExecStart=/usr/bin/node /home/YOUR_SSH_USERNAME/demo/index.js
WorkingDirectory=/home/YOUR_SSH_USERNAME/demo/

[Install]
WantedBy=multi-user.target

There are more configurations that you can set here. Example memory requirements and environment variables. For more info you can check manual.

Step 5: Create shell script to deploy the latest release

Using shell script we will be performing following tasks.

Download the source based on release tag
Install the node dependencies
Start/Restart the systemd service

We can put this file in the home folder of our VM and can execute it using github actions.

This script takes 1 input argument, i.e. release tag/number

Note: Please change github path, repo name while unzipping it and service in the file below

deploy.sh

#!/bin/sh
if [ "$1" == "" ]; then
    echo "Please enter version"
    exit 1
fi

echo "upgrading demo to v-${1}"

# for private repos you can use wget with GithubToken in header
# example --header "Authorization: token ${GITHUB_TOKEN}"

wget <https://github.com/lakhansamani/deployment-automation-demo/archive/refs/tags/${1}.zip> -O demo.zip

# unzip
unzip demo.zip
mkdir -p demo
cp deployment-automation-demo-${1}/* demo/
rm -rf deployment-automation-demo-${1} demo.zip
cd demo
npm install

# Copy service file, incase if there are any changes
sudo cp demo.service /etc/systemd/system/demo.service
# reload configurations incase if service file has changed
sudo systemctl daemon-reload
# restart the service
sudo systemctl restart demo
# start of VM restart
sudo systemctl enable demo

Step 6: Create GitHub action

We want to run the shell script created in step 5 and restart system process on new the release.

Create .github/workflows folder in your source code

mkdir -p .github/workflows

Create .github/workflows/main.yml to run action

touch .github/workflows/main.yml

Add workflow to ssh into vm and run the deloy.sh script with correct release tag

Note: add ~/.ssh/google_compute_engine Private key in your github repository secret. Also add IP address as secret so that you don’t expose it unnecessarily. Also change SSH_USERNAME as per your VM

name: GitHub Actions Demo
on:
  release:
    types: [published]
jobs:
  Explore-GitHub-Actions:
    runs-on: ubuntu-latest
    steps:
      - name: Get the version
        id: get_version
        run: echo ::set-output name=VERSION::${GITHUB_REF/refs\\/tags\\//}
      - name: Debug version
        id: Debug
        run: echo ${{ steps.get_version.outputs.VERSION }}
      - name: executing remote ssh commands using ssh key
        uses: appleboy/ssh-action@master
        with:
          host: ${{ secrets.GCP_IP }}
          username: SSH_USERNAME
          key: ${{ secrets.GCP_PRIVATE_KEY }}
          port: 22
          script: /bin/sh deploy.sh ${{ steps.get_version.outputs.VERSION }}

Hurray! thats all we need. Now every time you create new release on github it will automatically deploy to you VM machine. You can also follow this process to deploy multiple services on single instance and achieve the micro service architecture here.

Here is a github repository that includes source for this demo.