Setting Up Zero-Downtime Deployment - Back-End Configuration
ServerHi, I’m Lovefield.
Following the previous article,”Setting Up Zero-Downtime Deployment - Environment Setup”, this post will describe the configuration for achieving zero-downtime deployment of the back-end server. The back-end framework used is Spring Boot, with Java as the runtime environment. Since building is the first priority, I will create build and upload functionality using Git Actions.
Before writing the Git Action, specify the secrets values required for the upload:
- HOST_DIR: The base directory location to be used on the server.
- HOST_IP: The server address.
- HOST_RUN_DIR: The directory location where scripts are executed on the server.
- HOST_USER: The server username.
- PEM_VALUE: The PEM key value for accessing the server.
prod-deploy.yml
YAML
name: Deploy
on:
push: # Executed when a push is made to the branch
branches:
- main
workflow_dispatch: # Manually executed from the GitHub Actions page
name:
description: "print name"
jobs:
buildAndDeploy:
runs-on: ubuntu-latest
permissions:
contents: read
packages: write
steps:
- uses: actions/checkout@v3
- uses: actions/setup-java@v4
with:
distribution: "temurin"
java-version: "21"
- name: Build
run: ./gradlew build
- name: Upload file
uses: appleboy/scp-action@v0.1.7
with:
host: ${{ secrets.HOST_IP }}
username: ${{ secrets.HOST_USER }}
key: ${{ secrets.PEM_VALUE }}
port: 22
source: "./build/libs/dico-4.0.jar"
target: ${{ secrets.HOST_DIR }}/
- name: Run Deploy Script
uses: appleboy/ssh-action@v1.1.0
env:
HOST_DIR: ${{ secrets.HOST_DIR }}
HOST_RUN_DIR: ${{ secrets.HOST_RUN_DIR }}
with:
host: ${{ secrets.HOST_IP }}
username: ${{ secrets.HOST_USER }}
key: ${{ secrets.PEM_VALUE }}
envs: HOST_DIR,HOST_RUN_DIR
port: 22
script: |
mv $HOST_DIR/build/libs/dico-4.0.jar $HOST_RUN_DIR/back/dico-4.0.jar
cd $HOST_RUN_DIR
sudo sh $HOST_RUN_DIR/deploy-backend.sh
After performing the build and upload using GitHub Actions, the configuration executes deploy-backend.sh on the server. This deploy-backend.sh script updates the Blue and Green containers.
deploy-backend.sh
Bash
#!/bin/bash
# Check if the Blue container is running
EXIST_BLUE=$(sudo docker compose ps -a | grep "backend-blue")
target="blue";
target_port="9002"
TIMESTAMP=`date +%Y%m`
LOGFILE="./logs/backend-$TIMESTAMP.log"
func_reload()
{
echo "[$(date +%Y-%m-%d\ %H\:%M\:%S)] $1 Container down" >> $LOGFILE
sudo docker compose down backend-$1
echo "[$(date +%Y-%m-%d\ %H\:%M\:%S)] $1 Container up" >> $LOGFILE
sudo docker compose up backend-$1 -d
sleep 1.5
while true; do
RESPONSE=$(curl -I http://localhost:$2/health-check | grep "200" | awk '{print $2}')
echo "[$(date +%Y-%m-%d\ %H\:%M\:%S)] $1 Container Health Check" >> $LOGFILE
if [ "$RESPONSE" -eq "200" ]; then
break;
fi
sleep 2
done
}
touch $LOGFILE
echo "[$(date +%Y-%m-%d\ %H\:%M\:%S)] >>> Start of the back-end deployment script <<<" >> $LOGFILE
# If the Blue container is running
if [ "$EXIST_BLUE" ]; then
target="green";
target_port="9001"
else
target="blue";
target_port="9002"
fi
func_reload $target $target_port
if [ "$target" -eq "blue" ]; then
func_reload "green" "9001"
else
func_reload "blue" "9002"
fi
echo "[$(date +%Y-%m-%d\ %H\:%M\:%S)] >>> End of the back-end deployment script <<<" >> $LOGFILE
After writing the script as described above, it can be executed either through a Git push or by manually creating an action. The process will proceed as follows:
Git Action builds the files based on the main branch.
Git Action transfers the built files to the server.
Git Action executes the deployment script on the server.
The deployment script unzips the received file and updates the Blue and Green containers respectively.
Once the process is complete, log files like the following will be generated in the logs folder
Plain Text
[2024-11-15 07:29:06] >>> Start of the back-end deployment script <<<
[2024-11-15 07:29:06] green Container down
[2024-11-15 07:29:06] green Container up
[2024-11-15 07:29:09] green Container Health Check
[2024-11-15 07:29:11] green Container Health Check
[2024-11-15 07:29:13] green Container Health Check
[2024-11-15 07:29:15] green Container Health Check
[2024-11-15 07:29:17] green Container Health Check
[2024-11-15 07:29:19] green Container Health Check
[2024-11-15 07:29:19] blue Container down
[2024-11-15 07:29:20] blue Container up
[2024-11-15 07:29:22] blue Container Health Check
[2024-11-15 07:29:24] blue Container Health Check
[2024-11-15 07:29:26] blue Container Health Check
[2024-11-15 07:29:28] blue Container Health Check
[2024-11-15 07:29:30] blue Container Health Check
[2024-11-15 07:29:30] >>> End of the back-end deployment script <<<
With this, the back-end deployment configuration is complete.
