Why Zero-Downtime Deployment Matters
Traditional deployment methods require taking your application offline during updates, causing revenue loss and poor user experience. Zero-downtime deployment solves this with blue-green or rolling update strategies.
Architecture Overview
Our setup uses two identical environments (blue and green). Traffic is routed to one while the other is updated. After health checks pass, traffic switches instantaneously.
GitHub Actions Workflow
name: Deploy\non:\n push:\n branches: [main]\njobs:\n deploy:\n runs-on: ubuntu-latest\n steps:\n - uses: actions/checkout@v4\n - name: Build Docker image\n run: docker build -t myapp:${{ github.sha }} .\n - name: Push to registry\n run: docker push myapp:${{ github.sha }}\n - name: Deploy with rolling update\n run: kubectl set image deployment/myapp app=myapp:${{ github.sha }}Health Checks
Always configure readiness probes in Kubernetes. Your application should return HTTP 200 on /health only when it is fully ready to serve traffic, including database connectivity verification.