devops-hand-skill

DevOps Expert Knowledge

CI/CD Pipeline Patterns

GitHub Actions Reference

Basic workflow structure:

name: CI/CD Pipeline
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Build
        run: make build
      - name: Test
        run: make test
      - name: Lint
        run: make lint

  deploy:
    needs: build
    if: github.ref == 'refs/heads/main'
    runs-on: ubuntu-latest
    steps:
      - name: Deploy
        run: make deploy

Useful API endpoints:

# List workflow runs
curl -s -H "Authorization: Bearer $GITHUB_TOKEN" \
  "https://api.github.com/repos/OWNER/REPO/actions/runs?per_page=10"

# Get workflow run details
curl -s -H "Authorization: Bearer $GITHUB_TOKEN" \
  "https://api.github.com/repos/OWNER/REPO/actions/runs/RUN_ID"

# Re-run failed jobs
curl -s -X POST -H "Authorization: Bearer $GITHUB_TOKEN" \
  "https://api.github.com/repos/OWNER/REPO/actions/runs/RUN_ID/rerun-failed-jobs"

Pipeline Optimization Checklist

• Cache dependencies (node_modules, .cargo, pip cache)
• Parallelize independent jobs
• Use matrix builds for multi-version testing
• Skip unnecessary steps on non-code changes
• Use shallow clones for faster checkout
• Optimize Docker layer caching
• Run expensive tests only on main branch

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Infrastructure Monitoring

Health Check Patterns

HTTP endpoint check:

curl -s -o /dev/null -w "%{http_code} %{time_total}s" --max-time 10 "$URL"

TCP port check:

nc -z -w5 hostname port && echo "UP" || echo "DOWN"

SSL certificate expiry:

echo | openssl s_client -servername HOST -connect HOST:443 2>/dev/null | \
  openssl x509 -noout -dates

DNS resolution:

dig +short hostname

Disk usage:

df -h | grep -v tmpfs

Memory usage:

free -h

The Four Golden Signals