multi-instance.yml

name: Deploy to multiple instances
# Dispatch a command to several instances in parallel and stream output per instance.
# SSM runs the command on all instances simultaneously — not sequentially.

on:
  push:
    branches: [main]

concurrency:
  group: deploy-${{ github.ref }}
  cancel-in-progress: false

jobs:
  deploy:
    name: Deploy
    runs-on: ubuntu-latest

    permissions:
      id-token: write
      contents: read

    steps:
      - name: Configure AWS credentials (OIDC)
        uses: aws-actions/configure-aws-credentials@ec61189d14ec14c8efccab744f656cffd0e33f37 # v6.1.0
        with:
          role-to-assume: arn:aws:iam::123456789012:role/my-deploy-role
          aws-region: us-east-1

      - name: Deploy to all app servers
        id: deploy
        uses: zAbuQasem/ssm-run-command@10be2ff3863ef31e5459092c0be8538fbc0907f8 # v2.0.0
        with:
          aws-region: us-east-1
          instance-ids: |
            ${{ secrets.INSTANCE_ID_1 }}
            ${{ secrets.INSTANCE_ID_2 }}
            ${{ secrets.INSTANCE_ID_3 }}
          working-directory: /home/ubuntu/app
          wait-for-output: true
          wait-timeout: 180
          comment: Deploy ${{ github.sha }}
          command: |
            git pull origin main
            npm install --production
            pm2 restart all

      # Output is prefixed per instance when targeting multiple: [i-xxxxx]\n<stdout>
      - name: Print per-instance output
        run: echo "${{ steps.deploy.outputs.output }}"