Demo – multiple runners on single instance #3
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| name: Demo – multiple runners on single instance | |
| on: | |
| workflow_dispatch: | |
| inputs: | |
| runners_per_instance: | |
| description: "Number of runners per EC2 instance" | |
| required: false | |
| type: string | |
| default: "3" | |
| sleep_duration: | |
| description: "Sleep duration in seconds for each job" | |
| required: false | |
| type: string | |
| default: "10" | |
| workflow_call: # Tested by `demos.yml` | |
| inputs: | |
| runners_per_instance: | |
| required: false | |
| type: string | |
| default: "3" | |
| sleep_duration: | |
| required: false | |
| type: string | |
| default: "10" | |
| permissions: | |
| id-token: write # Required for AWS OIDC authentication | |
| contents: read # Required for actions/checkout | |
| jobs: | |
| ec2: | |
| name: Launch 1 EC2 instance with ${{ inputs.runners_per_instance }} runners | |
| uses: ./.github/workflows/runner.yml | |
| secrets: inherit | |
| with: | |
| instance_name: "$repo/$name (#$run_number) – $idx" | |
| instance_count: "1" | |
| runners_per_instance: ${{ inputs.runners_per_instance }} | |
| ec2_image_id: ami-0e86e20dae9224db8 # Ubuntu 24.04 LTS x86_64 (us-east-1) | |
| # Use a larger instance type to handle multiple runners | |
| ec2_instance_type: t3.xlarge # 4 vCPUs, 16 GB RAM | |
| parallel-jobs: | |
| needs: ec2 | |
| strategy: | |
| matrix: | |
| # Parse the JSON array of runner labels and use them in the matrix | |
| runner: ${{ fromJson(needs.ec2.outputs.instances) }} | |
| runs-on: ${{ matrix.runner }} | |
| name: Job on ${{ matrix.runner }} | |
| steps: | |
| - uses: actions/checkout@v4 | |
| - name: Runner info | |
| run: | | |
| echo "Running on runner with label: ${{ matrix.runner }}" | |
| echo "Hostname: $(hostname)" | |
| echo "Instance ID: $(curl -s http://169.254.169.254/latest/meta-data/instance-id)" | |
| echo "Instance type: $(curl -s http://169.254.169.254/latest/meta-data/instance-type)" | |
| echo "Region: $(curl -s http://169.254.169.254/latest/meta-data/placement/region)" | |
| echo "Runner index: ${RUNNER_INDEX:-unknown}" | |
| echo "Runner home: ${RUNNER_HOME:-unknown}" | |
| - name: Simulate workload | |
| run: | | |
| # All runners on same instance run independently | |
| DURATION=${{ inputs.sleep_duration }} | |
| echo "Starting at: $(date '+%Y-%m-%d %H:%M:%S.%3N')" | |
| echo "Simulating workload for ${DURATION} seconds..." | |
| sleep $DURATION | |
| echo "Workload complete at: $(date '+%Y-%m-%d %H:%M:%S.%3N')" | |
| - name: Verify parallelism | |
| run: | | |
| echo "This job ran in parallel with other matrix jobs on the SAME instance" | |
| echo "With ${{ inputs.runners_per_instance }} runners and ${{ inputs.sleep_duration }}s sleep:" | |
| echo "- Sequential execution would take: $((${{ inputs.runners_per_instance }} * ${{ inputs.sleep_duration }}))s" | |
| echo "- Parallel execution should take: ~${{ inputs.sleep_duration }}s (plus overhead)" | |
| - name: Show resource sharing | |
| run: | | |
| echo "=== Resource Usage ===" | |
| echo "CPU cores available: $(nproc)" | |
| echo "Memory available: $(free -h | grep Mem | awk '{print $2}')" | |
| echo "Load average: $(uptime | awk -F'load average:' '{print $2}')" | |
| echo "" | |
| echo "Note: All ${{ inputs.runners_per_instance }} runners share these resources" |