This is 1/3 response to a short prompt about implementation options for GitHub Runner form broken Server to Github Enterprise Cloud: # EC2-Based GitHub Actions Self-Hosted Runners - Complete Implementation

## Architecture Overview

This solution deploys auto-scaling GitHub Actions runners on EC2 instances that can trigger your existing AWS CodeBuild pipelines. Runners are managed via Auto Scaling Groups with automatic registration and health monitoring.

## Prerequisites

- AWS CLI configured with appropriate credentials - GitHub Enterprise Cloud organization admin access - Existing CodeBuild project(s) - VPC with public/private subnets

## Solution Components

### 1. CloudFormation Template### 2. GitHub Workflow for CodeBuild Integration## Deployment Steps

### Step 1: Create GitHub Personal Access Token

1. Navigate to GitHub → Settings → Developer settings → Personal access tokens → Fine-grained tokens 2. Create token with these permissions: - *Repository permissions:* - Actions: Read and write - Metadata: Read - *Organization permissions:* - Self-hosted runners: Read and write

```bash # Store token securely export GITHUB_PAT="ghp_xxxxxxxxxxxxxxxxxxxx" export GITHUB_ORG="your-org-name" ```

### Step 2: Deploy CloudFormation Stack

```bash # Set variables export AWS_REGION=us-east-1 export STACK_NAME=github-runner-ec2 export VPC_ID=vpc-xxxxxxxx export SUBNET_IDS="subnet-xxxxxxxx,subnet-yyyyyyyy"

# Deploy stack aws cloudformation create-stack \ --stack-name $STACK_NAME \ --template-body file://github-runner-ec2-asg.yaml \ --parameters \ ParameterKey=VpcId,ParameterValue=$VPC_ID \ ParameterKey=PrivateSubnetIds,ParameterValue=\"$SUBNET_IDS\" \ ParameterKey=GitHubOrganization,ParameterValue=$GITHUB_ORG \ ParameterKey=GitHubPAT,ParameterValue=$GITHUB_PAT \ ParameterKey=InstanceType,ParameterValue=t3.medium \ ParameterKey=MinSize,ParameterValue=2 \ ParameterKey=MaxSize,ParameterValue=10 \ ParameterKey=DesiredCapacity,ParameterValue=2 \ ParameterKey=RunnerLabels,ParameterValue="self-hosted,linux,x64,ec2,aws,codebuild" \ ParameterKey=CodeBuildProjectNames,ParameterValue="" \ --capabilities CAPABILITY_NAMED_IAM \ --region $AWS_REGION

# Wait for completion (5-10 minutes) aws cloudformation wait stack-create-complete \ --stack-name $STACK_NAME \ --region $AWS_REGION

# Get stack outputs aws cloudformation describe-stacks \ --stack-name $STACK_NAME \ --query 'Stacks[0].Outputs' \ --region $AWS_REGION ```

### Step 3: Verify Runners

```bash # Check Auto Scaling Group ASG_NAME=$(aws cloudformation describe-stacks \ --stack-name $STACK_NAME \ --query 'Stacks[0].Outputs[?OutputKey==`AutoScalingGroupName`].OutputValue' \ --output text)

aws autoscaling describe-auto-scaling-groups \ --auto-scaling-group-names $ASG_NAME \ --region $AWS_REGION

# List running instances aws ec2 describe-instances \ --filters "Name=tag:aws:autoscaling:groupName,Values=$ASG_NAME" \ --query 'Reservations[].Instances[].[InstanceId,State.Name,PrivateIpAddress]' \ --output table

# Check CloudWatch logs aws logs tail /github-runner/instances --follow ```

### Step 4: Verify in GitHub

Navigate to: `https://github.com/organizations/YOUR_ORG/settings/actions/r...`

You should see your EC2 runners listed as "Idle" with labels: `self-hosted, linux, x64, ec2, aws, codebuild`

## Using One Runner for Multiple Repos & Pipelines

### Organization-Level Runners (Recommended)

EC2 runners registered at the organization level can serve all repositories automatically.

*Benefits:* - Centralized management - Cost-efficient resource sharing - Simplified scaling - Single point of monitoring

*Configuration in CloudFormation:* The template already configures organization-level runners via the UserData script: ```bash ./config.sh --url "https://github.com/${GitHubOrganization}" ... ```

### Multi-Repository Workflow Examples### Advanced: Runner Groups for Access Control### Label-Based Runner Selection Strategy

*Create different runner pools with specific labels:*

```bash # Production runners RunnerLabels: "self-hosted,linux,ec2,production,high-performance"

# Development runners RunnerLabels: "self-hosted,linux,ec2,development,general"

# Team-specific runners RunnerLabels: "self-hosted,linux,ec2,team-platform,specialized" ```

*Use in workflows:*

```yaml jobs: prod-deploy: runs-on: [self-hosted, linux, ec2, production]

  dev-test:
    runs-on: [self-hosted, linux, ec2, development]
  
  platform-build:
    runs-on: [self-hosted, linux, ec2, team-platform]

```bash # Check Auto Scaling Group health aws autoscaling describe-auto-scaling-groups \ --auto-scaling-group-names $ASG_NAME \ --query 'AutoScalingGroups[0].[DesiredCapacity,MinSize,MaxSize,Instances[].[InstanceId,HealthStatus,LifecycleState]]'

# View instance system logs INSTANCE_ID=$(aws autoscaling describe-auto-scaling-groups \ --auto-scaling-group-names $ASG_NAME \ --query 'AutoScalingGroups[0].Instances[0].InstanceId' \ --output text)

aws ec2 get-console-output --instance-id $INSTANCE_ID

# Check CloudWatch logs aws logs get-log-events \ --log-group-name /github-runner/instances \ --log-stream-name $INSTANCE_ID/runner \ --limit 50 ```

### Connect to Runner Instance (via SSM)

```bash # List instances aws autoscaling describe-auto-scaling-groups \ --auto-scaling-group-names $ASG_NAME \ --query 'AutoScalingGroups[0].Instances[].[InstanceId,HealthStatus]' \ --output table

# Connect via Session Manager (no SSH key needed) aws ssm start-session --target $INSTANCE_ID

# Once connected, check runner status sudo systemctl status actions.runner. sudo journalctl -u actions.runner.* -f ```

### Troubleshooting Common Issues## Advanced Scaling Configuration

### Lambda-Based Dynamic Scaling

For more sophisticated scaling based on GitHub Actions queue depth:### Deploy Scaling Lambda

```bash # Create Lambda function zip function.zip github-queue-scaler.py

aws lambda create-function \ --function-name github-runner-scaler \ --runtime python3.11 \ --role arn:aws:iam::ACCOUNT_ID:role/lambda-execution-role \ --handler github-queue-scaler.lambda_handler \ --zip-file fileb://function.zip \ --timeout 30 \ --environment Variables="{ ASG_NAME=$ASG_NAME, GITHUB_ORG=$GITHUB_ORG, GITHUB_TOKEN=$GITHUB_PAT, MAX_RUNNERS=10, MIN_RUNNERS=2 }"

# Create CloudWatch Events rule to trigger every 2 minutes aws events put-rule \ --name github-runner-scaling \ --schedule-expression 'rate(2 minutes)'

aws events put-targets \ --rule github-runner-scaling \ --targets "Id"="1","Arn"="arn:aws:lambda:REGION:ACCOUNT:function:github-runner-scaler" ```

## Cost Optimization

### 1. Use Spot Instances

Add to Launch Template in CloudFormation:

```yaml LaunchTemplateData: InstanceMarketOptions: MarketType: spot SpotOptions: MaxPrice: "0.05" # Set max price SpotInstanceType: one-time ```

### 2. Scheduled Scaling

Scale down during off-hours:

```bash # Scale down at night (9 PM) aws autoscaling put-scheduled-action \ --auto-scaling-group-name $ASG_NAME \ --scheduled-action-name scale-down-night \ --recurrence "0 21 * * " \ --desired-capacity 1

# Scale up in morning (7 AM) aws autoscaling put-scheduled-action \ --auto-scaling-group-name $ASG_NAME \ --scheduled-action-name scale-up-morning \ --recurrence "0 7 * MON-FRI" \ --desired-capacity 3 ```

### 3. Instance Type Mix

Use multiple instance types for better availability and cost:

```yaml MixedInstancesPolicy: InstancesDistribution: OnDemandBaseCapacity: 1 OnDemandPercentageAboveBaseCapacity: 25 SpotAllocationStrategy: price-capacity-optimized LaunchTemplate: Overrides: - InstanceType: t3.medium - InstanceType: t3a.medium - InstanceType: t2.medium ```

## Security Best Practices

1. *No hardcoded credentials* - Using Secrets Manager for GitHub PAT 2. *IMDSv2 enforced* - Prevents SSRF attacks 3. *Minimal IAM permissions* - Scoped to specific CodeBuild projects 4. *Private subnets* - Runners not directly accessible from internet 5. *SSM for access* - No SSH keys needed 6. *Encrypted secrets* - Secrets Manager encryption at rest 7. *CloudWatch logging* - All runner activity logged

## References

- [GitHub Self-hosted Runners Documentation](https://docs.github.com/en/actions/hosting-your-own-runners/...) - [GitHub Runner Registration API](https://docs.github.com/en/rest/actions/self-hosted-runners) - [AWS Auto Scaling Documentation](https://docs.aws.amazon.com/autoscaling/ec2/userguide/what-i...) - [AWS CodeBuild API Reference](https://docs.aws.amazon.com/codebuild/latest/APIReference/We...) - [GitHub Actions Runner Releases](https://github.com/actions/runner/releases) - [AWS Systems Manager Session Manager](https://docs.aws.amazon.com/systems-manager/latest/userguide...)

This solution provides a production-ready, cost-effective EC2-based runner infrastructure with automatic scaling, comprehensive monitoring, and multi-repository support for triggering CodeBuild pipelines.