Serverless CRON Job | Overview.

Serverless CRON Job - Overview.

Scope:

• Intro,
• Architecture,
• Reasons Serverless is recommended for CRON Jobs,
• Key Components,
• AWS Example,
• Sample Schedule Expression,
• Cron job Use Cases,
• Benefits,
• Example of AWS Serverless CRON with Lambda.

Intro:

• A serverless CRON job refers to a scheduled task that runs in a serverless environment — without needing to manage any infrastructure.
• Serverless CRON Job leverages cloud services to execute code on a recurring schedule (e.g., every day at 8 AM). 
• Serverless CRON Job works similar to traditional CRON jobs in Linux systems.

 Architecture

Reasons Serverless  is recommended for CRON Jobs

Traditional CRON Jobs	Serverless CRON Jobs
Requires a server/VM.	No servers to manage
Uptime & patching needed.	Fully managed by cloud provider
Risk of job failure on reboot.	More resilient and reliable
Scaling is manual or complex.	Scales automatically

 Key Components

• Depending on twtech cloud provider, here’s how a serverless CRON job is generally set up:

 AWS Example

•         Scheduler: Amazon EventBridge Scheduler
•    Replaces older CloudWatch Events for CRON jobs.
•         Compute: AWS Lambda function
•         IAM Role: Provides permission for EventBridge to invoke Lambda

Sample Schedule Expression:

# cron

cron(0 8 * * ? *)   # Every day at 8 AM UTC

 Cron job Use Cases

•         Daily database backups
•         Email digests
•         Data processing or ETL jobs
•         Syncing data between services
•         Cleaning up unused resources

 Benefits

•         Cost-effective: Pay-per-use model
•         Highly available: No single point of failure
•         No maintenance: No servers or OS updates
•         Flexible: Integrates with other services (e.g., SNS, SQS, DynamoDB)

 Example of AWS Serverless CRON with Lambda

1.     Create a Lambda Function
Write a Python, Node.js, or Go function.

2.     Create an EventBridge Schedule

o   Console or Terraform/CDK/CloudFormation

o   Use CRON or rate expressions

3.     Set Permissions
Allow EventBridge to invoke twtech Lambda

4.     Monitor
Use CloudWatch Logs or set up alerts if job fails.