Deployment and Automation · Topic 6 of 7
Scheduled and Event Driven Automation
Automate operations with EventBridge Scheduler, Lambda, Step Functions, Automation runbooks, tags, Config remediation and AWS Service Catalog.
- 4 min
- EventBridge scheduled rules use UTC, and EventBridge Scheduler adds time zones and one time schedules.
- Scheduler universal targets can call AWS APIs directly, such as start and stop instances.
- Lambda handles small custom tasks and needs an execution role.
What it is
Operations work often repeats: stop test servers at night, tag new resources, clean up old snapshots, react to a change. AWS lets you automate these tasks with a schedule or an event, so no engineer has to remember them.
The skill the exam tests is choosing the lightest service that does the job: a built in scheduler, a small Lambda function, a runbook, or a managed rule.
How it works
Schedules
Amazon EventBridge has two ways to run something on a time basis. A scheduled rule on the event bus uses cron or rate expressions in UTC. EventBridge Scheduler is the newer service, with one time and recurring schedules, time zone support and a flexible time window.
Scheduler offers universal targets, which call many AWS APIs directly. You can stop and start EC2 instances on a timetable without writing a function.
| Need | Choice |
|---|---|
| Time based trigger in a chosen time zone | EventBridge Scheduler |
| React to an AWS event | EventBridge rule with an event pattern |
| Custom logic with code | Lambda function |
| Several steps with branching and retries | Step Functions |
| Standard repair steps on AWS resources | Systems Manager Automation runbook |
Lambda for operations
A Lambda function with an execution role can run a script on demand. It suits small tasks such as tagging a new resource from event data or deleting snapshots older than a set age. Keep the role narrow, since the function acts with its own permissions.
# AWS CLI: one time schedule that triggers a function
aws scheduler create-schedule \
--name cleanup-once \
--schedule-expression "at(2026-12-01T03:00:00)" \
--flexible-time-window Mode=OFF \
--target '{"Arn":"arn:aws:lambda:us-east-1:111122223333:function:cleanup","RoleArn":"arn:aws:iam::111122223333:role/scheduler-role"}'Step Functions and runbooks
Step Functions orchestrates longer workflows with branching, waits and retries. Systems Manager Automation runbooks do similar work, with ready made actions for AWS operations and approval steps. Choose runbooks for common ops tasks, and Step Functions for application style workflows.
Event driven fixes
EventBridge rules can match events such as an instance state change, a CloudTrail API call or an AWS Health notice, and send them to a target. AWS Config can check resources against a rule and trigger an automatic remediation action, which runs an Automation runbook.
A typical example is a Config rule that finds an S3 bucket without encryption, and a remediation that turns encryption on.
Tags and resource groups
Tags are key and value labels on resources. They drive cost allocation, access control, backup selection and automation targets. A Resource Group collects resources that share tags, and Systems Manager can act on the group.
Tag Editor finds and changes tags in bulk across Regions.
Consistent tags are only useful if they are enforced. Tag policies in AWS Organizations define allowed keys and values, and Config rules can flag missing tags.
Governed self service
AWS Service Catalog lets administrators publish approved CloudFormation templates as products in portfolios. Users launch them without direct permission to create the underlying resources, and constraints can fix settings such as the instance size. This keeps provisioning fast and compliant.
Lifecycle automation inside services
Many services can manage their own cleanup. S3 lifecycle rules transition or expire objects, Data Lifecycle Manager handles EBS snapshots, and DynamoDB can expire items with a time to live attribute. Use these built in features before writing custom code.
If the task is "run at a time", think a schedule. If it is "when X happens", think an event. If a managed feature already does it, such as S3 lifecycle rules, prefer that over custom code.
What to remember for the exam
- EventBridge scheduled rules use UTC, and EventBridge Scheduler adds time zones and one time schedules.
- Scheduler universal targets can call AWS APIs directly, such as start and stop instances.
- Lambda handles small custom tasks and needs an execution role.
- Step Functions suits multi step workflows, and Automation runbooks suit standard AWS operations tasks.
- Config rules detect non compliance, and remediation can run an Automation runbook.
- Tags drive cost allocation, automation and access control, and tag policies enforce them.
- Service Catalog gives governed self service from approved templates.
- Prefer built in lifecycle features (S3, DLM, DynamoDB TTL) over custom scripts.
Common mistakes
Writing code when a feature exists. Lifecycle rules and Scheduler targets need no function.
Reading cron in local time. Scheduled rules use UTC. Convert the time or use Scheduler with a time zone.
Giving the automation a wide role. An over broad execution role turns a small bug into a large incident.
Inconsistent tags. Env=prod and env=production break tag based targeting.
Remediating without a limit. An automatic fix that fails and retries forever can loop.
Automation that deletes resources should run in report mode first. Log what it would delete, review the list, then enable the deletion.
Check yourself
Quick questions.
How can you stop dev instances every evening without code?
Use EventBridge Scheduler with a universal target that calls the EC2 stop API.
Which service orchestrates multi step workflows with retries?
AWS Step Functions.
What enforces allowed tag keys and values across accounts?
Tag policies in AWS Organizations.
Topic 6 of 7 in Deployment and Automation
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