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John Ajera
John Ajera

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Running an ECS Task Manually on EC2

#aws #ecs #cli #devops

Sometimes I just want to run an ECS task on demand, not wait for EventBridge or a service.
This is how I do it for classic EC2-based ECS clusters (not Fargate).

🧠 When to use this

  • For ad-hoc maintenance jobs (like log cleanup or data processing)
  • To manually trigger an ECS task that’s normally run by EventBridge
  • When testing a new task definition before automating it

⚙️ Prerequisites

  • ECS cluster already exists and is EC2-based
  • A task definition (family or ARN)
  • IAM permissions to run ECS tasks

Check the cluster type:

aws ecs describe-clusters --clusters cluster1
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🚀 Run the task manually

Minimal command:

aws ecs run-task \
  --cluster cluster1 \
  --task-definition arn:aws:ecs:ap-southeast-2:111122223333:task-definition/my-task:134 \
  --count 1 \
  --launch-type EC2 \
  --region ap-southeast-2
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That immediately starts the task on one of your ECS container instances.

🧩 Check task status

List recent tasks:

aws ecs list-tasks --cluster cluster1
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Describe a task:

aws ecs describe-tasks --cluster cluster1 --tasks <task-id>
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Stop a running task:

aws ecs stop-task --cluster cluster1 --task <task-id>
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📝 Notes

  • --launch-type EC2 ensures it runs on existing container instances
  • --enable-execute-command allows you to connect using aws ecs execute-command
  • No network configuration is required for EC2 launch type
  • Task permissions and env vars come from the task definition

✅ Summary

Quick reminder for myself:

  • Use aws ecs run-task for manual ECS jobs
  • Works well for debugging, testing, or one-off operations
  • Keep it simple — no EventBridge required

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