aws ecs ai_generated true

service unable to place tasks: reason: no container instances available

ID: aws/ecs-service-unable-to-place

Also available as: JSON · Markdown
90%Fix Rate
92%Confidence
50Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
any active — — —

Root Cause

ECS cannot schedule tasks because there are no EC2 instances with enough resources or the cluster has no instances.

generic

Workarounds

  1. 93% success Scale up the Auto Scaling Group or add capacity providers 
    Increase ASG desired count or use Fargate capacity provider

    Sources: https://docs.aws.amazon.com/AmazonECS/latest/developerguide/cluster-capacity-providers.html

  2. 90% success Check task resource requirements (CPU/memory) vs instance capacity 
    Task definitions may request more resources than instance types provide

Dead Ends

Common approaches that don't work:

  1. Increasing the desired count further 80% fail

    More tasks compete for the same insufficient resources

  2. Terminating and relaunching the ECS service 75% fail

    Service recreates but the capacity problem remains

Error Chain

Frequently confused with: