How to enable Availability Zone Rebalancing with JSON?

[ikegentz]

I have a variety of ECS services that I manage with JSON templates. CI runs these and updates my services using aws ecs update-service --cli-input-json ...

I would like to enable Availability Zone Rebalancing. I see availabilityZoneRebalancing as an option in --generate-cli-skeleton for aws ecs create-service, but no such option for aws ecs update-service, despite aws-ecs update-service supporting --availability-zone-rebalancing as a flag.

Is there a way to manage this setting via JSON for an existing ECS service?

[uldyssian-sh]

Yes. availabilityZoneRebalancing is an UpdateService request parameter, so you can manage it via --cli-input-json by including the field in your JSON.

Even if aws ecs update-service --generate-cli-skeleton doesn’t show it in your CLI version, the API (and the CLI flag) supports it, and the CLI will pass it through as long as the key matches the API field name.

Example JSON for update-service:

{
"cluster": "my-cluster",
"service": "my-service",
"availabilityZoneRebalancing": "ENABLED"
}

Run it like this:

aws ecs update-service --cli-input-json file://update.json

Alternatively, if you prefer to keep your JSON unchanged, you can set it as a CLI override alongside the JSON:

aws ecs update-service
--cli-input-json file://update.json
--availability-zone-rebalancing ENABLED

To confirm the setting after the update:

aws ecs describe-services
--cluster my-cluster
--services my-service
--query "services[0].availabilityZoneRebalancing"
--output text

Notes:

This setting does not trigger a new deployment, and for updates the default is “keep existing value”; if it was never set before, ECS treats it as DISABLED unless you explicitly set it to ENABLED.

[uldyssian-sh]

Thanks! If this helps, please consider marking it as “Helpful” or “Accepted” 😊