desiredCount, Amazon ECS spawns another instantiation of the task in the specified cluster. To update an existing service, see UpdateService.
You can optionally specify a deployment configuration for your service. During a deployment
(which is triggered by changing the task definition of a service with an UpdateService
operation), the service scheduler uses the
maximumPercent parameters to determine the deployment strategy.
minimumHealthyPercent is below 100%, the scheduler can ignore
desiredCount temporarily during a deployment. For example, if your
service has a
desiredCount of four tasks, a
of 50% allows the scheduler to stop two existing tasks before starting two new tasks.
Tasks for services that do not use a load balancer are considered healthy if
they are in the
RUNNING state; tasks for services that do use
a load balancer are considered healthy if they are in the
and the container instance it is hosted on is reported as healthy by the load balancer.
The default value for
minimumHealthyPercent is 50% in the console and
100% for the AWS CLI, the AWS SDKs, and the APIs.
maximumPercent parameter represents an upper limit on the number
of running tasks during a deployment, which enables you to define the deployment batch
size. For example, if your service has a
desiredCount of four tasks,
maximumPercent value of 200% starts four new tasks before stopping
the four older tasks (provided that the cluster resources required to do this are
available). The default value for
maximumPercent is 200%.
When the service scheduler launches new tasks, it attempts to balance them across the Availability Zones in your cluster with the following logic:
Determine which of the container instances in your cluster can support your service's task definition (for example, they have the required CPU, memory, ports, and container instance attributes).
Sort the valid container instances by the fewest number of running tasks for this service in the same Availability Zone as the instance. For example, if zone A has one running service task and zones B and C each have zero, valid container instances in either zone B or C are considered optimal for placement.
Place the new service task on a valid container instance in an optimal Availability Zone (based on the previous steps), favoring container instances with the fewest number of running tasks for this service.
Version: (assembly version)
public abstract CreateServiceResponse CreateService( CreateServiceRequest request )
Container for the necessary parameters to execute the CreateService service method.
|ClientException||These errors are usually caused by a client action, such as using an action or resource on behalf of a user that doesn't have permission to use the action or resource, or specifying an identifier that is not valid.|
|ClusterNotFoundException||The specified cluster could not be found. You can view your available clusters with ListClusters. Amazon ECS clusters are region-specific.|
|InvalidParameterException||The specified parameter is invalid. Review the available parameters for the API request.|
|ServerException||These errors are usually caused by a server issue.|
Supported in: 4.5, 4.0, 3.5