amazonka-ecs-1.6.1: Amazon EC2 Container Service SDK.

Copyright (c) 2013-2018 Brendan Hay Mozilla Public License, v. 2.0. Brendan Hay auto-generated non-portable (GHC extensions) None Haskell2010

Description

Modifies the desired count, deployment configuration, network configuration, or task definition used in a service.

You can add to or subtract from the number of instantiations of a task definition in a service by specifying the cluster that the service is running in and a new desiredCount parameter.

If you have updated the Docker image of your application, you can create a new task definition with that image and deploy it to your service. The service scheduler uses the minimum healthy percent and maximum percent parameters (in the service's deployment configuration) to determine the deployment strategy.

You can also update the deployment configuration of a service. When a deployment is triggered by updating the task definition of a service, the service scheduler uses the deployment configuration parameters, minimumHealthyPercent and maximumPercent , to determine the deployment strategy.

• If minimumHealthyPercent is below 100%, the scheduler can ignore desiredCount temporarily during a deployment. For example, if desiredCount is four tasks, a minimum 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 use a load balancer are considered healthy if they are in the RUNNING state and the container instance they are hosted on is reported as healthy by the load balancer.
• The 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 desiredCount is four tasks, a maximum of 200% starts four new tasks before stopping the four older tasks (provided that the cluster resources required to do this are available).

When UpdateService stops a task during a deployment, the equivalent of docker stop is issued to the containers running in the task. This results in a SIGTERM and a 30-second timeout, after which SIGKILL is sent and the containers are forcibly stopped. If the container handles the SIGTERM gracefully and exits within 30 seconds from receiving it, no SIGKILL is sent.

When the service scheduler launches new tasks, it determines task placement 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).
• By default, the service scheduler attempts to balance tasks across Availability Zones in this manner (although you can choose a different placement strategy):
• 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.

When the service scheduler stops running tasks, it attempts to maintain balance across the Availability Zones in your cluster using the following logic:

• Sort the container instances by the largest 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 two, container instances in either zone B or C are considered optimal for termination.
• Stop the task on a container instance in an optimal Availability Zone (based on the previous steps), favoring container instances with the largest number of running tasks for this service.
Synopsis

# Creating a Request

Arguments

 :: Text usService -> UpdateService

Creates a value of UpdateService with the minimum fields required to make a request.

Use one of the following lenses to modify other fields as desired:

• usCluster - The short name or full Amazon Resource Name (ARN) of the cluster that your service is running on. If you do not specify a cluster, the default cluster is assumed.
• usPlatformVersion - The platform version you want to update your service to run.
• usDesiredCount - The number of instantiations of the task to place and keep running in your service.
• usForceNewDeployment - Whether to force a new deployment of the service. Deployments are not forced by default. You can use this option to trigger a new deployment with no service definition changes. For example, you can update a service's tasks to use a newer Docker image with the same image/tag combination (my_image:latest ) or to roll Fargate tasks onto a newer platform version.
• usTaskDefinition - The family and revision (family:revision ) or full ARN of the task definition to run in your service. If a revision is not specified, the latest ACTIVE revision is used. If you modify the task definition with UpdateService , Amazon ECS spawns a task with the new version of the task definition and then stops an old task after the new version is running.
• usHealthCheckGracePeriodSeconds - The period of time, in seconds, that the Amazon ECS service scheduler should ignore unhealthy Elastic Load Balancing target health checks after a task has first started. This is only valid if your service is configured to use a load balancer. If your service's tasks take a while to start and respond to Elastic Load Balancing health checks, you can specify a health check grace period of up to 1,800 seconds during which the ECS service scheduler ignores the Elastic Load Balancing health check status. This grace period can prevent the ECS service scheduler from marking tasks as unhealthy and stopping them before they have time to come up.
• usNetworkConfiguration - The network configuration for the service. This parameter is required for task definitions that use the awsvpc network mode to receive their own elastic network interface, and it is not supported for other network modes. For more information, see Task Networking in the Amazon Elastic Container Service Developer Guide .
• usDeploymentConfiguration - Optional deployment parameters that control how many tasks run during the deployment and the ordering of stopping and starting tasks.
• usService - The name of the service to update.

See: updateService smart constructor.

Instances

# Request Lenses

The short name or full Amazon Resource Name (ARN) of the cluster that your service is running on. If you do not specify a cluster, the default cluster is assumed.

Whether to force a new deployment of the service. Deployments are not forced by default. You can use this option to trigger a new deployment with no service definition changes. For example, you can update a service's tasks to use a newer Docker image with the same image/tag combination (my_image:latest ) or to roll Fargate tasks onto a newer platform version.

The family and revision (family:revision ) or full ARN of the task definition to run in your service. If a revision is not specified, the latest ACTIVE revision is used. If you modify the task definition with UpdateService , Amazon ECS spawns a task with the new version of the task definition and then stops an old task after the new version is running.

The period of time, in seconds, that the Amazon ECS service scheduler should ignore unhealthy Elastic Load Balancing target health checks after a task has first started. This is only valid if your service is configured to use a load balancer. If your service's tasks take a while to start and respond to Elastic Load Balancing health checks, you can specify a health check grace period of up to 1,800 seconds during which the ECS service scheduler ignores the Elastic Load Balancing health check status. This grace period can prevent the ECS service scheduler from marking tasks as unhealthy and stopping them before they have time to come up.

The network configuration for the service. This parameter is required for task definitions that use the awsvpc network mode to receive their own elastic network interface, and it is not supported for other network modes. For more information, see Task Networking in the Amazon Elastic Container Service Developer Guide .

Optional deployment parameters that control how many tasks run during the deployment and the ordering of stopping and starting tasks.

The name of the service to update.

# Destructuring the Response

Arguments

 :: Int usrsResponseStatus -> UpdateServiceResponse

Creates a value of UpdateServiceResponse with the minimum fields required to make a request.

Use one of the following lenses to modify other fields as desired:

• usrsService - The full description of your service following the update call.
• usrsResponseStatus - -- | The response status code.

See: updateServiceResponse smart constructor.

Instances