Copyright | (c) 2013-2016 Brendan Hay |
---|---|
License | Mozilla Public License, v. 2.0. |
Maintainer | Brendan Hay <brendan.g.hay@gmail.com> |
Stability | auto-generated |
Portability | non-portable (GHC extensions) |
Safe Haskell | None |
Language | Haskell2010 |
Runs and maintains a desired number of tasks from a specified task definition. If the number of tasks running in a service drops below desiredCount
, Amazon ECS spawns another instantiation of the task in the specified cluster. To update an existing service, see UpdateService.
In addition to maintaining the desired count of tasks in your service, you can optionally run your service behind a load balancer. The load balancer distributes traffic across the tasks that are associated with the service. For more information, see Service Load Balancing in the Amazon EC2 Container Service Developer Guide.
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 minimumHealthyPercent
and maximumPercent
parameters to determine the deployment strategy.
If the minimumHealthyPercent
is below 100%, the scheduler can ignore the desiredCount
temporarily during a deployment. For example, if your service has a desiredCount
of four tasks, a minimumHealthyPercent
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 RUNNING
state 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.
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 your service has a desiredCount
of four tasks, a 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.
- createService :: Text -> Text -> Int -> CreateService
- data CreateService
- cCluster :: Lens' CreateService (Maybe Text)
- cClientToken :: Lens' CreateService (Maybe Text)
- cLoadBalancers :: Lens' CreateService [LoadBalancer]
- cRole :: Lens' CreateService (Maybe Text)
- cDeploymentConfiguration :: Lens' CreateService (Maybe DeploymentConfiguration)
- cServiceName :: Lens' CreateService Text
- cTaskDefinition :: Lens' CreateService Text
- cDesiredCount :: Lens' CreateService Int
- createServiceResponse :: Int -> CreateServiceResponse
- data CreateServiceResponse
- csrsService :: Lens' CreateServiceResponse (Maybe ContainerService)
- csrsResponseStatus :: Lens' CreateServiceResponse Int
Creating a Request
Creates a value of CreateService
with the minimum fields required to make a request.
Use one of the following lenses to modify other fields as desired:
data CreateService Source #
See: createService
smart constructor.
Request Lenses
cCluster :: Lens' CreateService (Maybe Text) Source #
The short name or full Amazon Resource Name (ARN) of the cluster on which to run your service. If you do not specify a cluster, the default cluster is assumed.
cClientToken :: Lens' CreateService (Maybe Text) Source #
Unique, case-sensitive identifier you provide to ensure the idempotency of the request. Up to 32 ASCII characters are allowed.
cLoadBalancers :: Lens' CreateService [LoadBalancer] Source #
A load balancer object representing the load balancer to use with your service. Currently, you are limited to one load balancer per service. After you create a service, the load balancer name, container name, and container port specified in the service definition are immutable.
For Elastic Load Balancing Classic load balancers, this object must contain the load balancer name, the container name (as it appears in a container definition), and the container port to access from the load balancer. When a task from this service is placed on a container instance, the container instance is registered with the load balancer specified here.
For Elastic Load Balancing Application load balancers, this object must contain the load balancer target group ARN, the container name (as it appears in a container definition), and the container port to access from the load balancer. When a task from this service is placed on a container instance, the container instance and port combination is registered as a target in the target group specified here.
cRole :: Lens' CreateService (Maybe Text) Source #
The name or full Amazon Resource Name (ARN) of the IAM role that allows Amazon ECS to make calls to your load balancer on your behalf. This parameter is required if you are using a load balancer with your service. If you specify the role
parameter, you must also specify a load balancer object with the loadBalancers
parameter.
If your specified role has a path other than \/
, then you must either specify the full role ARN (this is recommended) or prefix the role name with the path. For example, if a role with the name bar
has a path of '\/foo\/' then you would specify '\/foo\/bar' as the role name. For more information, see Friendly Names and Paths in the IAM User Guide.
cDeploymentConfiguration :: Lens' CreateService (Maybe DeploymentConfiguration) Source #
Optional deployment parameters that control how many tasks run during the deployment and the ordering of stopping and starting tasks.
cServiceName :: Lens' CreateService Text Source #
The name of your service. Up to 255 letters (uppercase and lowercase), numbers, hyphens, and underscores are allowed. Service names must be unique within a cluster, but you can have similarly named services in multiple clusters within a region or across multiple regions.
cTaskDefinition :: Lens' CreateService Text Source #
The family
and revision
('family:revision') or full Amazon Resource Name (ARN) of the task definition to run in your service. If a revision
is not specified, the latest ACTIVE
revision is used.
cDesiredCount :: Lens' CreateService Int Source #
The number of instantiations of the specified task definition to place and keep running on your cluster.
Destructuring the Response
createServiceResponse Source #
Creates a value of CreateServiceResponse
with the minimum fields required to make a request.
Use one of the following lenses to modify other fields as desired:
data CreateServiceResponse Source #
See: createServiceResponse
smart constructor.
Response Lenses
csrsService :: Lens' CreateServiceResponse (Maybe ContainerService) Source #
The full description of your service following the create call.
csrsResponseStatus :: Lens' CreateServiceResponse Int Source #
The response status code.