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An object representing a container health check. Health check parameters that are specified in a container definition override any Docker health checks that exist in the container image (such as those specified in a parent image or from the image's Dockerfile).

You can view the health status of both individual containers and a task with the DescribeTasks API operation or when viewing the task details in the console.

The following describes the possible healthStatus values for a container:

• HEALTHY-The container health check has passed successfully.
• UNHEALTHY-The container health check has failed.
• UNKNOWN-The container health check is being evaluated or there is no container health check defined.

The following describes the possible healthStatus values for a task. The container health check status of nonessential containers do not have an effect on the health status of a task.

• HEALTHY-All essential containers within the task have passed their health checks.
• UNHEALTHY-One or more essential containers have failed their health check.
• UNKNOWN-The essential containers within the task are still having their health checks evaluated or there are no container health checks defined.

If a task is run manually, and not as part of a service, the task will continue its lifecycle regardless of its health status. For tasks that are part of a service, if the task reports as unhealthy then the task will be stopped and the service scheduler will replace it.

The following are notes about container health check support:

• Container health checks require version 1.17.0 or greater of the Amazon ECS container agent. For more information, see Updating the Amazon ECS Container Agent.
• Container health checks are supported for Fargate tasks if you are using platform version 1.1.0 or greater. For more information, see Fargate Platform Versions.
• Container health checks are not supported for tasks that are part of a service that is configured to use a Classic Load Balancer.

See: newHealthCheck smart constructor.

Create a value of HealthCheck with all optional fields omitted.

Use generic-lens or optics to modify other optional fields.

The following record fields are available, with the corresponding lenses provided for backwards compatibility:

$sel:startPeriod:HealthCheck', healthCheck_startPeriod - The optional grace period within which to provide containers time to bootstrap before failed health checks count towards the maximum number of retries. You may specify between 0 and 300 seconds. The startPeriod is disabled by default.

If a health check succeeds within the startPeriod, then the container is considered healthy and any subsequent failures count toward the maximum number of retries.

$sel:retries:HealthCheck', healthCheck_retries - The number of times to retry a failed health check before the container is considered unhealthy. You may specify between 1 and 10 retries. The default value is 3.

$sel:interval:HealthCheck', healthCheck_interval - The time period in seconds between each health check execution. You may specify between 5 and 300 seconds. The default value is 30 seconds.

$sel:timeout:HealthCheck', healthCheck_timeout - The time period in seconds to wait for a health check to succeed before it is considered a failure. You may specify between 2 and 60 seconds. The default value is 5.

$sel:command:HealthCheck', healthCheck_command - A string array representing the command that the container runs to determine if it is healthy. The string array must start with CMD to execute the command arguments directly, or CMD-SHELL to run the command with the container's default shell.

When you use the Amazon Web Services Management Console JSON panel, the Command Line Interface, or the APIs, you should enclose the list of commands in brackets, as shown below.

[ "CMD-SHELL", "curl -f http://localhost/ || exit 1" ]

You do not need to include the brackets when you use the Amazon Web Services Management Consoleas shown below.

 "CMD-SHELL", "curl -f http://localhost/ || exit 1"

An exit code of 0 indicates success, and non-zero exit code indicates failure. For more information, see HealthCheck in the Create a container section of the Docker Remote API.

The optional grace period within which to provide containers time to bootstrap before failed health checks count towards the maximum number of retries. You may specify between 0 and 300 seconds. The startPeriod is disabled by default.

If a health check succeeds within the startPeriod, then the container is considered healthy and any subsequent failures count toward the maximum number of retries.

The number of times to retry a failed health check before the container is considered unhealthy. You may specify between 1 and 10 retries. The default value is 3.

The time period in seconds between each health check execution. You may specify between 5 and 300 seconds. The default value is 30 seconds.

The time period in seconds to wait for a health check to succeed before it is considered a failure. You may specify between 2 and 60 seconds. The default value is 5.

A string array representing the command that the container runs to determine if it is healthy. The string array must start with CMD to execute the command arguments directly, or CMD-SHELL to run the command with the container's default shell.

When you use the Amazon Web Services Management Console JSON panel, the Command Line Interface, or the APIs, you should enclose the list of commands in brackets, as shown below.

[ "CMD-SHELL", "curl -f http://localhost/ || exit 1" ]

You do not need to include the brackets when you use the Amazon Web Services Management Consoleas shown below.

 "CMD-SHELL", "curl -f http://localhost/ || exit 1"

An exit code of 0 indicates success, and non-zero exit code indicates failure. For more information, see HealthCheck in the Create a container section of the Docker Remote API.