software.amazon.awssdk.services.ecs.model

Class HealthCheck

java.lang.Object

software.amazon.awssdk.services.ecs.model.HealthCheck

All Implemented Interfaces:

Serializable, SdkPojo, ToCopyableBuilder<HealthCheck.Builder,HealthCheck>

@Generated(value="software.amazon.awssdk:codegen")
public final class HealthCheck
extends Object
implements SdkPojo, Serializable, ToCopyableBuilder<HealthCheck.Builder,HealthCheck>

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). This configuration maps to the HEALTHCHECK parameter of docker run.

The Amazon ECS container agent only monitors and reports on the health checks specified in the task definition. Amazon ECS does not monitor Docker health checks that are embedded in a container image and not specified in the container definition. Health check parameters that are specified in a container definition override any Docker health checks that exist in the container image.

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 health check is designed to make sure that your containers survive agent restarts, upgrades, or temporary unavailability.

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, there's no container health check defined, or Amazon ECS doesn't have the health status of the container.

The following describes the possible healthStatus values based on the container health checker status of essential containers in the task with the following priority order (high to low):

• UNHEALTHY-One or more essential containers have failed their health check.

• UNKNOWN-Any essential container running within the task is in an UNKNOWN state and no other essential containers have an UNHEALTHY state.

• HEALTHY-All essential containers within the task have passed their health checks.

Consider the following task health example with 2 containers.

• If Container1 is UNHEALTHY and Container2 is UNKNOWN, the task health is UNHEALTHY.

• If Container1 is UNHEALTHY and Container2 is HEALTHY, the task health is UNHEALTHY.

• If Container1 is HEALTHY and Container2 is UNKNOWN, the task health is UNKNOWN .

• If Container1 is HEALTHY and Container2 is HEALTHY, the task health is HEALTHY .

Consider the following task health example with 3 containers.

• If Container1 is UNHEALTHY and Container2 is UNKNOWN, and Container3 is UNKNOWN, the task health is UNHEALTHY.

• If Container1 is UNHEALTHY and Container2 is UNKNOWN, and Container3 is HEALTHY, the task health is UNHEALTHY.

• If Container1 is UNHEALTHY and Container2 is HEALTHY, and Container3 is HEALTHY, the task health is UNHEALTHY.

• If Container1 is HEALTHY and Container2 is UNKNOWN, and Container3 is HEALTHY, the task health is UNKNOWN.

• If Container1 is HEALTHY and Container2 is UNKNOWN, and Container3 is UNKNOWN, the task health is UNKNOWN.

• If Container1 is HEALTHY and Container2 is HEALTHY, and Container3 is HEALTHY, the task health is HEALTHY.

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:

• When the Amazon ECS agent cannot connect to the Amazon ECS service, the service reports the container as UNHEALTHY.

• The health check statuses are the "last heard from" response from the Amazon ECS agent. There are no assumptions made about the status of the container health checks.

• 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're using platform version 1.1.0 or greater. For more information, see Fargate platform versions.

• Container health checks aren't supported for tasks that are part of a service that's configured to use a Classic Load Balancer.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	HealthCheck.Builder

Method Summary

Modifier and Type	Method and Description
static HealthCheck.Builder	builder()
List<String>	command() A string array representing the command that the container runs to determine if it is healthy.
boolean	equals(Object obj)
boolean	equalsBySdkFields(Object obj)
<T> Optional<T>	getValueForField(String fieldName, Class<T> clazz)
boolean	hasCommand() For responses, this returns true if the service returned a value for the Command property.
int	hashCode()
Integer	interval() The time period in seconds between each health check execution.
Integer	retries() The number of times to retry a failed health check before the container is considered unhealthy.
List<SdkField<?>>	sdkFields()
static Class<? extends HealthCheck.Builder>	serializableBuilderClass()
Integer	startPeriod() The optional grace period to provide containers time to bootstrap before failed health checks count towards the maximum number of retries.
Integer	timeout() The time period in seconds to wait for a health check to succeed before it is considered a failure.
HealthCheck.Builder	toBuilder()
String	toString() Returns a string representation of this object.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface software.amazon.awssdk.utils.builder.ToCopyableBuilder

copy

Method Detail

hasCommand

public final boolean hasCommand()

For responses, this returns true if the service returned a value for the Command property. This DOES NOT check that the value is non-empty (for which, you should check the isEmpty() method on the property). This is useful because the SDK will never return a null collection or map, but you may need to differentiate between the service returning nothing (or null) and the service returning an empty collection or map. For requests, this returns true if a value for the property was specified in the request builder, and false if a value was not specified.

command

public final List<String> 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 run 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, enclose the list of commands in double quotes and brackets.

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

You don't include the double quotes and brackets when you use the Amazon Web Services Management Console.

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.

Attempts to modify the collection returned by this method will result in an UnsupportedOperationException.

This method will never return null. If you would like to know whether the service returned this field (so that you can differentiate between null and empty), you can use the hasCommand() method.

Returns:

A string array representing the command that the container runs to determine if it is healthy. The string array must start with CMD to run 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, enclose the list of commands in double quotes and brackets.

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

You don't include the double quotes and brackets when you use the Amazon Web Services Management Console.

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.

interval

public final Integer 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.

Returns:

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

timeout

public final Integer 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.

Returns:

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.

retries

public final Integer 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.

Returns:

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.

startPeriod

public final Integer startPeriod()

The optional grace period to provide containers time to bootstrap before failed health checks count towards the maximum number of retries. You can specify between 0 and 300 seconds. By default, the startPeriod is off.

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.

Returns:

The optional grace period to provide containers time to bootstrap before failed health checks count towards the maximum number of retries. You can specify between 0 and 300 seconds. By default, the startPeriod is off.

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.

toBuilder

public HealthCheck.Builder toBuilder()

Specified by:

toBuilder in interface ToCopyableBuilder<HealthCheck.Builder,HealthCheck>

builder

public static HealthCheck.Builder builder()

serializableBuilderClass

public static Class<? extends HealthCheck.Builder> serializableBuilderClass()

hashCode

public final int hashCode()

Overrides:

hashCode in class Object

equals

public final boolean equals(Object obj)

Overrides:

equals in class Object

equalsBySdkFields

public final boolean equalsBySdkFields(Object obj)

Specified by:

equalsBySdkFields in interface SdkPojo

toString

public final String toString()

Returns a string representation of this object. This is useful for testing and debugging. Sensitive data will be redacted from this string using a placeholder value.

Overrides:

toString in class Object

getValueForField

public final <T> Optional<T> getValueForField(String fieldName,
                                              Class<T> clazz)

sdkFields

public final List<SdkField<?>> sdkFields()

Specified by:

sdkFields in interface SdkPojo