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/ApplicationLoadBalancedFargateService with listener on one port and health check on another fails health check/

ApplicationLoadBalancedFargateService with listener on one port and health check on another fails health check


Hi, I have an ApplicationLoadBalancedFargateService that exposes a service on one port, but the health check runs on another. Unfortunately, the target fails health check and terminates the task. Here's a snippet of my code

    const hostPort = 5701;
    const healthCheckPort = 8080;

    taskDefinition.addContainer(stackPrefix + 'Container', {
      image: ecs.ContainerImage.fromRegistry('hazelcast/hazelcast:3.12.6'),
      environment : {
        'JAVA_OPTS': `-Dhazelcast.local.publicAddress=localhost:${hostPort}`, 
        'PROMETHEUS_PORT': `${healthCheckPort}`},
        portMappings: [{containerPort : hostPort, hostPort: hostPort},{containerPort : healthCheckPort, hostPort: healthCheckPort}],
        logging: ecs.LogDriver.awsLogs({streamPrefix: stackPrefix, logRetention: logs.RetentionDays.ONE_DAY}),

    const loadBalancedFargateService = new ecsPatterns.ApplicationLoadBalancedFargateService(this, stackPrefix + 'Service', {
      publicLoadBalancer : false,
      desiredCount: 1,
      listenerPort: hostPort,
      taskDefinition: taskDefinition,
      securityGroups : [fargateServiceSecurityGroup],
      domainName : env.getPrefixedRoute53(stackName),
      domainZone : env.getDomainZone(),

      path: "/metrics", 
      port: healthCheckPort.toString(),
      timeout: cdk.Duration.seconds(15),  
      interval: cdk.Duration.seconds(30),
      healthyThresholdCount: 2,
      unhealthyThresholdCount: 5,
      healthyHttpCodes: '200-299'

Any suggestions on how I can get this to work? thanks

1 Answers

Hello there,

Looking into your code, a few things I noticed:

  1. For Fagete Service, there is no need to define host port, since the host port and the container port should be the same.

  2. You should use taskImageOptions tp define container port

Here is an example code snippet:

    const service = new EcsPatterns.ApplicationLoadBalancedFargateService(this, 'demoService', {
      cluster: cluster,
      publicLoadBalancer: true,
      memoryLimitMiB: 2048,
      cpu: 512,
      desiredCount: 2,
      serviceName: 'demoService',
      taskImageOptions: {
        containerName: 'web',
        containerPort: 8080,   // Your container or app port
        environment: {
        image: ecs.ContainerImage.fromEcrRepository(repository),
        logDriver: new ecs.AwsLogDriver({
          streamPrefix: props.serviceName,

      path: '/v1/healthcheck',

With above example, ApplicationLoadBalancedFargateService configures health check against container port 8080, but with a different path /v1/healthcheck as per overriding.

answered a month ago

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