Monitoring Container Status with Load Balancing

An example of monitoring container status with load balancing.

Monitoring container status with load balancing
- Using response codes to monitor status: examples

Monitoring container status with load balancing

In a typical production Akana deployment, the Akana containers are deployed in a cluster and behind a load balancer. The diagram below shows the Network Director behind a load balancer. An application invokes an API hosted on the Network Director through the load balancer.

It is important that the Network Director is functioning, and all the APIs are deployed on it, before any API is invoked. This helps avoid 404 errors being returned to the application/consumer.

This configuration is applicable for any of the Akana containers that are behind a load balancer (for example, Policy Manager, Community Manager, OAuth Provider).

Container health with load balancing: flowchart

To ensure that the Network Director or container is ready to receive requests, the load balancers should be configured to monitor the state of the container using the Load Balancer's system health check URL. This URL returns one of the following:

An HTTP 200 status code if the container ready to process inbound traffic.
An HTTP 503 status code if the container is still coming up.

All the Akana containers that are configured behind a Load Balancer should use the Load Balancer's system health check URL to monitor system health status.

Configure the following container system health check URL in the Load Balancer and check for the following status codes.

Method: GET

URL: http(s)://<container_admin_host>:<container_port>/admin/health/measurables/akana.service.container.readiness?normal-status=200&failure-status=503&warning-status=503&brief=true

HTTP Status Codes:

200—Container is ready, the services/apis are deployed and the container can receive requests.
503—Container is still not ready to receive requests.

Using response codes to monitor status: examples

An example of the request and responses are below.

Request

GET https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness?normal-status=200&failure-status=503&warning-status=503&brief=true HTTP/1.1
Host: 10.1.16.24:8867
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.1.1 (java 1.5)

Response headers: Container is still coming up and is not ready to receive requests

HTTP/1.1 503 Service Unavailable
Date: Tue, 05 Nov 2019 17:13:46 GMT
Content-Type: application/json
Transfer-Encoding: chunked

Response content: Container is still coming up and is not ready to receive requests

{
  "id":"akana.service.container.readiness",
  "name":"Service Container Readiness",
  "path":"akana.service.container.readiness",
  "state":"FAILURE",
  "childCount":7,
  "editable":false,
  "options":{
    "enableAuth":true,
    "links":[
      {
        "rel":"self",
        "href":"https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness/configuration"
      }
    ]
  },
  "links":[
    {
      "rel":"self",
      "href":"https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness"
    },
    {
      "rel":"brief",
      "href":"https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness?brief=true"
    },
    {
      "rel":"children",
      "href":"https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness/children"
    },
    {
      "rel":"options",
      "href":"https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness/configuration"
    }
  ]
}

Response headers: Container is ready to receive traffic

HTTP/1.1 200 OK
Date: Tue, 05 Nov 2019 17:12:20 GMT
Content-Type: application/json
Vary: Accept-Encoding, User-Agent
Transfer-Encoding: chunked

Response content: Container is ready to receive traffic

{
  "id":"akana.service.container.readiness",
  "name":"Service Container Readiness",
  "path":"akana.service.container.readiness",
  "state":"NORMAL",
  "childCount":7,
  "editable":false,
  "options":{
    "enableAuth":true,
    "links":[
      {
        "rel":"self",
        "href":"https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness/configuration"
      }
    ]
  },
  "links":[
    {
      "rel":"self",
      "href":"https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness"
    },
    {
      "rel":"brief",
      "href":"https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness?brief=true"
    },
    {
      "rel":"children",
      "href":"https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness/children"
    },
    {
      "rel":"options",
      "href":"https://10.1.16.24:8867/admin/health/measurables/akana.service.container.readiness/configuration"
    }
  ]
}

Monitoring Container Status with Load Balancing

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