1 Introduction

This concept gives an overview of IOM server health checks and how they can be used within an HA installation of IOM. The document is mainly addressed to application administration.

1.1 Glossary

1.2 References

• Guide - Intershop Order Management - Technical Overview

• Overview - IOM Setup

• Overview - IOM Watchdog
• Overview - IOM REST API

2 Health Status of Application Servers

An application server is one single application server within a cluster of multiple application servers.

The health status of an application server reflects whether the server is able to adequately fulfill all tasks it is responsible for.

For Intershop Order Management, the status can be requested using the REST API. Additionally, the result will be persisted to the database as part of the cluster status.

The health check includes basic connecting to the database. Further checks, e.g., access to shared file-system is possible.

2.1 Application Server Monitoring

The main purpose of a health status support is to enable server monitoring applications to manage the application cluster, i. e., not to host unhealthy/broken servers and/or to trigger the repair/restart of unhealthy/broken servers.

Especially in case of HA health checks are required to always ensure a running application.

The IOM provides Watchdog to monitor the application server health statuses and to control the application server based on this information.

3 Cluster Status

The cluster status reflects the general health status of each application server of a server cluster. Basically it can be used to give a quick overview of the healthiness of the server cluster.

The cluster status can be requested using REST API which returns the persisted results from the last health status check of each application server.

4 REST

The REST response for the application server health status will return a status code that reflects the health status and can be used by the server monitoring application.

An additional payload gives detailed information on the processed checks and their results.

{
  "services": [
    {
      "name": "ftp-media-host",
      "checked": false,
      "statusCode": 204,
      "description": "The service was configured not to be checked."
    },
    {
      "name": "ftp-pdf-host",
      "checked": true,
      "statusCode": 200,
      "description": "OK"
    },
    {
      "name": "database",
      "checked": true,
      "statusCode": 200,
      "description": "OK"
    }
  ],
  "serverId": "jdevoms06.rnd.j.intershop.de_0.0.0.0",
  "serverType": "frontend",
  "statusCode": 200,
  "description": "OK",
  "lastCheckEpoch": 1484838994495,
  "lastSuccessfulCheckEpoch": 1484838994495,
  "lastCheck": "2017-01-19 16:16:34:495 +0100",
  "lastSuccessfulCheck": "2017-01-19 16:16:34:495 +0100"
}

5 Further Information

5.1 Deployment

To offer the health check for an IOM application server, the artifact oms.monitoring must be deployed.

5.2 Configuration of Checked Services

The following list describes the current checks that are done by a health check.

Also see Guide - Setup Intershop Order Management 2.2 or later, see Overview - IOM Setup, for cluster properties.

5.3 Triggering Health Checks

The following list describes how the check works for different versions.

Also see Guide - Setup Intershop Order Management 2.2 or later, see Overview - IOM Setup, for cluster properties.

5.4 Expandability

The health check can be extended within HealthServiceBean.java of artifact oms.monitoring by adding a new check.