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layout: default
navsection: admin
title: Health checks
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{% comment %}
Copyright (C) The Arvados Authors. All rights reserved.

SPDX-License-Identifier: CC-BY-SA-3.0
{% endcomment %}

Health check endpoints are found at @/_health/ping@ on many Arvados services.  The purpose of the health check is to offer a simple method of determining if a service can be reached and allow the service to self-report any problems, suitable for integrating into operational alert systems.

To access health check endpoints, services must be configured with a "management token":management-token.html .

Health check endpoints return a JSON object with the field @health@.  This has a value of either @OK@ or @ERROR@.  On error, it may also include a  field @error@ with additional information.  Examples:

<pre>
{
  "health": "OK"
}
</pre>

<pre>
{
  "health": "ERROR"
  "error": "Inverted polarity in the warp core"
}
</pre>

h2. Healthcheck aggregator

The service @arvados-health@ performs health checks on all configured services and returns a single value of @OK@ or @ERROR@ for the entire cluster.  It exposes the endpoint @/_health/all@ .

The healthcheck aggregator uses the @NodeProfile@ section of the cluster-wide @arvados.yml@ configuration file.  Here is an example.

<pre>
Cluster:
  # The cluster uuid prefix
  zzzzz:
    ManagementToken: xyzzy
    NodeProfile:
      # For each node, the profile name corresponds to a
      # locally-resolvable hostname, and describes which Arvados
      # services are available on that machine.
      api:
        arvados-controller:
          Listen: :8000
        arvados-api-server:
          Listen: :8001
      manage:
	arvados-node-manager:
	  Listen: :8002
      workbench:
	arvados-workbench:
	  Listen: :8003
	arvados-ws:
	  Listen: :8004
      keep:
	keep-web:
	  Listen: :8005
	keepproxy:
	  Listen: :8006
	keep-balance:
	  Listen: :9005
      keep0:
        keepstore:
	  Listen: :25107
      keep1:
        keepstore:
	  Listen: :25107
</pre>