A distributed protocol tester.
Ian Chilton
Ian Chilton Merge branch '23-fallback-ssl-timeout' into 'master'
Resolve "The fallback SSL certificate check occasionally hogs a dequeue thread (potentially forever)"

Closes #23

See merge request open-source/custodian!16
Latest commit cfc6baf Jul 11, 2018



Custodian is a distributed protocol-tester written in portable Ruby, which can easily scale to covering the needs of a large network.

Here are some quick-links:

About Custodian

Custodian is a simple, scalable, and reliable protocol-tester that allows a number of services to be tested across a network.

The core design is based upon a work queue, which is manipulated by two main tools:

  • custodian-enqueue

    • A parser that reads a list of hosts and tests to apply. These tests are broken down into individual jobs, serialized and stored in a central queue.
  • custodian-dequeue

    • A tool that pulls jobs from the queue, executing them in turn, and raises/clears alerts based upon the result of the test.

Custodian uses class-factories to ensure that protocol tests, and notification objects, are only loosely tied to the core. This is done so that custodian may be extended or adapted more easily to your environment.


The software is configured by the main configuration file located at:


This file contains the alerting mechanism to use, the IP:port of the queue the two scripts mentioned above use, and similar static things.

Each of the available configuration options has a sensible default which is documented in that same file.


The software is written in Ruby and has successfully been deployed in production under:

  • Ruby 1.8
  • Ruby 1.9.x
  • Ruby 2.1.x

The software has not yet been tested upon JRuby, or similar.

Dependencies, beyond ruby, are limited to the following gems:

  • For HTTP/HTTPS testing: curb
  • For communication with the queue: redis