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Run Health Checker

This folder contains:

  1. run-health-checker: A Bash script for installing, configuring, and running health-checker.
  2. check-zookeeper: A Bash script for checking health of the ZooKeeper node.
  3. install.sh: A Bash script that installs the run-health-checker script.

Typically, you would run the install.sh script in a Packer template so that you create an Amazon Machine Image (AMI) that comes pre-installed with run-health-checker. Then, by calling run-health-checker in User Data, your server will configure and start health-checker on boot.

run-health-checker​

This script assumes that the following are already installed:

  1. Supervisord: see the install-supervisord module.

The run-health-checker script will use Supervisord to start health-checker.

This script has been tested on the following operating systems:

  • Amazon Linux
  • Ubuntu

There is a good chance it will work on Debian, CentOS, and RHEL as well, but our automated testing for this module does not cover these other distros at the moment.

check-zookeeper​

This script assumes that the following are already installed:

  1. nc: Used to issue srvr command to ZooKeeper.

This script has been tested on the following operating systems:

  • Amazon Linux
  • Ubuntu

There is a good chance it will work on Debian, CentOS, and RHEL as well, but our automated testing for this module does not cover these other distros at the moment.

Quick start​

The easiest way to install the run-health-checker script is with the Gruntwork Installer:

gruntwork-install \
  --module-name "run-health-checker" \
  --repo "https://github.com/gruntwork-io/terraform-aws-zookeeper" \
  --tag "v0.4.11"

This will download and install health-checker itself, as well as the run-health-checker and check-zookeeper scripts. Later, when you run the run-health-checker script, you'll configure health-checker to run as a service.

We recommend running this module as part of a Packer template to create an Amazon Machine Image (AMI) (see the zookeeper-ami example for a fully-working example).

Install command line arguments​

When you run gruntwork-install to install run-health-checker, gruntwork-install downloads the appropriate version of the run-health-checker module from GitHub and runs the install.sh script in the folder. The install.sh script accepts the following arguments, all optional:

  • --install-dir: The directory where the run-health-checker files should be installed. Default: /opt/health-checker.
  • --user: The user who will be set as the owner of --install-dir. Default: health_checker.
  • --version: The version of health-checker to install. May be specified as a Tag Constraint Expression

If you're using gruntwork-install to run this module, you can pass these arguments using --module-param arguments. Example:

gruntwork-install \
  --module-name "run-health-checker" \
  --repo "https://github.com/gruntwork-io/terraform-aws-zookeeper" \
  --tag "v0.4.11" \
  --module-param "install-dir=/opt/health-checker"

run-health-checker command line arguments​

When you run the run-health-checker script itself, you must provide the following arguments:

  • --tcp-port: The port number on which a TCP connection will be attempted by health-checker. Specify one or more times.

For example, to configure health-checker to run as a service using Supervisord that listens on its default port of 5000 for inbound HTTP requests and which uses all inbound requests to trigger an attempt to open a TCP connection to port 8000 and run a custom health check script with a timeout of 5 seconds, you can use:

run-health-checker \
  --tcp-port 8080 \
  --script "/opt/health-checker/check-zookeeper --zkport 2181" \
  --script-timeout 5

To see the other arguments that run-health-checker accepts, run run-health-checker with the --help flag or view the source code.