monit

Table of Contents

1. Description
2. Setup - The basics of getting started with monit
   • What monit affects
   • Setup requirements
   • Beginning with monit
3. Usage - Configuration options and additional functionality
4. Reference - An under-the-hood peek at what the module is doing and how
5. Limitations - OS compatibility, etc.
6. Development - Guide for contributing to the module

Description

Performs installation and configuration of Monit service, along with fine grained definition of checks.

All check types provided by Monit are supported. Namely: directory, fifo, file, filesystem, host, process, program, and system.

In adition to primitive types, a compound check type is provided: service. It is a set of primitives to check a service's init script, binary and process.

Setup

Beginning with monit

include '::monit' is enough to get you up and running. It will configure the basis of monit, with HTTP server listening at localhost:2812 and a system check for LOADAVG, CPU, MEMORY and FILESYSTEM at /.

To pass in parameters and override default configuration:

class { '::monit':
  check_interval    => 60,
  check_start_delay => 120,
  mailserver        => 'localhost',
  eventqueue        => true,
  alerts            => ['root@localhost', 'sla1@example.com only on { timeout, nonexist }'],
  httpserver        => true,
  httpserver_allow  => ['admin:secret'],
}

Usage

All parameters for the monit module are contained within the main ::monit class, so for any function of the module, set the options you want. See the common usages below for examples.

Check types are implemented by defined types, named after monit::check::TYPE. All check types have several configuration options in common (ex: group, priority, alerts, dependencies, etc.), along with the check specific options.

On the other hand, monit::check defined type is a facade for all check types. It works as a single entry point to declare any type of check in the same way. Common configuration options are parameters of the defined type, and check specific options are passed through a hash in the config parameter.

So there're several entry points to declare your own checks:

• Create an instance of the specific defined type for the given check (ex: monit::check::TYPE)
• Create an instance of the generic monit::check defined type, and pass in the details of the check
• Pass in a hash of checks to ::monit class. This enables providing the checks from Hiera, with your preferred merge strategy

Install and enable monit

include '::monit'

Customize the system check

class { '::monit':
  system_cpu_wait       => '40%',
  system_memory         => '84%',
  system_loadavg_1min   => 14.0,
  system_fs_space_usage => '88%',
  system_fs             => ['/', '/mnt/backups'],
}

Declare a check by instantiating the check's defined type

include ::monit

monit::check::filesystem { 'somefs':
  paths => ['/mount/somefs',],
  tests => [
    {'type' => 'fsflags'},
    {'type' => 'permission', 'value' => '0755'},
    {'type' => 'space', 'operator' => '>', 'value' => '80%'},
  ]
}

Declare a check by instantiating the generic check defined type

include ::monit

# Add a check for ntp process.
monit::check { 'ntp':
  type              => 'process',
  config            => {
    'pidfile'       => '/var/run/ntpd.pid',
    'program_start' => '/etc/init.d/ntp start',
    'program_stop'  => '/etc/init.d/ntp stop',
  },
  tests             => [
    {
      'type'     => 'connection',
      'host'     => '127.0.0.1',
      'port'     => '123',
      'protocol' => 'ntp',
      'action'   => 'restart',
    },
  ],
}

Provide the monit class with a check for ssh service

include::monit

class { '::monit':
  checks => {
    'sshd' => {
      'type'    => 'service',
      'config' => {
        'pidfile' => '/var/run/sshd.pid',
      },
      'tests'  => [
        {
          'type'     => 'connection',
          'host'     => '127.0.0.1',
          'port'     => '22',
          'protocol' => 'ssh',
          'action'   => 'restart',
        },
      ],
    },
  }
}

Provide full module config and checks from Hiera

# Main monitrc configuration options.
monit::check_interval: '60'
monit::check_start_delay: '120'
monit::mailserver: 'localhost'
monit::eventqueue: true
monit::alerts:
  - 'root@localhost'
  - 'sla1@example.com only on { timeout, nonexist }'
monit::httpserver: true
monit::httpserver_allow:
  - 'admin:secret'

# Tweak system check.
monit::system_fs: ['/', '/mnt/backups']

# Add some checks.
monit::checks:

  somefs:
    type: filesystem
    config:
      paths:
        - /
        - /mount/somefs
    tests:
      - type: fsflags
      - type: permission
        value: '0755'
      - type: space
        operator: '>'
        value: 80%

  sshd:
    type: process
    config:
      pidfile: /var/run/sshd.pid
      program_start: /etc/init.d/sshd start
      program_stop: /etc/init.d/sshd stop
    tests:
      - type: connection
        host: 127.0.0.1
        port: 22
        protocol: ssh
        action: restart

  php5-fpm:
    type: process
    config:
      pidfile: /var/run/php5-fpm.pid
      program_start: /etc/init.d/php5-fpm start
      program_stop: /etc/init.d/php5-fpm stop
    tests:
      - type: connection
        host: 127.0.0.1
        port: 9000
        socket_type: TCP
        protocol: GENERIC
        protocol_test:
          - send: '"\0x01\0x09\0x00\0x00\0x00\0x00\0x08\0x00\0x00\0x00\0x00\0x00\0x00\0x00\0x00\0x00"'
            expect: '"\0x01\0x0A"'
        action: restart

  ntp:
    type: process
    config:
      pidfile: /var/run/ntpd.pid
      program_start: /etc/init.d/ntpd start
      program_stop: /etc/init.d/ntpd stop
    tests:
      - type: connection
        host: 127.0.0.1
        socket_type: udp
        port: 123
        protocol: ntp
        action: restart

  varnish:
    type: process
    config:
      pidfile: /var/run/varnish.pid
      program_start: /etc/init.d/varnish start
      program_stop: /etc/init.d/varnish stop
    tests:
      - type: connection
        host: 127.0.0.1
        port: 8080
        protocol: http
        protocol_test:
          request: /health.varnish
      - type: cpu(user)
        operator: '>'
        value: 60%
        tolerance:
          cycles: 2
      - type: children
        operator: '>'
        value: 150

  httpd:
    type: service
    config:
      pidfile: /var/run/httpd/httpd.pid
      binary: /usr/sbin/httpd
    tests:
      - type: connection
        host: 127.0.0.1
        port: 80
        protocol: http

# Notice: Param 'HOSTHEADER' changed to 'HTTP HEADERS' in monit 5.9
# see https://mmonit.com/monit/changes/
  http_headers:
    type: host
    config:
      address: 127.0.0.1
    tests:
      - type: connection
        host: 127.0.0.1
        port: 80
        protocol: http
        protocol_test:
          request: /
          status: 200
          http headers: '[host: www.example.com]'

  custom-script:
    type: program
    config:
      path: /path/to/custom/pingcheck.sh
    tests:
      - type: status
        operator: '!='
        value: 0
        tolerance:
          cycles: 2
        action: exec
        exec: sudo /sbin/reboot
        # uid, git and repeat_every are optional.
        uid: root
        gid: root
        repeat_every: 1

  reboot:
    type: system
    tests:
      - type: uptime
        operator: '<'
        value: '3 MINUTES'

There's a bunch of examples for configuring real services across Debian and RedHat families in sbitio/ducktape module. Please refer to manifests/*/external/monit.pp files.

Reference

See Puppet Strings doc at doc/index.html

Limitations

This module requires Puppet 4.x or above, and is compatible with the following OSes/versions:

• FreeBSD
• Debian 7, 8, 9, 10, 11
• RedHat/CentOS 7, 8
• Ubuntu 12.04, 14.04, 16.04

For Puppet 3 or older versions of Debian, please use 1.x.x releases.

Development

Development happens on GitHub.

Please log issues for any bug report, feature or support request.

Pull requests are welcome.

License

MIT License, see LICENSE file

Contact

Use contact form on http://sbit.io