Arborist-SNMP

=============

code

: http://code.martini.nu/Arborist-SNMP

mirrors

: https://github.com/mahlonsmith/Arborist-SNMP

: https://hg.sr.ht/~mahlon/Arborist-SNMP

Description

-----------

Arborist is a monitoring toolkit that follows the UNIX philosophy

of small parts and loose coupling for stability, reliability, and

customizability.

This adds various SNMP support to Arborist's monitoring, specifically

for OIDS involving:

 - Disk space capacity

 - System CPU utilization

 - Memory and swap usage

 - Running process checks

 - UPS battery checks

It tries to provide sane defaults, while allowing fine grained settings

per resource node.  Both Windows and UCD-SNMP systems are supported.

Prerequisites

-------------

  * Ruby 2.4 or better

Installation

------------

    $ gem install arborist-snmp

Configuration

-------------

Global configuration overrides can be added to the Arborist config file,

under the `snmp` key.

The defaults are as follows:

```

arborist:

  snmp:

    timeout: 2

    retries: 1

    community: public

    version: 2c

    port: 161

    batchsize: 25

    cpu:

      warn_at: 80

    disk:

      warn_at: 90

      include: 

      exclude:

      - "^/dev(/.+)?$"

      - "/dev$"

      - "^/net(/.+)?$"

      - "/proc$"

      - "^/run$"

      - "^/sys/"

      - "/sys$"

    processes:

      check: []

    memory:

      physical_warn_at: 

      swap_warn_at: 60

    ups:

      battery:

        capacity_warn_at: 60

        temperature_warn_at: 50

```

The `warn_at` keys imply usage capacity as a percentage. ie:  "Warn me

when a disk mount point is at 90 percent utilization."

### Library Options

  * **timeout**: How long to wait for an SNMP response, in seconds?

  * **retries**: If an error occurs during SNMP communication, try again this many times before giving up.

  * **community**: The SNMP community name for reading data.

  * **version**: The SNMP protocol version.  v1, v2c, and v3 are supported.

  * **port**: The UDP port SNMP is listening on.

  * **batchsize**: How many hosts to gather SNMP data on simultaneously.

### Category Options and Behavior

#### CPU

  * **warn_at**: Set the node to a `warning` state when utilization is at or over this percentage.

Utilization takes into account CPU core counts, and uses the 5 minute

load average to calculate a percentage of current CPU use.

2 properties are set on the node. `cpu` contains the detected CPU count

and current utilization. `load` contains the 1, 5, and 15 minute load

averages of the machine.

#### Disk

  * **warn_at**: Set the node to a `warning` state when disk capacity is at or over this amount.

                 You can also set this to a Hash, keyed on mount name, if you want differing

                 warning values per mount point.  A mount point that is at 100% capacity will

                 be explicity set to `down`, as the resource it represents has been exhausted.

                 This may be helpful in iscsi-root environments.  You can set this to a Hash,

                 keyed on mount name, if you want differing behavior per mount point.

  * **include**: String or Array of Strings.  If present, only matching mount points are

                 considered while performing checks.  These are treated as regular expressions.

  * **exclude**: String or Array of Strings.  If present, matching mount point are removed

                 from evaluation.  These are treated as regular expressions.

A single property "mounts" is set on the node, which is a hash keyed by

mountpoint, with current capacity values.

#### Memory

  * **physical_warn_at**: Set the node to a `warning` state when RAM utilization is at or over this percentage.

  * **swap_warn_at**: Set the node to a `warning` state when swap utilization is at or over this percentage.

Warnings are only set for swap by default, since that is usually a

better indication of an impending problem.

2 properties are set on the node, "memory" and "swap".  Each is a Hash

that contains current usage and remaining available.

#### Processes

  * **check**: String or Array of Strings.  A list of processes to check if running.  These are

               treated as regular expressions, and include process arguments.

If any process in the list is not found in the process table, the

resource is set to a `down` state.

A single property is set on the node, a "counts" key that contains the

current number of running processes.

#### UPS

##### Battery

  * **capacity_warn_at**: Set the node to a `warning` state when the battery capacity is at or below this percentage.

  * **temperature_warn_at**: Set the node to a `warning` state when the battery temperature is at or above this

                             temperature (in Celcius).

This check warns when the UPS is on battery, and reports the UPS' own

estimated time remaining.

A warning state will also be triggered based on battery status - low,

depleted, or unknown.

Examples

--------

In the simplest form, using default behaviors and settings, here's an

example Monitor configuration:

```

require 'arborist/snmp'

Arborist::Monitor 'cpu load check', :cpu do

	every 1.minute

	match type: 'resource', category: 'cpu'

	exec( Arborist::Monitor::SNMP::CPU )

end

Arborist::Monitor 'partition capacity', :disk do

	every 1.minute

	match type: 'resource', category: 'disk'

	exec( Arborist::Monitor::SNMP::Disk )

end

Arborist::Monitor 'process checks', :proc do

	every 1.minute

	match type: 'resource', category: 'process'

	exec( Arborist::Monitor::SNMP::Process )

end

Arborist::Monitor 'memory', :memory do

	every 1.minute

	match type: 'resource', category: 'memory'

	exec( Arborist::Monitor::SNMP::Memory )

end

```

Additionally, if you'd like these SNMP monitors to rely on the SNMP

service itself, you can add a UDP check for that.

```

Arborist::Monitor 'udp service checks', :udp do

	every 30.seconds

	match type: 'service', protocol: 'udp'

	exec( Arborist::Monitor::Socket::UDP )

end

```

And a default node declaration:

```

Arborist::Host 'example' do

	description 'An example host'

	address 'demo.example.com'

	resource 'cpu'

	resource 'memory'

	resource 'disk'

end

```

All configuration can be overridden from the defaults using the `config`

pragma, per node.  Here's a more elaborate example that performs the following:

  * All SNMP monitored resources are quieted if the SNMP service itself is unavailable.

  * Only monitor specific disk partitions, warning at different capacities .

  * Ensure the 'important' processing is running with the '--production' flag.

  * Warns at 95% memory utilization OR 10% swap.

  * Ensure '/' is not a mounted as a read-only filesystem.

-

```

Arborist::Host 'example' do

	description 'An example host'

	address 'demo.example.com'

	service 'snmp', protocol: 'udp'

	resource 'cpu', description: 'machine cpu load' do

		depends_on 'example-snmp'

	end

	resource 'memory', description: 'machine ram and swap' do

		depends_on 'example-snmp'

		config physical_warn_at: 95, swap_warn_at: 10

	end

	resource 'disk', description: 'partition capacity' do

		depends_on 'example-snmp'

		config \

			include: [

				'^/tmp',

				'^/var'

			],

			warn_at: {

				'/tmp' => 50,

				'/var' => 80

			},

			alert_readonly: {

				'/' => true

			}

	end

	resource 'process' do

		depends_on 'example-snmp'

		config check: 'important --production'

	end

end

```

## License

Copyright (c) 2016-2020 Michael Granger and Mahlon E. Smith

All rights reserved.

Redistribution and use in source and binary forms, with or without

modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice,

  this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,

  this list of conditions and the following disclaimer in the documentation

  and/or other materials provided with the distribution.

* Neither the name of the author/s, nor the names of the project's

  contributors may be used to endorse or promote products derived from this

  software without specific prior written permission.

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