Arborist is a monitoring toolkit that follows the UNIX philosophy
of small parts and loose coupling for stability, reliability, and
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
It tries to provide sane defaults, while allowing fine grained settings
per resource node. Both Windows and UCD-SNMP systems are supported.
* Ruby 2.3 or better
$ gem install arborist-snmp
Global configuration overrides can be added to the Arborist config file,
under the `snmp` key.
The defaults are as follows:
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
* **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.
* **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.
* **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.
* **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.
* **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.
In the simplest form, using default behaviors and settings, here's an
example Monitor configuration:
Arborist::Monitor 'cpu load check', :cpu do
match type: 'resource', category: 'cpu'
exec( Arborist::Monitor::SNMP::CPU )
Arborist::Monitor 'partition capacity', :disk do
match type: 'resource', category: 'disk'
exec( Arborist::Monitor::SNMP::Disk )
Arborist::Monitor 'process checks', :proc do
match type: 'resource', category: 'process'
exec( Arborist::Monitor::SNMP::Process )
Arborist::Monitor 'memory', :memory do
match type: 'resource', category: 'memory'
exec( Arborist::Monitor::SNMP::Memory )
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
match type: 'service', protocol: 'udp'
exec( Arborist::Monitor::Socket::UDP )
And a default node declaration:
Arborist::Host 'example' do
description 'An example host'
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.
Arborist::Host 'example' do
description 'An example host'
service 'snmp', protocol: 'udp'
resource 'cpu', description: 'machine cpu load' do
resource 'memory', description: 'machine ram and swap' do
config physical_warn_at: 95, swap_warn_at: 10
resource 'disk', description: 'partition capacity' do
'/tmp' => 50,
'/var' => 80
resource 'process' do
config check: 'important --production'
Copyright (c) 2016-2018 Michael Granger and Mahlon E. Smith
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