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Rules

Rules are defined using a logical language.

The GUI provides a simple way of creating rules.

Creating more complicated rules which may include maths calculations and MySQL queries can be done using macros

Syntax

Rules must consist of at least 3 elements: An Entity, a Condition and a Value. Rules can contain braces and Glues. Entities are provided from Table and Field from the database. For Example: ports.ifOperStatus.

Conditions can be any of:

  • Equals =
  • Not Equals !=
  • In IN
  • Not In NOT IN
  • Begins with LIKE ('...%')
  • Doesn't begin with NOT LIKE ('...%')
  • Contains LIKE ('%...%')
  • Doesn't Contain NOT LIKE ('%...%')
  • Ends with LIKE ('%...')
  • Doesn't end with NOT LIKE ('%...')
  • Between BETWEEN
  • Not Between NOT BETWEEN
  • Is Empty = ''
  • Is Not Empty != '''
  • Is Null IS NULL
  • Is Not Null IS NOT NULL
  • Greater >
  • Greater or Equal >=
  • Less <
  • Less or Equal <=
  • Regex REGEXP

Values can be an entity or any data. If using macros as value you must include the macro name into backticks. i.e. `macros.past_60m`

Note: Regex supports MySQL Regular expressions.

Arithmetics are allowed as well.

Options

Here are some of the other options available when adding an alerting rule:

  • Rule name: The name associated with the rule.
  • Severity: How "important" the rule is.
  • Max alerts: The maximum number of alerts sent for the event. -1 means unlimited.
  • Delay: The amount of time in seconds to wait after a rule is matched before sending an alert out transport.
  • Interval: The interval of time in seconds between alerts for an event until Max alert is reached.
  • Mute alerts: Disables sending alert rule through alert transport. But will still show the alert in the Web UI.
  • Invert match: Invert the matching rule (ie. alert on items that _don't match the rule).
  • Recovery alerts: This will disable the recovery notification from being sent if turned off.

Advanced

On the Advanced tab, you can specify some additional options for the alert rule:

  • Override SQL: Enable this if you using a custom query

  • Query: The query to be used for the alert.

  • An example of this would be an average rule for all CPUs over 10%

SELECT devices.*,AVG(processors.processor_usage) AS cpu_avg, processors.* FROM 
devices INNER JOIN processors ON devices.device_id 
= processors.device_id WHERE devices.device_id 
= ? AND devices.status = 1 AND devices.disabled = 
0 AND devices.ignore = 0 GROUP BY devices.device_id, 
devices.status, devices.disabled, devices.ignore 
HAVING AVG(processors.processor_usage) 
> 10;

The 10 would then contain the average CPU usage value, you can change this value to be whatever you like.

  • You will to need copy and paste this into the Alert Rule under Advanced then paste into Query box and switch the Override SQL.

Procedure

You can associate a rule to a procedure by giving the URL of the procedure when creating the rule. Only links like "http://" are supported, otherwise an error will be returned. Once configured, procedure can be opened from the Alert widget through the "Open" button, which can be shown/hidden from the widget configuration box.

Examples

Alert when:

  • Device goes down: devices.status != 1
  • Any port changes: ports.ifOperStatus != 'up'
  • Root-directory gets too full: storage.storage_descr = '/' AND storage.storage_perc >= '75'
  • Any storage gets fuller than the 'warning': storage.storage_perc >= storage_perc_warn
  • If device is a server and the used storage is above the warning level, but ignore /boot partitions: storage.storage_perc > storage.storage_perc_warn AND devices.type = "server" AND storage.storage_descr != "/boot"
  • VMware LAG is not using "Source ip address hash" load balancing: devices.os = "vmware" AND ports.ifType = "ieee8023adLag" AND ports.ifDescr REGEXP "Link Aggregation .*, load balancing algorithm: Source ip address hash"
  • Syslog, authentication failure during the last 5m: syslog.timestamp >= macros.past_5m AND syslog.msg REGEXP ".*authentication failure.*"
  • High memory usage: macros.device_up = 1 AND mempools.mempool_perc >= 90 AND mempools.mempool_descr REGEXP "Virtual.*"
  • High CPU usage(per core usage, not overall): macros.device_up = 1 AND processors.processor_usage >= 90
  • High port usage, where description is not client & ifType is not softwareLoopback: macros.port_usage_perc >= 80 AND port.port_descr_type != "client" AND ports.ifType != "softwareLoopback"
  • Alert when mac address is located on your network ipv4_mac.mac_address = "2c233a756912"

Alert Rules Collection

You can also select Alert Rule from the Alerts Collection. These Alert Rules are submitted by users in the community :) If would like to submit your alert rules to the collection, please submit them here Alert Rules Collection

Alert Rules Collection