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librenms-librenms/doc/Alerting/Rules.md
kiwibrew c91691bfa6 Update Rules.md (#14505)
Removed links to videos about how to create rules. The videos no longer describe the process for adding rules or wildcards. The new alerting UI is too different from the old one for them to be useful.
2022-10-24 21:26:42 -05:00

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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](Macros.md)
## 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%
```sql
SELECT *,AVG(processors.processor_usage) as cpu_avg FROM
devices,processors WHERE (devices.device_id = ? AND devices.device_id
= processors.device_id) AND (devices.status = 1 && (devices.disabled =
0 && devices.ignore = 0)) = 1 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](https://github.com/librenms/librenms/blob/master/misc/alert_rules.json)
![Alert Rules Collection](/img/alert-rules-collection.png)