VictoriaMetrics/app/vmalert/README.md

VM Alert

vmalert executes a list of given MetricsQL expressions (rules) and sends alerts to Alert Manager.

Features:

• Integration with VictoriaMetrics TSDB;
• VictoriaMetrics MetricsQL expressions validation;
• Prometheus alerting rules definition format support;
• Integration with Alertmanager;
• Lightweight without extra dependencies.

TODO:

• Configuration hot reload.

QuickStart

To build vmalert from sources:

git clone https://github.com/VictoriaMetrics/VictoriaMetrics
cd VictoriaMetrics
make vmalert

The build binary will be placed to VictoriaMetrics/bin folder.

To start using vmalert you will need the following things:

• list of alert rules - PromQL/MetricsQL expressions to execute;
• datasource address - reachable VictoriaMetrics instance for rules execution;
• notifier address - reachable Alertmanager instance for processing, aggregating alerts and sending notifications.

Then configure vmalert accordingly:

./bin/vmalert -rule=alert.rules \
		-datasource.url=http://localhost:8428 \
        -notifier.url=http://localhost:9093

Example for .rules file may be found here

vmalert runs evaluation for every group in a separate goroutine. Rules in group evaluated one-by-one sequentially.

vmalert also runs a web-server (-httpListenAddr) for serving metrics and alerts endpoints:

• http://<vmalert-addr>/api/v1/alerts - list of all active alerts;
• http://<vmalert-addr>/api/v1/<groupName>/<alertID>/status" - get alert status by ID. Used as alert source in AlertManager.
• http://<vmalert-addr>/metrics - application metrics.
• http://<vmalert-addr>/-/reload - hot configuration reload.

vmalert may be configured with -remoteWrite flag to write alerts state in form of timeseries via remote write protocol. Alerts state will be written as ALERTS timeseries. These timeseries may be used to recover alerts state on vmalert restarts if -remoteRead is configured.

Configuration

The shortlist of configuration flags is the following:

Usage of vmalert:
  -datasource.basicAuth.password string
        Optional basic auth password for -datasource.url
  -datasource.basicAuth.username string
        Optional basic auth username for -datasource.url
  -datasource.url string
        Victoria Metrics or VMSelect url. Required parameter. E.g. http://127.0.0.1:8428
  -enableTCP6
        Whether to enable IPv6 for listening and dialing. By default only IPv4 TCP is used
  -evaluationInterval duration
        How often to evaluate the rules. Default 1m (default 1m0s)
  -external.url string
        External URL is used as alert's source for sent alerts to the notifier
  -http.maxGracefulShutdownDuration duration
        The maximum duration for graceful shutdown of HTTP server. Highly loaded server may require increased value for graceful shutdown (default 7s)
  -httpAuth.password string
        Password for HTTP Basic Auth. The authentication is disabled if -httpAuth.username is empty
  -httpAuth.username string
        Username for HTTP Basic Auth. The authentication is disabled if empty. See also -httpAuth.password
  -httpListenAddr string
        Address to listen for http connections (default ":8880")
  -notifier.url string
        Prometheus alertmanager URL. Required parameter. e.g. http://127.0.0.1:9093
  -remoteRead.basicAuth.password string
        Optional basic auth password for -remoteRead.url
  -remoteRead.basicAuth.username string
        Optional basic auth username for -remoteRead.url
  -remoteRead.lookback duration
        Lookback defines how far to look into past for alerts timeseries. For example, if lookback=1h then range from now() to now()-1h will be scanned. (default 1h0m0s)
  -remoteRead.url vmalert
        Optional URL to Victoria Metrics or VMSelect that will be used to restore alerts state. This configuration makes sense only if vmalert was configured with `remoteWrite.url` before and has been successfully persisted its state. E.g. http://127.0.0.1:8428
  -remoteWrite.basicAuth.password string
        Optional basic auth password for -remoteWrite.url
  -remoteWrite.basicAuth.username string
        Optional basic auth username for -remoteWrite.url
  -remoteWrite.maxQueueSize
	    Defines the max number of pending datapoints to remote write endpoint
  -remoteWrite.url string
        Optional URL to Victoria Metrics or VMInsert where to persist alerts state in form of timeseries. E.g. http://127.0.0.1:8428
  -rule value
        Path to the file with alert rules. 
        Supports patterns. Flag can be specified multiple times. 
        Examples:
         -rule /path/to/file. Path to a single file with alerting rules
         -rule dir/*.yaml -rule /*.yaml. Relative path to all .yaml files in "dir" folder, 
        absolute path to all .yaml files in root.
  -rule.validateTemplates
        Indicates to validate annotation and label templates (default true)

Pass -help to vmalert in order to see the full list of supported command-line flags with their descriptions.

To reload configuration without vmalert restart send SIGHUP signal or send GET request to /-/reload endpoint.

Contributing

vmalert is mostly designed and built by VictoriaMetrics community. Feel free to share your experience and ideas for improving this software. Please keep simplicity as the main priority.