## VM Alert
`vmalert` executes a list of given MetricsQL expressions (rules) and
sends alerts to [Alert Manager](https://github.com/prometheus/alertmanager).
### Features:
* Integration with [VictoriaMetrics](https://github.com/VictoriaMetrics/VictoriaMetrics) TSDB;
* VictoriaMetrics [MetricsQL](https://github.com/VictoriaMetrics/VictoriaMetrics/wiki/MetricsQL)
expressions validation;
* Prometheus [alerting rules definition format](https://prometheus.io/docs/prometheus/latest/configuration/alerting_rules/#defining-alerting-rules)
support;
* Integration with [Alertmanager](https://github.com/prometheus/alertmanager);
* Lightweight without extra dependencies.
### TODO:
* Support recording rules.
### 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](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/app/vmalert/testdata/rules0-good.rules)
`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.
### How to build from sources
It is recommended using
[binary releases](https://github.com/VictoriaMetrics/VictoriaMetrics/releases)
- `vmalert` is located in `vmutils-*` archives there.
#### Development build
1. [Install Go](https://golang.org/doc/install). The minimum supported version is Go 1.13.
2. Run `make vmalert` from the root folder of the repository.
It builds `vmalert` binary and puts it into the `bin` folder.
#### Production build
1. [Install docker](https://docs.docker.com/install/).
2. Run `make vmalert-prod` from the root folder of the repository.
It builds `vmalert-prod` binary and puts it into the `bin` folder.