Monitor GitLab Runner usage

GitLab Runner can be monitored using Prometheus.

Embedded Prometheus metrics

GitLab Runner is instrumented with native Prometheus metrics, which can be exposed by using an embedded HTTP server on the /metrics path. The server - if enabled - can be scraped by the Prometheus monitoring system or accessed with any other HTTP client.

The exposed information includes:

• Runner business logic metrics (for example, the number of jobs running at the moment)
• Go-specific process metrics (for example, garbage collection stats, goroutines, and memstats)
• general process metrics (memory usage, CPU usage, file descriptor usage, etc.)
• build version information

The metrics format is documented in Prometheus' Exposition formats specification.

These metrics are meant as a way for operators to monitor and gain insight into your runners. For example, you might want to know if an increase in load average on the runner host is related to an increase in processed jobs. Or perhaps you are running a cluster of machines, and you want to track build trends so you can make changes to your infrastructure.

Learning more about Prometheus

To set up Prometheus server to scrape this HTTP endpoint and use the collected metrics, see Prometheus’s getting started guide. For more details on how to configure Prometheus, see the configuration section. For more details about alert configuration, see alerting rules and Alertmanager.

Available metrics

To find a full list of all available metrics, curl the metrics endpoint after it is configured and enabled. For example, for a local runner configured with listening port 9252:

$ curl -s "http://localhost:9252/metrics" | grep -E "# HELP"

# HELP gitlab_runner_api_request_statuses_total The total number of api requests, partitioned by runner, endpoint and status.
# HELP gitlab_runner_autoscaling_machine_creation_duration_seconds Histogram of machine creation time.
# HELP gitlab_runner_autoscaling_machine_states The current number of machines per state in this provider.
# HELP gitlab_runner_concurrent The current value of concurrent setting
# HELP gitlab_runner_errors_total The number of caught errors.
# HELP gitlab_runner_limit The current value of limit setting
# HELP gitlab_runner_request_concurrency The current number of concurrent requests for a new job
# HELP gitlab_runner_request_concurrency_exceeded_total Count of excess requests above the configured request_concurrency limit
# HELP gitlab_runner_version_info A metric with a constant '1' value labeled by different build stats fields.
...

The list includes Go-specific process metrics. For a list of available metrics that do not include Go-specific processes, see Monitoring runners.

pprof HTTP endpoints

The internal state of the GitLab Runner process through metrics is valuable, but in some cases you must examine the Running process in real time. That’s why we’ve introduced the pprof HTTP endpoints.

pprof endpoints are available through an embedded HTTP server on /debug/pprof/ path.

You can read more about using pprof in its documentation.

Configuration of the metrics HTTP server

Configure the metrics HTTP server by using one of the following methods:

• Use the listen_address global configuration option in the config.toml file.

• Use the --listen-address command line option for the run command.

• For runners using Helm chart, in the values.yaml:

  1. Configure the metrics option:

     ## Configure integrated Prometheus metrics exporter
     ##
     ## ref: https://docs.gitlab.com/runner/monitoring/#configuration-of-the-metrics-http-server
     ##
     metrics:
       enabled: true
     
       ## Define a name for the metrics port
       ##
       portName: metrics
     
       ## Provide a port number for the integrated Prometheus metrics exporter
       ##
       port: 9252
     
       ## Configure a prometheus-operator serviceMonitor to allow autodetection of
       ## the scraping target. Requires enabling the service resource below.
       ##
       serviceMonitor:
         enabled: true
     
         ...

  2. Configure the service monitor to retrieve the configured metrics:

     ## Configure a service resource to allow scraping metrics by uisng
     ## prometheus-operator serviceMonitor
     service:
       enabled: true
     
       ## Provide additonal labels for the service
       ##
       labels: {}
     
       ## Provide additonal annotations for the service
       ##
       annotations: {}
     
       ...

If you add the address to your config.toml file, to start the metrics HTTP server, you must restart the runner process.

In both cases the option accepts a string with the format [host]:<port>, where:

• host can be an IP address or a hostname,
• port is a valid TCP port or symbolic service name (like http). You should use port 9252 which is already allocated in Prometheus.

If the listen address does not contain a port, it defaults to 9252.

Examples of addresses:

• :9252 listens on all interfaces on port 9252.
• localhost:9252listens on the loopback interface on port 9252.
• [2001:db8::1]:http listens on IPv6 address [2001:db8::1] on the HTTP port 80.

Remember that for listening on ports below 1024 - at least on Linux/Unix systems - you need to have root/administrator rights.

The HTTP server is opened on the selected host:port without any authorization. If you bind the metrics server to a public interface, use your firewall limit access or add an HTTP proxy for authorization and access control.