2c341ee755
This PR includes various fixes to anchor links used in the documentation. There are certain characters GitHub doesn't support for the use of anchor links in markdown files. The general rule I've found is to only use a-z or A-Z characters in anchor links. All other characters should be removed. For example, consider the section title How do I connect to the Mailhog simulated server?. The valid GitHub anchor link for this section is #how-do-i-connect-to-the-mailhog-simulated-server. Notice no ?. Closes #494
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Monitoring Fleet
Health checks
Fleet exposes a basic health check at the /healthz endpoint. This is the interface to use for simple monitoring and load-balancer health checks.
The /healthz endpoint will return an HTTP 200 status if the server is running and has healthy connections to MySQL and Redis. If there are any problems, the endpoint will return an HTTP 500 status.
Metrics
Fleet exposes server metrics in a format compatible with Prometheus. A simple example Prometheus configuration is available in tools/app/prometheus.yml.
Prometheus can be configured to use a wide range of service discovery mechanisms within AWS, GCP, Azure, Kubernetes, and more. See the Prometheus configuration documentation for more information on configuring the
Alerting
Prometheus has built-in support for alerting through Alertmanager.
Consider building alerts for
- Changes from expected levels of host enrollment
- Increased latency on HTTP endpoints
- Increased error levels on HTTP endpoints
TODO (Seeking Contributors)
Add example alerting configurations
Graphing
Prometheus provides basic graphing capabilities, and integrates tightly with Grafana for sophisticated visualizations.
Fleet server performance
Fleet is designed to scale to hundreds of thousands of online hosts. The Fleet server scales horizontally to support higher load.
Horizontal scaling
Scaling Fleet horizontally is as simple as running more Fleet server processes connected to the same MySQL and Redis backing stores. Typically, operators front Fleet server nodes with a load balancer that will distribute requests to the servers. All APIs in Fleet are designed to work in this arrangement by simply configuring clients to connect to the load balancer.
Availability
The Fleet/osquery system is resilient to loss of availability. Osquery agents will continue executing the existing configuration and buffering result logs during downtime due to lack of network connectivity, server maintenance, or any other reason. Buffering in osquery can be configured with the --buffered_log_max flag.
Note that short downtimes are expected during Fleet server upgrades-fleet.md) that require database migrations.
Monitoring
More information on monitoring Fleet servers with Prometheus and other tools is available in the Monitoring Fleet documentation.
Debugging performance issues
MySQL and Redis
If performance issues are encountered with the MySQL and Redis servers, use the extensive resources available online to optimize and understand these problems. Please file an issue with details about the problem so that Fleet developers can work to fix them.
Fleet server
For performance issues in the Fleet server process, please file an issue with details about the scenario, and attach a debug archive. Debug archives can also be submitted confidentially through other support channels.
Generate debug archive (Fleet 3.4.0+)
Use the fleetctl archive command to generate an archive of Fleet's full suite of debug profiles. See the fleetctl setup guide) for details on configuring fleetctl.
The generated .tar.gz archive will be available in the current directory.
Targeting individual servers
In most configurations, the fleetctl client is configured to make requests to a load balancer that will proxy the requests to each server instance. This can be problematic when trying to debug a performance issue on a specific server. To target an individual server, create a new fleetctl context that uses the direct address of the server.
For example:
fleetctl config set --context server-a --address https://server-a:8080
fleetctl login --context server-a
fleetctl debug archive --context server-a
Confidential information
The fleetctl archive command retrieves information generated by Go's net/http/pprof package. In most scenarios this should not include sensitive information, however it does include command line arguments to the Fleet server. If the Fleet server receives sensitive credentials via CLI argument (not environment variables or config file), this information should be scrubbed from the archive in the cmdline file.