Check types

Synthetic Monitoring checks are tests that run on selected public or private probes at frequent intervals to continuously verify your systems.

Checks save results as Prometheus metrics and Loki logs, enabling the configuration of Grafana alerts for custom notifications and incident management.

Synthetic Monitoring supports various check types with distinct capabilities.

DNS checks ensures a domain name server resolves and measures the average time for the resolution to happen. They can be set up to validate against a specific DNS server and check for a specific kind of response.
HTTP checks are used to test an HTTP endpoint, measuring the uptime and response latency. These checks can also be configured for more advanced tests, like if a site is using a specific version of SSL, for SSL certificate expiration, or if HTTP automatically redirects to HTTPS.
MultiHTTP checks can test multiple URLs in a single check. You can also use the results of one request in a later one and make several assertions for each request.
Ping checks are the simplest check that can test whether an endpoint is available. Target servers must be configured to reply to ICMP echo requests and measure the response latency.
TCP checks connects to an endpoint on a given hostname or IP address and a port. This ensures a server accepts the connection and measures response latency and uptime.
Traceroute checks runs a traceroute from probes to targets. You can visualize the path of a request and get more detailed information about how that path is changing over time.

Common options

Each check type has specific options. The following is a list of options common to all check types.

Option	Description
Enabled	Whether the check is enabled or not.
Job name	Refer to the check name. Check metrics include a `job` label with the value of this option.
Target	Target of the check request. Check metrics include an `instance` label with the value of this option.
Probe locations	The locations where the check should run from. Check metrics include a `probe` label with the value of the probe location running the check.
Frequency	The frequency the check should run in seconds. The value can range from 60 to 3600 seconds. Only the `sm_check_info` metric includes the `frequency` label.
Timeout	Maximum execution time for the check. The value can range from 1 to 60 seconds.
Custom labels	(Optional) Custom labels applied to check metrics. Refer to Custom labels for querying instructions.

Note
Check identifier: all checks include the Job name and Target options, which together uniquely identify the check.

Common check metrics

Checks collect the results of the execution and save them as Prometheus metrics.

Each check type produces specific Prometheus metrics with their results. The following is a list of metrics common to all check types.

Metric	Description
`probe_all_duration_seconds`	Returns how long the probe took to complete in seconds (histogram).
`probe_duration_seconds`	Returns how long the probe took to complete in seconds.
`probe_all_success`	Displays whether or not the probe was a success (summary).
`probe_success`	Displays whether or not the probe was a success.
`sm_check_info`	Provides information about a single check configuration.

For the list of additional metrics, refer to the metrics documentation for each check type: DNS metrics, HTTP metrics, MultiHTTP metrics, Ping metrics, TCP metrics, and Traceroute metrics.

Metric labels

In Prometheus, labels adds additional context to the metrics, and can be used for querying and visualizations.

Some check options include specific labels to the resulting metrics to provide additional information.

Option	Label	Metrics
Job name	Include a `job` label with the value of this option.	All metrics
Target	Include an `instance` label with the value of this option.	All metrics
Probe locations	Include a `probe` label with the value of the probe location running the check.	All check metrics
Frequency	Include a `frequency` label with the value of this option.	`sm_check_info`
Custom labels	(Optional) Include your custom labels. Refer to Custom labels for querying instructions.	All check metrics