Watchdog: Check Types

All 15 built-in Watchdog check types with runner assignment, status logic and links to each type's reference, plus how to add a check.

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Watchdog: Check Types

Watchdog ships 15 built-in check types. Each type defines where it may run.

Mode	Where the check runs
Dashboard	Only in the dashboard's worker container. The type needs a URL from the client record
Agent	Only on an agent. The type needs direct access to the machine
Dashboard or Agent	Network-level check that can run from either side

Built-in checks

Check	Type identifier	Runner	Tests
HTTP Reachability	`http`	Dashboard	Whether a URL returns an expected status code
HTTP Content	`http_content`	Dashboard	Whether the response body contains or lacks given strings
SSL Certificate	`ssl_cert`	Dashboard	Remaining validity of the TLS certificates of several hosts
DNS	`dns`	Dashboard or Agent	Whether a host name resolves, optionally to an expected IP
TCP Port	`tcp_port`	Dashboard or Agent	Whether a TCP port accepts connections
Redis	`redis`	Dashboard or Agent	PING to a Redis server and a PONG reply
Database	`database`	Dashboard or Agent	Whether a PDO connection can be established
Docker Container Health	`docker`	Dashboard or Agent	Running and health state of a container
Docker Exec	`docker_exec`	Dashboard or Agent	Exit code of a command inside a container
Disk Space	`disk_space`	Agent	Usage of a mount point in percent
Load Average	`load_average`	Agent	System load relative to the CPU count
Process Running	`process`	Agent	Whether a process is running
Log File	`log_file`	Agent	Freshness of a log file and a pattern inside it
File Age	`file_age`	Agent	How long a file has gone unmodified
File Size	`file_size`	Agent	Whether a file's size is within the allowed range

Adding a check

Open the client and click + Add check.
Pick the Check type. The form shows the type's fields.
Pick the Runner. Types that allow only one side set the runner themselves. For runner Agent you also pick the Agent.
Set interval or daily time and the retention, see Configuration.
Save. Dashboard checks run on the next one-minute tick of the scheduler container, agent checks on the agent's next tick.

Use Run now to start a check immediately.

Common rules

Defaults: Fields you leave empty are replaced by the type's defaults when the check runs. If you leave all fields empty, the type's defaults are stored.
Status UNKNOWN: A check returns UNKNOWN when it cannot run meaningfully, for example with missing configuration or a missing Docker socket. This does not trigger a failure email.
Status WARN and FAIL: Both trigger a failure email on the change from OK or UNKNOWN, see Notifications.
Response time: In dashboard mode only HTTP Reachability and HTTP Content record a response time. For agent checks the agent measures the duration of each run and reports it as the response time.
Timeouts: Several types have a Timeout (seconds) field. TCP and Redis clamp the value to 1 to 60 seconds, Database to 1 to 30 seconds.

Custom checks

The check system is extensible. A PHP class implementing CheckInterface and tagged watchdog.check appears in the selection automatically. See Writing Custom Checks.