2338120f5b
This registers the Collectors iff the metrics plugin has been loaded. Safes a bunch of code in each and every plugin's setup code.
health
Name
health - enables a health check endpoint.
Description
By enabling health any plugin that implements healt.Healther interface will be queried for it's health. The combined health is exported, by default, on port 8080/health .
Syntax
health [ADDRESS]
Optionally takes an address; the default is :8080. The health path is fixed to /health. The
health endpoint returns a 200 response code and the word "OK" when CoreDNS is healthy. It returns
a 503. health periodically (1s) polls plugin that exports health information. If any of the
plugin signals that it is unhealthy, the server will go unhealthy too. Each plugin that supports
health checks has a section "Health" in their README.
More options can be set with this extended syntax:
health [ADDRESS] {
lameduck DURATION
}
- Where
lameduckwill make the process unhealthy then wait for DURATION before the process shuts down.
If you have multiple Server Block and need to export health for each of the plugins, you must run health endpoints on different ports:
com {
whoami
health :8080
}
net {
erratic
health :8081
}
Plugins
Any plugin that implements the Healther interface will be used to report health.
Metrics
If monitoring is enabled (via the prometheus directive) then the following metric is exported:
coredns_health_request_duration_seconds{}- duration to process a /health query. As this should be a local operation it should be fast. A (large) increases in this duration indicates the CoreDNS process is having trouble keeping up with its query load.
Examples
Run another health endpoint on http://localhost:8091.
. {
health localhost:8091
}
Set a lameduck duration of 1 second:
. {
health localhost:8092 {
lameduck 1s
}
}