6dca5b26d1
Replace http.Serve() with http.Server{} configured with timeouts to
address G114 gosec findings (HTTP server without timeouts). This
prevents potential slowloris attacks and resource exhaustion.
Changes:
- Add ReadTimeout, WriteTimeout, IdleTimeout (5s each) to HTTP servers
- Use srv.Shutdown(ctx) for graceful shutdown instead of ln.Close()
- Follow existing pattern from plugin/metrics
Fixes part of #7793
Signed-off-by: Azeez Syed <syedazeez337@gmail.com>
health
Name
health - enables a health check endpoint.
Description
Enabled process wide health endpoint. When CoreDNS is up and running this returns a 200 OK HTTP status code. The 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 this server is healthy.
An extra option can be set with this extended syntax:
health [ADDRESS] {
lameduck DURATION
}
- Where
lameduckwill delay shutdown for DURATION. /health will still answer 200 OK. Note: The ready plugin will not answer OK while CoreDNS is in lame duck mode prior to shutdown.
If you have multiple Server Blocks, health can only be enabled in one of them (as it is process wide). If you really need multiple endpoints, you must run health endpoints on different ports:
com {
whoami
health :8080
}
net {
erratic
health :8081
}
Doing this is supported but both endpoints ":8080" and ":8081" will export the exact same health.
Metrics
If monitoring is enabled (via the prometheus plugin) then the following metrics are exported:
coredns_health_request_duration_seconds{}- The health plugin performs a self health check once per second on the/healthendpoint. This metric is the duration to process that request. As this is a local operation it should be fast. A (large) increase in this duration indicates the CoreDNS process is having trouble keeping up with its query load.coredns_health_request_failures_total{}- The number of times the self health check failed.
Note that these metrics do not have a server label, because being overloaded is a symptom of
the running process, not a specific server.
Examples
Run another health endpoint on http://localhost:8091.
. {
health localhost:8091
}
Set a lame duck duration of 1 second:
. {
health localhost:8092 {
lameduck 1s
}
}