106 lines
2.3 KiB
Groff
106 lines
2.3 KiB
Groff
.\" generated with Ronn/v0.7.3
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.\" http://github.com/rtomayko/ronn/tree/0.7.3
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.
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.TH "COREDNS\-HEALTH" "7" "March 2018" "CoreDNS" "CoreDNS plugins"
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.
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.SH "NAME"
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\fIhealth\fR \- enables a health check endpoint\.
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.
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.SH "DESCRIPTION"
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By enabling \fIhealth\fR any plugin that implements healt\.Healther interface \fIhttps://godoc\.org/github\.com/coredns/coredns/plugin/health#Healther\fR will be queried for it\'s health\. The combined health is exported, by default, on port 8080/health \.
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.
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.SH "SYNTAX"
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.
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.nf
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health [ADDRESS]
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.
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.fi
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.
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.P
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Optionally takes an address; the default is \fB:8080\fR\. The health path is fixed to \fB/health\fR\. The health endpoint returns a 200 response code and the word "OK" when CoreDNS is healthy\. It returns a 503\. \fIhealth\fR 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\.
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.
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.P
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More options can be set with this extended syntax:
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.
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.IP "" 4
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.
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.nf
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health [ADDRESS] {
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lameduck DURATION
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}
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.
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.fi
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.
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.IP "" 0
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.
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.IP "\(bu" 4
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Where \fBlameduck\fR will make the process unhealthy then \fIwait\fR for \fBDURATION\fR before the process shuts down\.
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.
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.IP "" 0
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.
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.P
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If you have multiple Server Block and need to export health for each of the plugins, you must run health endpoints on different ports:
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.
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.IP "" 4
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.
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.nf
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com {
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whoami
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health :8080
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}
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net {
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erratic
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health :8081
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}
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.
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.fi
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.
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.IP "" 0
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.
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.SH "PLUGINS"
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Any plugin that implements the Healther interface will be used to report health\.
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.
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.SH "METRICS"
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If monitoring is enabled (via the \fIprometheus\fR directive) then the following metric is exported:
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.
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.IP "\(bu" 4
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\fBcoredns_health_request_duration_seconds{}\fR \- 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\.
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.
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.IP "" 0
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.
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.SH "EXAMPLES"
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Run another health endpoint on http://localhost:8091\.
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.
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.IP "" 4
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.
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.nf
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\&\. {
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health localhost:8091
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}
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.
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.fi
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.
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.IP "" 0
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.
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.P
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Set a lameduck duration of 1 second:
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.
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.IP "" 4
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.
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.nf
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\&\. {
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health localhost:8092 {
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lameduck 1s
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}
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}
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.
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.fi
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.
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.IP "" 0
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