coredns/plugin/health/README.md

# health

## Name

*health* - enables a health check endpoint.

## Description

By enabling *health* any plugin that implements it 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.

## Plugins

Any plugin that implements the Healther interface will be used to report health.

## Examples

Run another health endpoint on http://localhost:8091.

~~~ corefile
. {
    health localhost:8091
}
~~~
A health middleware Start http handler on port 8080 and return OK. Also add some documentation fixes for the prometheus middleware. 2016-04-06 09:21:46 +01:00			`# health`

Manual pages (#1346) * Add manual pages Generate manual pages from the README and extend README with Name and Description sections. The generation requires 'ronn' which may not be available. Just check in all generated manual pages. 2018-01-04 12:53:07 +00:00			`## Name`
docs: less CoreDNS in docs (#1154) Various other changes. 2017-10-20 09:47:43 +01:00
Manual pages (#1346) * Add manual pages Generate manual pages from the README and extend README with Name and Description sections. The generation requires 'ronn' which may not be available. Just check in all generated manual pages. 2018-01-04 12:53:07 +00:00			`health - enables a health check endpoint.`

			`## Description`

			`By enabling health any plugin that implements it will be queried for it's health. The combined`
			`health is exported, by default, on port 8080/health .`
A health middleware Start http handler on port 8080 and return OK. Also add some documentation fixes for the prometheus middleware. 2016-04-06 09:21:46 +01:00
			`## Syntax`

			`~~~`
docs: rewrite using manpage style (#327) This still needs cleanup, but this is a first pass the cleans some cruft and documents our style (in middleware.md) and makes all the docs match that style. 2016-10-10 20:13:22 +01:00			`health [ADDRESS]`
A health middleware Start http handler on port 8080 and return OK. Also add some documentation fixes for the prometheus middleware. 2016-04-06 09:21:46 +01:00			`~~~`

mw/health: poll other middleware (#976) This add the infrastructure to let other middleware report their health status back to the health middleware. A health.Healther interface is introduced and a middleware needs to implement that. A middleware that supports healthchecks is statically configured. Every second each supported middleware is queried and the global health state is updated. Actual tests have been disabled as no other middleware implements this at the moment. 2017-08-27 21:33:38 +01:00			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`
Remove the word middleware (#1067) * Rename middleware to plugin first pass; mostly used 'sed', few spots where I manually changed text. This still builds a coredns binary. * fmt error * Rename AddMiddleware to AddPlugin * Readd AddMiddleware to remain backwards compat 2017-09-14 09:36:06 +01:00			`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`
mw/health: poll other middleware (#976) This add the infrastructure to let other middleware report their health status back to the health middleware. A health.Healther interface is introduced and a middleware needs to implement that. A middleware that supports healthchecks is statically configured. Every second each supported middleware is queried and the global health state is updated. Actual tests have been disabled as no other middleware implements this at the moment. 2017-08-27 21:33:38 +01:00			`supports health checks has a section "Health" in their README.`
A health middleware Start http handler on port 8080 and return OK. Also add some documentation fixes for the prometheus middleware. 2016-04-06 09:21:46 +01:00
plugin/health: implement dyn health checks (#1214) Implement health.Healther in erratic and kubernetes plugin. The kubernetes' healtcheck is only performed on startup - i.e. turn healthy after the initial loading. Erratic follow the drop count: every query%drop turns the healthcheck unhealthy. Fixes: #985 2017-11-13 09:52:40 +00:00			`## Plugins`

Instead of hardcoding plugin lists in autopath/health, use interfaces. (#1306) Switched health and autopath plugin to allow any plugins to be used instead of a hardcoded list. I did not switch federation over since it wasn't obvious that anything other than kubernetes could be used with it. Fixes #1291 2017-12-12 15:40:30 -05:00			`Any plugin that implements the Healther interface will be used to report health.`
plugin/health: implement dyn health checks (#1214) Implement health.Healther in erratic and kubernetes plugin. The kubernetes' healtcheck is only performed on startup - i.e. turn healthy after the initial loading. Erratic follow the drop count: every query%drop turns the healthcheck unhealthy. Fixes: #985 2017-11-13 09:52:40 +00:00
A health middleware Start http handler on port 8080 and return OK. Also add some documentation fixes for the prometheus middleware. 2016-04-06 09:21:46 +01:00			`## Examples`
pprof middleware (#138) Add pprof middleware, enabled by pprof directive. 2016-04-28 10:26:58 +01:00
mw/health: poll other middleware (#976) This add the infrastructure to let other middleware report their health status back to the health middleware. A health.Healther interface is introduced and a middleware needs to implement that. A middleware that supports healthchecks is statically configured. Every second each supported middleware is queried and the global health state is updated. Actual tests have been disabled as no other middleware implements this at the moment. 2017-08-27 21:33:38 +01:00			`Run another health endpoint on http://localhost:8091.`

doc update (#1140) * doc update Go through all README and fix mistakes, extend example and let more corefile snippets be test for validity. * Cant use spefic addr in test 2017-10-10 09:39:35 +02:00			`~~~ corefile`
			`. {`
			`health localhost:8091`
			`}`
pprof middleware (#138) Add pprof middleware, enabled by pprof directive. 2016-04-28 10:26:58 +01:00			`~~~`