This set of parameters is used to control the way how the backend checks will be done. Such active checks can be really useful for `stale-if-error` caching technique and especially in case if backend is very slow to reply or to connect to.
`backend-active-check-http-method` can be used to configure the HTTP method used to check the backend. Special method `CONNECT` can be used to check only for connection attempt.
Please be aware that the `backend-active-check-timeout` is really short by default, so in case if `/` of the backend is slow to reply configure proper path with `backend-active-check-http-path` to not mark such backend down too fast, before increasing the check timeout.
"description":"Enables active checks of the backend. For HTTP level checks the HTTP code shall be 2xx or 3xx, otherwise backend will be considered down.",
"enum":[
"false",
"true"
],
"default":"false",
"type":"string"
},
"backend-active-check-http-method":{
"title":"Backend Active Check HTTP Metod",
"description":"Selects method to do the active check. CONNECT means that connection will be enough for the check, otherwise it's HTTP method.",
"enum":[
"GET",
"OPTIONS",
"POST",
"CONNECT"
],
"default":"GET",
"type":"string"
},
"backend-active-check-http-path":{
"title":"Backend Active Check HTTP Path",
"description":"A path on which do the active check, unused in case of CONNECT.",
"default":"/",
"type":"string"
},
"backend-active-check-http-version":{
"title":"Backend Active Check HTTP Version",
"description":"A HTTP version to use to check the backend, unused in case of CONNECT.",
"enum":[
"HTTP/1.1",
"HTTP/1.0"
],
"default":"HTTP/1.1",
"type":"string"
},
"backend-active-check-timeout":{
"title":"Backend Active Check Timeout (seconds)",
"description":"A timeout to for the request to be fulfilled, after connection happen.",
"default":"2",
"type":"integer"
},
"backend-active-check-interval":{
"title":"Backend Active Check Interval (seconds)",
"description":"An interval of backend active check.",
"default":"5",
"type":"integer"
},
"backend-active-check-rise":{
"title":"Backend Active Check Rise",
"description":"Amount of correct responses from the backend to consider it up.",
"default":"1",
"type":"integer"
},
"backend-active-check-fall":{
"title":"Backend Active Check Fall",
"description":"Amount of bad responses from the backend to consider it down.",