From 7b1edea5524f01fe46e717c08615ccd483346a5b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Nussbaumer?=
 <clement.nussbaumer@postfinance.ch>
Date: Tue, 6 Feb 2024 16:59:42 +0100
Subject: [PATCH] feat: use controller-runtime's client with integrated caching
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

permits to get rid of kubediscovery package and to simplify the codebase

linked to: https://github.com/postfinance/kubenurse/issues/55

Signed-off-by: Clément Nussbaumer <clement.nussbaumer@postfinance.ch>
---
 go.mod                                       |  22 ++--
 go.sum                                       |  61 ++++++++---
 internal/kubediscovery/kubediscovery.go      | 106 -------------------
 internal/kubediscovery/kubediscovery_test.go |  55 ----------
 internal/kubediscovery/nodewatcher.go        |  82 --------------
 internal/kubediscovery/nodewatcher_test.go   |  45 --------
 internal/kubenurse/handler.go                |   5 +-
 internal/kubenurse/handler_test.go           |   6 +-
 internal/kubenurse/k8s-auth.go               |   7 ++
 internal/kubenurse/server.go                 |  12 +--
 internal/kubenurse/server_test.go            |   5 +-
 internal/servicecheck/neighbours.go          |  83 +++++++++++++++
 internal/servicecheck/servicecheck.go        |  30 +-----
 internal/servicecheck/servicecheck_test.go   |  16 ++-
 internal/servicecheck/types.go               |  17 +--
 main.go                                      |  48 +++++++--
 16 files changed, 219 insertions(+), 381 deletions(-)
 delete mode 100644 internal/kubediscovery/kubediscovery.go
 delete mode 100644 internal/kubediscovery/kubediscovery_test.go
 delete mode 100644 internal/kubediscovery/nodewatcher.go
 delete mode 100644 internal/kubediscovery/nodewatcher_test.go
 create mode 100644 internal/kubenurse/k8s-auth.go
 create mode 100644 internal/servicecheck/neighbours.go

diff --git a/go.mod b/go.mod
index 3abcf266..49394839 100644
--- a/go.mod
+++ b/go.mod
@@ -10,6 +10,7 @@ require (
 	k8s.io/api v0.29.0
 	k8s.io/apimachinery v0.29.0
 	k8s.io/client-go v0.29.0
+	sigs.k8s.io/controller-runtime v0.17.0
 )
 
 require (
@@ -18,16 +19,20 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/emicklei/go-restful/v3 v3.11.0 // indirect
 	github.com/evanphx/json-patch v5.6.0+incompatible // indirect
-	github.com/go-logr/logr v1.3.0 // indirect
+	github.com/evanphx/json-patch/v5 v5.8.0 // indirect
+	github.com/fsnotify/fsnotify v1.7.0 // indirect
+	github.com/go-logr/logr v1.4.1 // indirect
 	github.com/go-openapi/jsonpointer v0.19.6 // indirect
 	github.com/go-openapi/jsonreference v0.20.2 // indirect
 	github.com/go-openapi/swag v0.22.3 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/google/gnostic-models v0.6.8 // indirect
 	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/uuid v1.3.0 // indirect
+	github.com/imdario/mergo v0.3.6 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
@@ -40,21 +45,26 @@ require (
 	github.com/prometheus/client_model v0.5.0 // indirect
 	github.com/prometheus/common v0.45.0 // indirect
 	github.com/prometheus/procfs v0.12.0 // indirect
-	golang.org/x/net v0.17.0 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	golang.org/x/exp v0.0.0-20220722155223-a9213eeb770e // indirect
+	golang.org/x/net v0.19.0 // indirect
 	golang.org/x/oauth2 v0.12.0 // indirect
-	golang.org/x/sys v0.15.0 // indirect
-	golang.org/x/term v0.13.0 // indirect
-	golang.org/x/text v0.13.0 // indirect
+	golang.org/x/sys v0.16.0 // indirect
+	golang.org/x/term v0.15.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
 	golang.org/x/time v0.3.0 // indirect
+	gomodules.xyz/jsonpatch/v2 v2.4.0 // indirect
 	google.golang.org/appengine v1.6.7 // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
+	k8s.io/apiextensions-apiserver v0.29.0 // indirect
+	k8s.io/component-base v0.29.0 // indirect
 	k8s.io/klog/v2 v2.110.1 // indirect
 	k8s.io/kube-openapi v0.0.0-20231010175941-2dd684a91f00 // indirect
 	k8s.io/utils v0.0.0-20230726121419-3b25d923346b // indirect
 	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect
 	sigs.k8s.io/structured-merge-diff/v4 v4.4.1 // indirect
-	sigs.k8s.io/yaml v1.3.0 // indirect
+	sigs.k8s.io/yaml v1.4.0 // indirect
 )
diff --git a/go.sum b/go.sum
index f8270350..e7b4c990 100644
--- a/go.sum
+++ b/go.sum
@@ -10,8 +10,15 @@ github.com/emicklei/go-restful/v3 v3.11.0 h1:rAQeMHw1c7zTmncogyy8VvRZwtkmkZ4FxER
 github.com/emicklei/go-restful/v3 v3.11.0/go.mod h1:6n3XBCmQQb25CM2LCACGz8ukIrRry+4bhvbpWn3mrbc=
 github.com/evanphx/json-patch v5.6.0+incompatible h1:jBYDEEiFBPxA0v50tFdvOzQQTCvpL6mnFh5mB2/l16U=
 github.com/evanphx/json-patch v5.6.0+incompatible/go.mod h1:50XU6AFN0ol/bzJsmQLiYLvXMP4fmwYFNcr97nuDLSk=
-github.com/go-logr/logr v1.3.0 h1:2y3SDp0ZXuc6/cjLSZ+Q3ir+QB9T/iG5yYRXqsagWSY=
+github.com/evanphx/json-patch/v5 v5.8.0 h1:lRj6N9Nci7MvzrXuX6HFzU8XjmhPiXPlsKEy1u0KQro=
+github.com/evanphx/json-patch/v5 v5.8.0/go.mod h1:VNkHZ/282BpEyt/tObQO8s5CMPmYYq14uClGH4abBuQ=
+github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
+github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
 github.com/go-logr/logr v1.3.0/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-logr/logr v1.4.1 h1:pKouT5E8xu9zeFC39JXRDukb6JFQPXM5p5I91188VAQ=
+github.com/go-logr/logr v1.4.1/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-logr/zapr v1.3.0 h1:XGdV8XW8zdwFiwOA2Dryh1gj2KRQyOOoNmBy4EplIcQ=
+github.com/go-logr/zapr v1.3.0/go.mod h1:YKepepNBd1u/oyhd/yQmtjVXmm9uML4IXUgMOwR8/Gg=
 github.com/go-openapi/jsonpointer v0.19.6 h1:eCs3fxoIi3Wh6vtgmLTOjdhSpiqphQ+DaPn38N2ZdrE=
 github.com/go-openapi/jsonpointer v0.19.6/go.mod h1:osyAmYz/mB/C3I+WsTTSgw1ONzaLJoLCyoi6/zppojs=
 github.com/go-openapi/jsonreference v0.20.2 h1:3sVjiK66+uXK/6oQ8xgcRKcFgQ5KXa2KvnJRumpMGbE=
@@ -22,6 +29,8 @@ github.com/go-task/slim-sprig v0.0.0-20230315185526-52ccab3ef572 h1:tfuBGBXKqDEe
 github.com/go-task/slim-sprig v0.0.0-20230315185526-52ccab3ef572/go.mod h1:9Pwr4B2jHnOSGXyyzV8ROjYa2ojvAY6HCGYYfMoC3Ls=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
+github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da h1:oI5xCqsCo564l8iNU+DwB5epxmsaqB+rhGL0m5jtYqE=
+github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
 github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg=
@@ -39,6 +48,8 @@ github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1 h1:K6RDEckDVWvDI9JAJY
 github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
 github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/imdario/mergo v0.3.6 h1:xTNEAn+kxVO7dTZGu0CegyqKZmoWFI0rF8UxjlB2d28=
+github.com/imdario/mergo v0.3.6/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
 github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
 github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
@@ -63,10 +74,10 @@ github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9G
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/onsi/ginkgo/v2 v2.13.0 h1:0jY9lJquiL8fcf3M4LAXN5aMlS/b2BV86HFFPCPMgE4=
-github.com/onsi/ginkgo/v2 v2.13.0/go.mod h1:TE309ZR8s5FsKKpuB1YAQYBzCaAfUgatB/xlT/ETL/o=
-github.com/onsi/gomega v1.29.0 h1:KIA/t2t5UBzoirT4H9tsML45GEbo3ouUnBHsCfD2tVg=
-github.com/onsi/gomega v1.29.0/go.mod h1:9sxs+SwGrKI0+PWe4Fxa9tFQQBG5xSsSbMXOI8PPpoQ=
+github.com/onsi/ginkgo/v2 v2.14.0 h1:vSmGj2Z5YPb9JwCWT6z6ihcUvDhuXLc3sJiqd3jMKAY=
+github.com/onsi/ginkgo/v2 v2.14.0/go.mod h1:JkUdW7JkN0V6rFvsHcJ478egV3XH9NxpD27Hal/PhZw=
+github.com/onsi/gomega v1.30.0 h1:hvMK7xYz4D3HapigLTeGdId/NcfQx1VHMJc60ew99+8=
+github.com/onsi/gomega v1.30.0/go.mod h1:9sxs+SwGrKI0+PWe4Fxa9tFQQBG5xSsSbMXOI8PPpoQ=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -94,9 +105,17 @@ github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcU
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
+go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
+go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=
+go.uber.org/multierr v1.11.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
+go.uber.org/zap v1.26.0 h1:sI7k6L95XOKS281NhVKOFCUNIvv9e0w4BF8N3u+tCRo=
+go.uber.org/zap v1.26.0/go.mod h1:dtElttAiwGvoJ/vj4IwHBS/gXsEu/pZ50mUIRWuG0so=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/exp v0.0.0-20220722155223-a9213eeb770e h1:+WEEuIdZHnUeJJmEUjyYC2gfUMj69yZXw17EnHg/otA=
+golang.org/x/exp v0.0.0-20220722155223-a9213eeb770e/go.mod h1:Kr81I6Kryrl9sr8s2FK3vxD90NdsKWRuOIl2O4CvYbA=
 golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
@@ -104,8 +123,8 @@ golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/net v0.17.0 h1:pVaXccu2ozPjCXewfr1S7xza/zcXTity9cCdXQYSjIM=
-golang.org/x/net v0.17.0/go.mod h1:NxSsAGuq816PNPmqtQdLE42eU2Fs7NoRIZrHJAlaCOE=
+golang.org/x/net v0.19.0 h1:zTwKpTd2XuCqf8huc7Fo2iSy+4RHPd10s4KzeTnVr1c=
+golang.org/x/net v0.19.0/go.mod h1:CfAk/cbD4CthTvqiEl8NpboMuiuOYsAr/7NOjZJtv1U=
 golang.org/x/oauth2 v0.12.0 h1:smVPGxink+n1ZI5pkQa8y6fZT0RW0MgCO5bFpepy4B4=
 golang.org/x/oauth2 v0.12.0/go.mod h1:A74bZ3aGXgCY0qaIC9Ahg6Lglin4AMAco8cIv9baba4=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -114,27 +133,29 @@ golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.15.0 h1:h48lPFYpsTvQJZF4EKyI4aLHaev3CxivZmv7yZig9pc=
-golang.org/x/sys v0.15.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/term v0.13.0 h1:bb+I9cTfFazGW51MZqBVmZy7+JEJMouUHTUSKVQLBek=
-golang.org/x/term v0.13.0/go.mod h1:LTmsnFJwVN6bCy1rVCoS+qHT1HhALEFxKncY3WNNh4U=
+golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
+golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/term v0.15.0 h1:y/Oo/a/q3IXu26lQgl04j/gjuBDOBlx7X6Om1j2CPW4=
+golang.org/x/term v0.15.0/go.mod h1:BDl952bC7+uMoWR75FIrCDx79TPU9oHkTZ9yRbYOrX0=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
-golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
+golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
+golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/time v0.3.0 h1:rg5rLMjNzMS1RkNLzCG38eapWhnYLFYXDXj2gOlr8j4=
 golang.org/x/time v0.3.0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20200619180055-7c47624df98f/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
-golang.org/x/tools v0.12.0 h1:YW6HUoUmYBpwSgyaGaZq1fHjrBjX1rlpZ54T6mu2kss=
-golang.org/x/tools v0.12.0/go.mod h1:Sc0INKfu04TlqNoRA1hgpFZbhYXHPr4V5DzpSBTPqQM=
+golang.org/x/tools v0.16.1 h1:TLyB3WofjdOEepBHAU20JdNC1Zbg87elYofWYAY5oZA=
+golang.org/x/tools v0.16.1/go.mod h1:kYVVN6I1mBNoB1OX+noeBjbRk4IUEPa7JJ+TJMEooJ0=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gomodules.xyz/jsonpatch/v2 v2.4.0 h1:Ci3iUJyx9UeRx7CeFN8ARgGbkESwJK+KB9lLcWxY/Zw=
+gomodules.xyz/jsonpatch/v2 v2.4.0/go.mod h1:AH3dM2RI6uoBZxn3LVrfvJ3E0/9dG4cSrbuBJT4moAY=
 google.golang.org/appengine v1.6.7 h1:FZR1q0exgwxzPzp/aF+VccGrSfxfPpkBqjIIEq3ru6c=
 google.golang.org/appengine v1.6.7/go.mod h1:8WjMMxjGQR8xUklV/ARdw2HLXBOI7O7uCIDZVag1xfc=
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
@@ -154,19 +175,25 @@ gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 k8s.io/api v0.29.0 h1:NiCdQMY1QOp1H8lfRyeEf8eOwV6+0xA6XEE44ohDX2A=
 k8s.io/api v0.29.0/go.mod h1:sdVmXoz2Bo/cb77Pxi71IPTSErEW32xa4aXwKH7gfBA=
+k8s.io/apiextensions-apiserver v0.29.0 h1:0VuspFG7Hj+SxyF/Z/2T0uFbI5gb5LRgEyUVE3Q4lV0=
+k8s.io/apiextensions-apiserver v0.29.0/go.mod h1:TKmpy3bTS0mr9pylH0nOt/QzQRrW7/h7yLdRForMZwc=
 k8s.io/apimachinery v0.29.0 h1:+ACVktwyicPz0oc6MTMLwa2Pw3ouLAfAon1wPLtG48o=
 k8s.io/apimachinery v0.29.0/go.mod h1:eVBxQ/cwiJxH58eK/jd/vAk4mrxmVlnpBH5J2GbMeis=
 k8s.io/client-go v0.29.0 h1:KmlDtFcrdUzOYrBhXHgKw5ycWzc3ryPX5mQe0SkG3y8=
 k8s.io/client-go v0.29.0/go.mod h1:yLkXH4HKMAywcrD82KMSmfYg2DlE8mepPR4JGSo5n38=
+k8s.io/component-base v0.29.0 h1:T7rjd5wvLnPBV1vC4zWd/iWRbV8Mdxs+nGaoaFzGw3s=
+k8s.io/component-base v0.29.0/go.mod h1:sADonFTQ9Zc9yFLghpDpmNXEdHyQmFIGbiuZbqAXQ1M=
 k8s.io/klog/v2 v2.110.1 h1:U/Af64HJf7FcwMcXyKm2RPM22WZzyR7OSpYj5tg3cL0=
 k8s.io/klog/v2 v2.110.1/go.mod h1:YGtd1984u+GgbuZ7e08/yBuAfKLSO0+uR1Fhi6ExXjo=
 k8s.io/kube-openapi v0.0.0-20231010175941-2dd684a91f00 h1:aVUu9fTY98ivBPKR9Y5w/AuzbMm96cd3YHRTU83I780=
 k8s.io/kube-openapi v0.0.0-20231010175941-2dd684a91f00/go.mod h1:AsvuZPBlUDVuCdzJ87iajxtXuR9oktsTctW/R9wwouA=
 k8s.io/utils v0.0.0-20230726121419-3b25d923346b h1:sgn3ZU783SCgtaSJjpcVVlRqd6GSnlTLKgpAAttJvpI=
 k8s.io/utils v0.0.0-20230726121419-3b25d923346b/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
+sigs.k8s.io/controller-runtime v0.17.0 h1:fjJQf8Ukya+VjogLO6/bNX9HE6Y2xpsO5+fyS26ur/s=
+sigs.k8s.io/controller-runtime v0.17.0/go.mod h1:+MngTvIQQQhfXtwfdGw/UOQ/aIaqsYywfCINOtwMO/s=
 sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd h1:EDPBXCAspyGV4jQlpZSudPeMmr1bNJefnuqLsRAsHZo=
 sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd/go.mod h1:B8JuhiUyNFVKdsE8h686QcCxMaH6HrOAZj4vswFpcB0=
 sigs.k8s.io/structured-merge-diff/v4 v4.4.1 h1:150L+0vs/8DA78h1u02ooW1/fFq/Lwr+sGiqlzvrtq4=
 sigs.k8s.io/structured-merge-diff/v4 v4.4.1/go.mod h1:N8hJocpFajUSSeSJ9bOZ77VzejKZaXsTtZo4/u7Io08=
-sigs.k8s.io/yaml v1.3.0 h1:a2VclLzOGrwOHDiV8EfBGhvjHvP46CtW5j6POvhYGGo=
-sigs.k8s.io/yaml v1.3.0/go.mod h1:GeOyir5tyXNByN85N/dRIT9es5UQNerPYEKK56eTBm8=
+sigs.k8s.io/yaml v1.4.0 h1:Mk1wCc2gy/F0THH0TAp1QYyJNzRm2KCLy3o5ASXVI5E=
+sigs.k8s.io/yaml v1.4.0/go.mod h1:Ejl7/uTz7PSA4eKMyQCUTnhZYNmLIl+5c2lQPGR2BPY=
diff --git a/internal/kubediscovery/kubediscovery.go b/internal/kubediscovery/kubediscovery.go
deleted file mode 100644
index c36af220..00000000
--- a/internal/kubediscovery/kubediscovery.go
+++ /dev/null
@@ -1,106 +0,0 @@
-// Package kubediscovery implements a discovery mechanism to find other k8s resources.
-package kubediscovery
-
-import (
-	"context"
-	"fmt"
-
-	v1 "k8s.io/api/core/v1"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-
-	"k8s.io/client-go/kubernetes"
-)
-
-// Client provides the kubediscovery client methods.
-type Client struct {
-	k8s                kubernetes.Interface
-	nodeCache          *nodeCache
-	allowUnschedulable bool
-}
-
-// NodeSchedulability determines if the kubernetes node is in schedulable mode
-// or not.
-type NodeSchedulability string
-
-// Constants to define the NodeSchedulability of kubernetes Nodes
-const (
-	NodeSchedulabilityUnknown NodeSchedulability = "Unknown"
-	NodeSchedulable           NodeSchedulability = "Schedulable"
-	NodeUnschedulable         NodeSchedulability = "Unschedulable"
-)
-
-// Neighbour represents a kubenurse which should be reachable
-type Neighbour struct {
-	PodName         string
-	PodIP           string
-	HostIP          string
-	NodeName        string
-	NodeSchedulable NodeSchedulability
-	Phase           v1.PodPhase
-	Terminating     bool
-}
-
-// New creates a new kubediscovery client. The context is used to stop the k8s watchers/informers.
-// When allowUnschedulable is true, no node watcher is created and kubenurses
-// on unschedulable nodes are considered as neighbours.
-func New(ctx context.Context, cliset kubernetes.Interface, allowUnschedulable bool) (*Client, error) {
-	var (
-		nc  *nodeCache
-		err error
-	)
-
-	// Watch nodes only if we do not consider kubenurses on unschedulable nodes
-	if !allowUnschedulable {
-		nc, err = watchNodes(ctx, cliset)
-		if err != nil {
-			return nil, fmt.Errorf("starting node watcher: %w", err)
-		}
-	}
-
-	return &Client{
-		k8s:                cliset,
-		nodeCache:          nc,
-		allowUnschedulable: allowUnschedulable,
-	}, nil
-}
-
-// GetNeighbours returns a slice of neighbour kubenurses for the given namespace and labelSelector.
-func (c *Client) GetNeighbours(ctx context.Context, namespace, labelSelector string) ([]Neighbour, error) {
-	// Get all pods
-	pods, err := c.k8s.CoreV1().Pods(namespace).List(ctx, metav1.ListOptions{
-		LabelSelector: labelSelector,
-	})
-	if err != nil {
-		return nil, fmt.Errorf("list pods: %w", err)
-	}
-
-	var neighbours = make([]Neighbour, len(pods.Items))
-
-	// process pods
-	for idx := range pods.Items {
-		pod := pods.Items[idx]
-
-		// If we allow unschedulable kubenurses, we set the schedulability
-		// to unknown in order not to have to set up a node watcher.
-		sched := NodeSchedulabilityUnknown
-		if !c.allowUnschedulable {
-			sched = NodeUnschedulable
-			if c.nodeCache.isSchedulable(pod.Spec.NodeName) {
-				sched = NodeSchedulable
-			}
-		}
-
-		n := Neighbour{
-			PodName:         pod.Name,
-			PodIP:           pod.Status.PodIP,
-			HostIP:          pod.Status.HostIP,
-			Phase:           pod.Status.Phase,
-			NodeName:        pod.Spec.NodeName,
-			Terminating:     pod.DeletionTimestamp != nil,
-			NodeSchedulable: sched,
-		}
-		neighbours[idx] = n
-	}
-
-	return neighbours, nil
-}
diff --git a/internal/kubediscovery/kubediscovery_test.go b/internal/kubediscovery/kubediscovery_test.go
deleted file mode 100644
index 64a91b90..00000000
--- a/internal/kubediscovery/kubediscovery_test.go
+++ /dev/null
@@ -1,55 +0,0 @@
-package kubediscovery
-
-import (
-	"context"
-	"testing"
-
-	"github.com/stretchr/testify/require"
-	v1 "k8s.io/api/core/v1"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/kubernetes/fake"
-)
-
-var (
-	kubenursePod = v1.Pod{
-		ObjectMeta: metav1.ObjectMeta{
-			Name: "kubenurse-dummy",
-			Labels: map[string]string{
-				"app": "kubenurse",
-			},
-		},
-	}
-	differentPod = v1.Pod{
-		ObjectMeta: metav1.ObjectMeta{
-			Name: "different",
-			Labels: map[string]string{
-				"app": "different",
-			},
-		},
-	}
-)
-
-func TestGetNeighbours(t *testing.T) {
-	r := require.New(t)
-	fakeClient := fake.NewSimpleClientset()
-
-	createFakePods(fakeClient)
-
-	client, err := New(context.Background(), fakeClient, false)
-	r.NoError(err)
-
-	neighbours, err := client.GetNeighbours(context.Background(), "kube-system", "app=kubenurse")
-	r.NoError(err)
-	r.Len(neighbours, 1)
-	r.Equal(kubenursePod.ObjectMeta.Name, neighbours[0].PodName)
-}
-
-func createFakePods(k8s kubernetes.Interface) {
-	for _, pod := range []v1.Pod{kubenursePod, differentPod} {
-		_, err := k8s.CoreV1().Pods("kube-system").Create(context.Background(), &pod, metav1.CreateOptions{})
-		if err != nil {
-			panic(err)
-		}
-	}
-}
diff --git a/internal/kubediscovery/nodewatcher.go b/internal/kubediscovery/nodewatcher.go
deleted file mode 100644
index 7280558a..00000000
--- a/internal/kubediscovery/nodewatcher.go
+++ /dev/null
@@ -1,82 +0,0 @@
-package kubediscovery
-
-import (
-	"context"
-	"fmt"
-	"sync"
-	"time"
-
-	corev1 "k8s.io/api/core/v1"
-	"k8s.io/client-go/informers"
-	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/tools/cache"
-)
-
-const (
-	resyncPeriod = time.Hour * 1
-)
-
-type nodeCache struct {
-	nodes map[string]bool
-	mu    *sync.RWMutex
-}
-
-// watchNodes starts an informer to watch v1.Node resource, the context can be used to stop the informer
-func watchNodes(ctx context.Context, client kubernetes.Interface) (*nodeCache, error) {
-	nc := nodeCache{
-		nodes: make(map[string]bool),
-		mu:    new(sync.RWMutex),
-	}
-
-	informer := informers.NewSharedInformerFactory(client, resyncPeriod).Core().V1().Nodes().Informer()
-
-	_, err := informer.AddEventHandler(
-		cache.ResourceEventHandlerFuncs{
-			AddFunc:    nc.add,
-			UpdateFunc: nc.update,
-			DeleteFunc: nc.delete,
-		},
-	)
-	if err != nil {
-		return nil, fmt.Errorf("cannot add event handler for watching nodes: %w", err)
-	}
-
-	go informer.Run(ctx.Done())
-
-	if ok := cache.WaitForCacheSync(ctx.Done(), informer.HasSynced); !ok {
-		return nil, fmt.Errorf("watching nodes: initial cache sync not successful")
-	}
-
-	return &nc, nil
-}
-
-func (nc *nodeCache) add(obj interface{}) {
-	node := obj.(*corev1.Node)
-
-	nc.mu.Lock()
-	nc.nodes[node.Name] = node.Spec.Unschedulable
-	nc.mu.Unlock()
-}
-
-func (nc *nodeCache) delete(obj interface{}) {
-	node := obj.(*corev1.Node)
-
-	nc.mu.Lock()
-	delete(nc.nodes, node.Name)
-	nc.mu.Unlock()
-}
-
-func (nc *nodeCache) update(_, obj interface{}) {
-	node := obj.(*corev1.Node)
-
-	nc.mu.Lock()
-	nc.nodes[node.Name] = node.Spec.Unschedulable
-	nc.mu.Unlock()
-}
-
-func (nc *nodeCache) isSchedulable(node string) bool {
-	nc.mu.RLock()
-	defer nc.mu.RUnlock()
-
-	return !nc.nodes[node]
-}
diff --git a/internal/kubediscovery/nodewatcher_test.go b/internal/kubediscovery/nodewatcher_test.go
deleted file mode 100644
index 58a8053e..00000000
--- a/internal/kubediscovery/nodewatcher_test.go
+++ /dev/null
@@ -1,45 +0,0 @@
-package kubediscovery
-
-import (
-	"context"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/require"
-	corev1 "k8s.io/api/core/v1"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/client-go/kubernetes/fake"
-)
-
-func TestNodeWatcher(t *testing.T) {
-	node := &corev1.Node{}
-	node.Name = "testnode"
-	node.Spec.Unschedulable = false
-
-	r := require.New(t)
-	fakeClient := fake.NewSimpleClientset()
-
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	// start the informer
-	nc, err := watchNodes(ctx, fakeClient)
-	r.NoError(err)
-	r.NotNil(nc)
-
-	_, err = fakeClient.CoreV1().Nodes().Create(ctx, node, metav1.CreateOptions{})
-	r.NoError(err)
-	r.True(nc.isSchedulable(node.Name), "node is schedulable")
-
-	node.Spec.Unschedulable = true
-
-	_, err = fakeClient.CoreV1().Nodes().Update(ctx, node, metav1.UpdateOptions{})
-	r.NoError(err)
-	time.Sleep(100 * time.Millisecond) // the informer needs some time...
-	r.False(nc.isSchedulable(node.Name), "node is not schedulable")
-
-	err = fakeClient.CoreV1().Nodes().Delete(ctx, node.Name, metav1.DeleteOptions{})
-	r.NoError(err)
-
-	r.True(nc.isSchedulable("unknown"), "node not in cache")
-}
diff --git a/internal/kubenurse/handler.go b/internal/kubenurse/handler.go
index 9a1ef0d9..0b95ba70 100644
--- a/internal/kubenurse/handler.go
+++ b/internal/kubenurse/handler.go
@@ -5,7 +5,6 @@ import (
 	"net/http"
 	"os"
 
-	"github.com/postfinance/kubenurse/internal/kubediscovery"
 	"github.com/postfinance/kubenurse/internal/servicecheck"
 )
 
@@ -35,8 +34,8 @@ func (s *Server) aliveHandler() func(w http.ResponseWriter, r *http.Request) {
 			servicecheck.Result
 
 			// kubediscovery
-			NeighbourhoodState string                    `json:"neighbourhood_state"`
-			Neighbourhood      []kubediscovery.Neighbour `json:"neighbourhood"`
+			NeighbourhoodState string                   `json:"neighbourhood_state"`
+			Neighbourhood      []servicecheck.Neighbour `json:"neighbourhood"`
 		}
 
 		// Run checks now
diff --git a/internal/kubenurse/handler_test.go b/internal/kubenurse/handler_test.go
index 5bf65092..c459b0cc 100644
--- a/internal/kubenurse/handler_test.go
+++ b/internal/kubenurse/handler_test.go
@@ -7,15 +7,15 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
-	"k8s.io/client-go/kubernetes/fake"
+	"sigs.k8s.io/controller-runtime/pkg/client/fake"
 )
 
 func TestServerHandler(t *testing.T) {
 	r := require.New(t)
 
-	fakeClient := fake.NewSimpleClientset()
-
+	fakeClient := fake.NewFakeClient()
 	kubenurse, err := New(context.Background(), fakeClient)
+
 	r.NoError(err)
 	r.NotNil(kubenurse)
 
diff --git a/internal/kubenurse/k8s-auth.go b/internal/kubenurse/k8s-auth.go
new file mode 100644
index 00000000..c51b51cb
--- /dev/null
+++ b/internal/kubenurse/k8s-auth.go
@@ -0,0 +1,7 @@
+//go:build debug
+
+package kubenurse
+
+import (
+	_ "k8s.io/client-go/plugin/pkg/client/auth" // permits to use all authentication providers
+)
diff --git a/internal/kubenurse/server.go b/internal/kubenurse/server.go
index 516a0ca6..f85a927a 100644
--- a/internal/kubenurse/server.go
+++ b/internal/kubenurse/server.go
@@ -12,12 +12,11 @@ import (
 	"sync"
 	"time"
 
-	"github.com/postfinance/kubenurse/internal/kubediscovery"
 	"github.com/postfinance/kubenurse/internal/servicecheck"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/collectors"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"k8s.io/client-go/kubernetes"
+	"sigs.k8s.io/controller-runtime/pkg/client"
 )
 
 const defaultCheckInterval = 5 * time.Second
@@ -56,7 +55,7 @@ type Server struct {
 // * KUBENURSE_CHECK_ME_SERVICE
 // * KUBENURSE_CHECK_NEIGHBOURHOOD
 // * KUBENURSE_CHECK_INTERVAL
-func New(ctx context.Context, k8s kubernetes.Interface) (*Server, error) { //nolint:funlen // TODO: use a flag parsing library (e.g. ff) to reduce complexity
+func New(ctx context.Context, c client.Client) (*Server, error) { //nolint:funlen // TODO: use a flag parsing library (e.g. ff) to reduce complexity
 	mux := http.NewServeMux()
 
 	checkInterval := defaultCheckInterval
@@ -100,11 +99,6 @@ func New(ctx context.Context, k8s kubernetes.Interface) (*Server, error) { //nol
 		collectors.NewProcessCollector(collectors.ProcessCollectorOpts{}),
 	)
 
-	discovery, err := kubediscovery.New(ctx, k8s, server.allowUnschedulable)
-	if err != nil {
-		return nil, fmt.Errorf("create k8s discovery client: %w", err)
-	}
-
 	var histogramBuckets []float64
 
 	if bucketsString := os.Getenv("KUBENURSE_HISTOGRAM_BUCKETS"); bucketsString != "" {
@@ -124,7 +118,7 @@ func New(ctx context.Context, k8s kubernetes.Interface) (*Server, error) { //nol
 	}
 
 	// setup checker
-	chk, err := servicecheck.New(ctx, discovery, promRegistry, server.allowUnschedulable, 3*time.Second, histogramBuckets)
+	chk, err := servicecheck.New(ctx, c, promRegistry, server.allowUnschedulable, 3*time.Second, histogramBuckets)
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/kubenurse/server_test.go b/internal/kubenurse/server_test.go
index b45d47c7..5e38c1a0 100644
--- a/internal/kubenurse/server_test.go
+++ b/internal/kubenurse/server_test.go
@@ -5,14 +5,13 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
-	"k8s.io/client-go/kubernetes/fake"
+	"sigs.k8s.io/controller-runtime/pkg/client/fake"
 )
 
 func TestCombined(t *testing.T) {
 	r := require.New(t)
 
-	fakeClient := fake.NewSimpleClientset()
-
+	fakeClient := fake.NewFakeClient()
 	kubenurse, err := New(context.Background(), fakeClient)
 	r.NoError(err)
 	r.NotNil(kubenurse)
diff --git a/internal/servicecheck/neighbours.go b/internal/servicecheck/neighbours.go
new file mode 100644
index 00000000..4d24fd98
--- /dev/null
+++ b/internal/servicecheck/neighbours.go
@@ -0,0 +1,83 @@
+package servicecheck
+
+import (
+	"context"
+	"fmt"
+
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/types"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+// Neighbour represents a kubenurse which should be reachable
+type Neighbour struct {
+	PodName  string
+	PodIP    string
+	HostIP   string
+	NodeName string
+}
+
+// GetNeighbours returns a slice of neighbour kubenurses for the given namespace and labelSelector.
+func (c *Checker) GetNeighbours(ctx context.Context, namespace, labelSelector string) ([]Neighbour, error) {
+	// Get all pods
+	pods := v1.PodList{}
+	selector, _ := labels.Parse(labelSelector)
+	err := c.client.List(ctx, &pods, &client.ListOptions{
+		LabelSelector: selector,
+		Namespace:     namespace,
+	})
+
+	if err != nil {
+		return nil, fmt.Errorf("list pods: %w", err)
+	}
+
+	var neighbours = make([]Neighbour, 0, len(pods.Items))
+
+	// process pods
+	for idx := range pods.Items {
+		pod := pods.Items[idx]
+
+		if !c.allowUnschedulable { // if we disallow unschedulable nodes, we have to check their status
+			n := v1.Node{}
+			if err := c.client.Get(ctx, types.NamespacedName{Name: pod.Spec.NodeName}, &n); err == nil {
+				if n.Spec.Unschedulable { // node unschedulable, we do not include this pod in the neighbour list
+					continue
+				}
+			}
+		}
+
+		if pod.Status.Phase != v1.PodRunning || // only query running pods (excludes pending ones)
+			pod.DeletionTimestamp != nil { // exclude terminating pods
+			continue
+		}
+
+		n := Neighbour{
+			PodName:  pod.Name,
+			PodIP:    pod.Status.PodIP,
+			HostIP:   pod.Status.HostIP,
+			NodeName: pod.Spec.NodeName,
+		}
+		neighbours = append(neighbours, n)
+	}
+
+	return neighbours, nil
+}
+
+// checkNeighbours checks the /alwayshappy endpoint from every discovered kubenurse neighbour. Neighbour pods on nodes
+// which are not schedulable are excluded from this check to avoid possible false errors.
+func (c *Checker) checkNeighbours(nh []Neighbour) {
+	for _, neighbour := range nh {
+		neighbour := neighbour // pin
+
+		check := func(ctx context.Context) (string, error) {
+			if c.UseTLS {
+				return c.doRequest(ctx, "https://"+neighbour.PodIP+":8443/alwayshappy")
+			}
+
+			return c.doRequest(ctx, "http://"+neighbour.PodIP+":8080/alwayshappy")
+		}
+
+		_, _ = c.measure(check, "path_"+neighbour.NodeName)
+	}
+}
diff --git a/internal/servicecheck/servicecheck.go b/internal/servicecheck/servicecheck.go
index f5698e72..7178513f 100644
--- a/internal/servicecheck/servicecheck.go
+++ b/internal/servicecheck/servicecheck.go
@@ -11,9 +11,8 @@ import (
 	"os"
 	"time"
 
-	"github.com/postfinance/kubenurse/internal/kubediscovery"
 	"github.com/prometheus/client_golang/prometheus"
-	v1 "k8s.io/api/core/v1"
+	"sigs.k8s.io/controller-runtime/pkg/client"
 )
 
 const (
@@ -25,7 +24,7 @@ const (
 
 // New configures the checker with a httpClient and a cache timeout for check
 // results. Other parameters of the Checker struct need to be configured separately.
-func New(_ context.Context, discovery *kubediscovery.Client, promRegistry *prometheus.Registry,
+func New(_ context.Context, cl client.Client, promRegistry *prometheus.Registry,
 	allowUnschedulable bool, cacheTTL time.Duration, durationHistogramBuckets []float64) (*Checker, error) {
 	errorCounter := prometheus.NewCounterVec(
 		prometheus.CounterOpts{
@@ -80,7 +79,7 @@ func New(_ context.Context, discovery *kubediscovery.Client, promRegistry *prome
 
 	return &Checker{
 		allowUnschedulable: allowUnschedulable,
-		discovery:          discovery,
+		client:             cl,
 		httpClient:         httpClient,
 		cacheTTL:           cacheTTL,
 		errorCounter:       errorCounter,
@@ -121,7 +120,7 @@ func (c *Checker) Run() (Result, bool) {
 	if c.SkipCheckNeighbourhood {
 		res.NeighbourhoodState = skippedStr
 	} else {
-		res.Neighbourhood, err = c.discovery.GetNeighbours(context.TODO(), c.KubenurseNamespace, c.NeighbourFilter)
+		res.Neighbourhood, err = c.GetNeighbours(context.TODO(), c.KubenurseNamespace, c.NeighbourFilter)
 		haserr = haserr || (err != nil)
 
 		// Neighbourhood special error treating
@@ -202,27 +201,6 @@ func (c *Checker) MeService(ctx context.Context) (string, error) {
 	return c.doRequest(ctx, c.KubenurseServiceURL+"/alwayshappy")
 }
 
-// checkNeighbours checks the /alwayshappy endpoint from every discovered kubenurse neighbour. Neighbour pods on nodes
-// which are not schedulable are excluded from this check to avoid possible false errors.
-func (c *Checker) checkNeighbours(nh []kubediscovery.Neighbour) {
-	for _, neighbour := range nh {
-		neighbour := neighbour                 // pin
-		if neighbour.Phase == v1.PodRunning && // only query running pods (excludes pending ones)
-			!neighbour.Terminating && // exclude terminating pods
-			(c.allowUnschedulable || neighbour.NodeSchedulable == kubediscovery.NodeSchedulable) {
-			check := func(ctx context.Context) (string, error) {
-				if c.UseTLS {
-					return c.doRequest(ctx, "https://"+neighbour.PodIP+":8443/alwayshappy")
-				}
-
-				return c.doRequest(ctx, "http://"+neighbour.PodIP+":8080/alwayshappy")
-			}
-
-			_, _ = c.measure(check, "path_"+neighbour.NodeName)
-		}
-	}
-}
-
 // measure implements metric collections for the check
 func (c *Checker) measure(check Check, label string) (string, error) {
 	start := time.Now()
diff --git a/internal/servicecheck/servicecheck_test.go b/internal/servicecheck/servicecheck_test.go
index 07cf4db8..6fba11ee 100644
--- a/internal/servicecheck/servicecheck_test.go
+++ b/internal/servicecheck/servicecheck_test.go
@@ -5,17 +5,17 @@ import (
 	"testing"
 	"time"
 
-	"github.com/postfinance/kubenurse/internal/kubediscovery"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/stretchr/testify/require"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/client-go/kubernetes/fake"
+	"sigs.k8s.io/controller-runtime/pkg/client/fake"
 )
 
 var fakeNeighbourPod = v1.Pod{
 	ObjectMeta: metav1.ObjectMeta{
-		Name: "kubenurse-dummy",
+		Name:      "kubenurse-dummy",
+		Namespace: "kube-system",
 		Labels: map[string]string{
 			"app": "kubenurse",
 		},
@@ -26,6 +26,7 @@ var fakeNeighbourPod = v1.Pod{
 	Status: v1.PodStatus{
 		HostIP: "127.0.0.1",
 		PodIP:  "127.0.0.1",
+		Phase:  v1.PodRunning,
 	},
 }
 
@@ -33,14 +34,9 @@ func TestCombined(t *testing.T) {
 	r := require.New(t)
 
 	// fake client, with a dummy neighbour pod
-	fakeClient := fake.NewSimpleClientset()
-	_, err := fakeClient.CoreV1().Pods("kube-system").Create(context.Background(), &fakeNeighbourPod, metav1.CreateOptions{})
-	r.NoError(err)
-
-	discovery, err := kubediscovery.New(context.Background(), fakeClient, false)
-	r.NoError(err)
+	fakeClient := fake.NewFakeClient(&fakeNeighbourPod)
 
-	checker, err := New(context.Background(), discovery, prometheus.NewRegistry(), false, 3*time.Second, prometheus.DefBuckets)
+	checker, err := New(context.Background(), fakeClient, prometheus.NewRegistry(), false, 3*time.Second, prometheus.DefBuckets)
 	r.NoError(err)
 	r.NotNil(checker)
 
diff --git a/internal/servicecheck/types.go b/internal/servicecheck/types.go
index 47c9e758..c1d72e5e 100644
--- a/internal/servicecheck/types.go
+++ b/internal/servicecheck/types.go
@@ -5,8 +5,8 @@ import (
 	"net/http"
 	"time"
 
-	"github.com/postfinance/kubenurse/internal/kubediscovery"
 	"github.com/prometheus/client_golang/prometheus"
+	"sigs.k8s.io/controller-runtime/pkg/client"
 )
 
 // Checker implements the kubenurse checker
@@ -35,7 +35,8 @@ type Checker struct {
 	// TLS
 	UseTLS bool
 
-	discovery *kubediscovery.Client
+	// Controller runtime cached client
+	client client.Client
 
 	// metrics
 	errorCounter      *prometheus.CounterVec
@@ -56,12 +57,12 @@ type Checker struct {
 
 // Result contains the result of a performed check run
 type Result struct {
-	APIServerDirect    string                    `json:"api_server_direct"`
-	APIServerDNS       string                    `json:"api_server_dns"`
-	MeIngress          string                    `json:"me_ingress"`
-	MeService          string                    `json:"me_service"`
-	NeighbourhoodState string                    `json:"neighbourhood_state"`
-	Neighbourhood      []kubediscovery.Neighbour `json:"neighbourhood"`
+	APIServerDirect    string      `json:"api_server_direct"`
+	APIServerDNS       string      `json:"api_server_dns"`
+	MeIngress          string      `json:"me_ingress"`
+	MeService          string      `json:"me_service"`
+	NeighbourhoodState string      `json:"neighbourhood_state"`
+	Neighbourhood      []Neighbour `json:"neighbourhood"`
 }
 
 // Check is the signature used by all checks that the checker can execute.
diff --git a/main.go b/main.go
index 441ee388..f1b5055c 100644
--- a/main.go
+++ b/main.go
@@ -3,15 +3,19 @@ package main
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log"
+	"os"
 	"os/signal"
 	"syscall"
 	"time"
 
 	"github.com/postfinance/kubenurse/internal/kubenurse"
-	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/rest"
+	corev1 "k8s.io/api/core/v1"
+	controllerruntime "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/cache"
+	"sigs.k8s.io/controller-runtime/pkg/client"
 )
 
 const (
@@ -22,20 +26,48 @@ func main() {
 	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 	defer cancel()
 
-	// create in-cluster config
-	config, err := rest.InClusterConfig()
+	restConf, err := controllerruntime.GetConfig()
 	if err != nil {
-		log.Printf("creating in-cluster configuration: %s", err)
+		log.Println(err)
 		return
 	}
 
-	cliset, err := kubernetes.NewForConfig(config)
+	kubenurseNs := os.Getenv("KUBENURSE_NAMESPACE")
+
+	ca, err := cache.New(restConf, cache.Options{
+		ByObject: map[client.Object]cache.ByObject{
+			&corev1.Pod{}: {Namespaces: map[string]cache.Config{
+				kubenurseNs: {},
+			}},
+			&corev1.Node{}: {},
+		},
+	})
+
+	if err != nil {
+		log.Printf("error during cache creation: %s", err)
+		return
+	}
+
+	go func() {
+		if err = ca.Start(ctx); !errors.Is(err, context.Canceled) {
+			log.Printf("client cache error: %s", err)
+			cancel()
+		}
+	}()
+
+	opts := client.Options{
+		Cache: &client.CacheOptions{
+			Reader: ca,
+		},
+	}
+
+	c, err := client.New(restConf, opts)
 	if err != nil {
-		log.Printf("creating clientset: %s", err)
+		log.Printf("error while starting controller-runtime client: %s", err)
 		return
 	}
 
-	server, err := kubenurse.New(ctx, cliset)
+	server, err := kubenurse.New(ctx, c)
 	if err != nil {
 		log.Printf("%s", err)
 		return