Add a child page to describe kubelet configuration

Signed-off-by: Kotaro Inoue <[email protected]>

Author: musaprg

docs/book/src/tasks/bootstrap/kubeadm-bootstrap/kubelet-config.md

@@ -0,0 +1,167 @@
+# Kubelet Configuration
+
+CAPBK has several ways to configure kubelet.
+
+- [`cloud-init` files](#cloud-init-files)
+- [`kubeletExtraArgs`](#set-kubelet-flags-via-kubeletextraargs)
+- [`kubeletconfiguration` patch target](#use-the-kubeletconfiguration-patch-target)
+
+## Pass `KubeletConfiguration` file via `cloud-init` files
+
+You can use `cloud-init` files to put any files on nodes.
+
+### KubeadmControlPlaneTemplate
+
+```yaml
+apiVersion: controlplane.cluster.x-k8s.io/v1beta1
+kind: KubeadmControlPlaneTemplate
+metadata:
+  name: cloudinit-control-plane
+  namespace: default
+spec:
+  template:
+    spec:
+      kubeadmConfigSpec:
+        files:
+        - path: /etc/kubernetes/kubelet/config.yaml
+          owner: "root:root"
+          permissions: "0644"
+          content: |
+            apiVersion: kubelet.config.k8s.io/v1beta1
+            kind: KubeletConfiguration
+            evictionHard:
+              nodefs.available: "0%"
+              nodefs.inodesFree: "0%"
+              imagefs.available: "0%"
+            authentication:
+              anonymous:
+                enabled: false
+              webhook:
+                cacheTTL: 0s
+                enabled: true
+              x509:
+                clientCAFile: /etc/kubernetes/pki/ca.crt
+            authorization:
+              mode: Webhook
+              webhook:
+                cacheAuthorizedTTL: 0s
+                cacheUnauthorizedTTL: 0s
+            cgroupDriver: systemd
+            clusterDNS:
+            - 10.128.0.10
+            clusterDomain: cluster.local
+            containerRuntimeEndpoint: ""
+            cpuManagerReconcilePeriod: 0s
+            evictionPressureTransitionPeriod: 0s
+            fileCheckFrequency: 0s
+            healthzBindAddress: 127.0.0.1
+            healthzPort: 10248
+            httpCheckFrequency: 0s
+            imageMinimumGCAge: 0s
+            logging:
+              flushFrequency: 0
+              options:
+                json:
+                  infoBufferSize: "0"
+              verbosity: 0
+            memorySwap: {}
+            nodeStatusReportFrequency: 0s
+            nodeStatusUpdateFrequency: 0s
+            rotateCertificates: true
+            runtimeRequestTimeout: 0s
+            shutdownGracePeriod: 0s
+            shutdownGracePeriodCriticalPods: 0s
+            staticPodPath: /etc/kubernetes/manifests
+            streamingConnectionIdleTimeout: 0s
+            syncFrequency: 0s
+            volumeStatsAggPeriod: 0s
+        clusterConfiguration:
+          controllerManager:
+            extraArgs:
+              enable-hostpath-provisioner: "true"
+        initConfiguration:
+          nodeRegistration:
+            criSocket: unix:///var/run/containerd/containerd.sock
+            kubeletExtraArgs:
+              config: "/etc/kubernetes/kubelet/config.yaml"
+        joinConfiguration:
+          nodeRegistration:
+            criSocket: unix:///var/run/containerd/containerd.sock
+            kubeletExtraArgs:
+              config: "/etc/kubernetes/kubelet/config.yaml"
+```
+
+### KubeadmConfigTemplate
+
+```
+```
+
+## Set kubelet flags via `kubeletExtraArgs`
+
+```yaml
+apiVersion: controlplane.cluster.x-k8s.io/v1beta1
+kind: KubeadmControlPlaneTemplate
+metadata:
+  name: kubelet-extra-args-control-plane
+  namespace: default
+spec:
+  template:
+    spec:
+      kubeadmConfigSpec:
+        clusterConfiguration:
+          controllerManager:
+            extraArgs:
+              enable-hostpath-provisioner: "true"
+        initConfiguration:
+          nodeRegistration:
+            criSocket: unix:///var/run/containerd/containerd.sock
+            kubeletExtraArgs:
+              eviction-hard: nodefs.available<0%,nodefs.inodesFree<0%,imagefs.available<0%
+        joinConfiguration:
+          nodeRegistration:
+            criSocket: unix:///var/run/containerd/containerd.sock
+            kubeletExtraArgs:
+              eviction-hard: nodefs.available<0%,nodefs.inodesFree<0%,imagefs.available<0%
+```
+
+## Use the `kubeletconfiguration` patch target
+
+```yaml
+apiVersion: controlplane.cluster.x-k8s.io/v1beta1
+kind: KubeadmControlPlaneTemplate
+metadata:
+  name: kubeadm-config-template-control-plane
+  namespace: default
+spec:
+  template:
+    spec:
+      kubeadmConfigSpec:
+        files:
+        - path: /etc/kubernetes/patches/kubeletconfiguration0+strategic.json
+          owner: "root:root"
+          permissions: "0644"
+          content: |
+            {
+              "apiVersion": "kubelet.config.k8s.io/v1beta1",
+              "kind": "KubeletConfiguration",
+              "evictionHard": {
+                "nodefs.available": "0%",
+                "nodefs.inodesFree": "0%",
+                "imagefs.available": "0%",
+              },
+            }
+        clusterConfiguration:
+          controllerManager:
+            extraArgs:
+              enable-hostpath-provisioner: "true"
+        initConfiguration:
+          nodeRegistration:
+            criSocket: unix:///var/run/containerd/containerd.sock
+          patches:
+            directory: /etc/kubernetes/patches
+        joinConfiguration:
+          nodeRegistration:
+            criSocket: unix:///var/run/containerd/containerd.sock
+          patches:
+            directory: /etc/kubernetes/patches
+```