Add basic scripts to configure kuberntes cluster

docs/08-scheduler.md

@@ -0,0 +1,149 @@
+# Scheduler
+
+![image](./img/08_cluster_architecture_scheduler.png "Kubelet")
+
+```bash
+{
+
+cat > kube-scheduler-csr.json <<EOF
+{
+  "CN": "system:kube-scheduler",
+  "key": {
+    "algo": "rsa",
+    "size": 2048
+  },
+  "names": [
+    {
+      "C": "US",
+      "L": "Portland",
+      "O": "system:kube-scheduler",
+      "OU": "Kubernetes The Hard Way",
+      "ST": "Oregon"
+    }
+  ]
+}
+EOF
+
+cfssl gencert \
+  -ca=ca.pem \
+  -ca-key=ca-key.pem \
+  -config=ca-config.json \
+  -profile=kubernetes \
+  kube-scheduler-csr.json | cfssljson -bare kube-scheduler
+
+}
+```
+
+```bash
+{
+  kubectl config set-cluster kubernetes-the-hard-way \
+    --certificate-authority=ca.pem \
+    --embed-certs=true \
+    --server=https://127.0.0.1:6443 \
+    --kubeconfig=kube-scheduler.kubeconfig
+
+  kubectl config set-credentials system:kube-scheduler \
+    --client-certificate=kube-scheduler.pem \
+    --client-key=kube-scheduler-key.pem \
+    --embed-certs=true \
+    --kubeconfig=kube-scheduler.kubeconfig
+
+  kubectl config set-context default \
+    --cluster=kubernetes-the-hard-way \
+    --user=system:kube-scheduler \
+    --kubeconfig=kube-scheduler.kubeconfig
+
+  kubectl config use-context default --kubeconfig=kube-scheduler.kubeconfig
+}
+```
+
+```bash
+wget -q --show-progress --https-only --timestamping \
+  "https://storage.googleapis.com/kubernetes-release/release/v1.21.0/bin/linux/amd64/kube-scheduler"
+```
+
+```bash
+{
+  chmod +x kube-scheduler
+  sudo mv kube-scheduler /usr/local/bin/
+}
+```
+
+
+```bash
+sudo mv kube-scheduler.kubeconfig /var/lib/kubernetes/
+```
+
+```bash
+cat <<EOF | sudo tee /etc/kubernetes/config/kube-scheduler.yaml
+apiVersion: kubescheduler.config.k8s.io/v1beta1
+kind: KubeSchedulerConfiguration
+clientConnection:
+  kubeconfig: "/var/lib/kubernetes/kube-scheduler.kubeconfig"
+leaderElection:
+  leaderElect: true
+EOF
+```
+
+```bash
+cat <<EOF | sudo tee /etc/systemd/system/kube-scheduler.service
+[Unit]
+Description=Kubernetes Scheduler
+Documentation=https://github.com/kubernetes/kubernetes
+
+[Service]
+ExecStart=/usr/local/bin/kube-scheduler \\
+  --config=/etc/kubernetes/config/kube-scheduler.yaml \\
+  --v=2
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
+EOF
+```
+
+```bash
+{
+  sudo systemctl daemon-reload
+  sudo systemctl enable kube-scheduler
+  sudo systemctl start kube-scheduler
+}
+```
+
+```bash
+sudo systemctl status kube-scheduler
+```
+
+```
+● kube-scheduler.service - Kubernetes Scheduler
+     Loaded: loaded (/etc/systemd/system/kube-scheduler.service; enabled; vendor preset: enabled)
+     Active: active (running) since Thu 2023-04-20 11:57:44 UTC; 16s ago
+       Docs: https://github.com/kubernetes/kubernetes
+   Main PID: 15134 (kube-scheduler)
+      Tasks: 7 (limit: 2275)
+     Memory: 13.7M
+     CGroup: /system.slice/kube-scheduler.service
+             └─15134 /usr/local/bin/kube-scheduler --config=/etc/kubernetes/config/kube-scheduler.yaml --v=2
+...
+```
+
+```bash
+kubectl get pod -o wide
+```
+
+```
+hello-world                         1/1     Running   0          35m     10.240.1.9    example-server   <none>           <none>
+nginx-deployment-5d9cbcf759-x4pk8   1/1     Running   0          9m34s   10.240.1.10   example-server   <none>           <none>
+```
+
+```bash
+kubectl logs nginx-deployment-5d9cbcf759-x4pk8
+```
+
+```
+Hello, World from deployment!
+Hello, World from deployment!
+Hello, World from deployment!
+...
+```