vi /etc/hosts
hostnamectl set-hostname kubehost
hostname -f


sed -i '/[[:space:]]swap[[:space:]]/ s/^[^#]/#&/' /etc/fstab
swapoff -a
swapon --show

tee /etc/modules-load.d/k8s.conf <<EOF
overlay
br_netfilter
EOF

modprobe overlay
modprobe br_netfilter

lsmod | grep -E 'br_netfilter|overlay'



tee /etc/sysctl.d/k8s.conf <<EOF
net.bridge.bridge-nf-call-iptables  = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward                 = 1
EOF

sysctl --system
sysctl net.ipv4.ip_forward net.bridge.bridge-nf-call-iptables


apt update
apt install -y containerd
mkdir -p /etc/containerd
containerd config default | tee /etc/containerd/config.toml > /dev/null
sed -i 's/SystemdCgroup = false/SystemdCgroup = true/' /etc/containerd/config.toml

systemctl edit containerd
[Service]
LimitNOFILE=1048576
LimitNOFILESoft=1048576

systemctl restart containerd
systemctl enable containerd
systemctl is-active containerd
grep 'SystemdCgroup = true' /etc/containerd/config.toml


apt install -y apt-transport-https ca-certificates curl gpg
mkdir -p -m 755 /etc/apt/keyrings
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.36/deb/Release.key | gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.36/deb/ /" | tee /etc/apt/sources.list.d/kubernetes.list
apt update
apt install -y kubelet kubeadm kubectl
apt-mark hold kubelet kubeadm kubectl


kubeadm version
kubelet --version
kubectl version --client
kubeadm init --pod-network-cidr=10.244.0.0/16

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config


kubectl get nodes
watch 'kubectl get nodes'


kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml
kubectl get pods -n kube-flannel
kubectl get pods -n kube-system
kubectl get nodes -o wide


kubectl run --image=hello-world hello-world
kubectl get pods
kubectl describe nodes | grep Taints
kubectl taint nodes --all node-role.kubernetes.io/control-plane:NoSchedule-
kubectl taint nodes --all node-role.kubernetes.io/master:NoSchedule-
kubectl get pods
kubectl delete pod/hello-world



apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: standard
provisioner: kubernetes.io/no-provisioner
volumeBindingMode: WaitForFirstConsumer




mkdir /k8sdata /k8sdata2 /k8sdata3
chmod 777 /k8sdata*
tee pv.yaml << EOF
apiVersion: v1
kind: PersistentVolume
metadata:
  name: manual-pv1
spec:
  capacity:
    storage: 30Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/k8sdata"
  storageClassName: standard
EOF
# modify for pv2 pv3
kubectl apply -f pv.yaml 
# repeat for pv2 pv3


HELM_BUILDKITE_APT_KEY_ID="DDF78C3E6EBB2D2CC223C95C62BA89D07698DBC6"
apt-get install curl gpg apt-transport-https --yes
curl -fsSL https://packages.buildkite.com/helm-linux/helm-debian/gpgkey > "${TMPDIR:-/tmp}/helm.gpg"
# Ensure that the key ID matches to prevent a repository compromise from establishing an attacker controlled key
if [ "$(gpg --show-keys --with-colons "${TMPDIR:-/tmp}/helm.gpg" | awk -F: '$1 == "fpr" {print $10}' | head -n 1)" != "${HELM_BUILDKITE_APT_KEY_ID}" ]; then echo "ERROR: Unexpected Helm APT key ID: potential key compromise"; exit 1; fi
cat "${TMPDIR:-/tmp}/helm.gpg" | gpg --dearmor | tee /usr/share/keyrings/helm.gpg > /dev/null
echo "deb [signed-by=/usr/share/keyrings/helm.gpg] https://packages.buildkite.com/helm-linux/helm-debian/any/ any main" | tee /etc/apt/sources.list.d/helm-stable-debian.list
apt-get update
apt-get install helm


helm repo add mongodb https://mongodb.github.io/helm-charts
helm install kubernetes-operator mongodb/mongodb-kubernetes --namespace mongodb --create-namespace
# Other than namespace, other values are specified with --set param.child=value
# See: https://www.mongodb.com/docs/kubernetes/current/reference/helm-operator-settings/
kubectl config get-contexts
kubectl config set-context $(kubectl config current-context) --namespace=mongodb
kubectl create secret generic ops-manager-admin-secret   --from-literal=Username="dba"   --from-literal=Password="ChangeMe123%"   --from-literal=FirstName="dba"   --from-literal=LastName="dba"


tee ops-manager.yaml <<EOF
apiVersion: mongodb.com/v1
kind: MongoDBOpsManager
metadata:
  name: ops-manager
  namespace: mongodb
spec:
  replicas: 1
  version: "8.0.27"
  adminCredentials: ops-manager-admin-secret
  externalConnectivity:
    type: NodePort
  configuration:
    mms.ignoreInitialUiSetup: "true"
    automation.versions.source: "mongodb"
    mms.fromEmailAddr: admin@example.com
    mms.replyToEmailAddr: admin@example.com
    mms.adminEmailAddr: admin@example.com
    mms.mail.transport: smtp
    mms.mail.hostname: localhost
    mms.mail.port: "25"
  backup:
    enabled: false
  applicationDatabase:
    topology: SingleCluster
    members: 3
    version: "8.0.32-ent"
    podSpec:
      persistence:
        single:
          storageClass: standard
          storage: 20Gi
EOF


# tee ops-manager.yaml <<EOF
# apiVersion: mongodb.com/v1
# kind: MongoDBOpsManager
# metadata:
#   name: opsmanager
# spec:
#   replicas: 1
#   version: 8.0.27
#   adminCredentials: ops-manager-admin-secret
#   externalConnectivity:
#     type: NodePort
#   applicationDatabase:
#     topology: SingleCluster
#     members: 3
#     version: 8.0.32-ubi8
#     podSpec:
#       podTemplate:
#         spec:
#           containers:
#             - name: mongodb-enterprise-database
#               imagePullPolicy: Always
#             - name: mongodb-agent
#               imagePullPolicy: Always
#   backup:
#     enabled: false
# EOF
# kubectl apply -f ops-manager.yaml
# kubectl get om -o yaml -w


kubectl describe pods/ops-manager-db-0
kubectl get om -o yaml -w
kubectl get om -o yaml
kubectl describe pods/ops-manager-db-0
vi ops-manager.yaml 
kubectl describe pods/ops-manager-db-0
kubectl exec -it ops-manager-db-0 -- /bin/bash
kubectl logs ops-manager-db-0
kubectl get pods
kubectl logs mongodb-kubernetes-operator-784795fb96-4rp5s
kubectl get pods/ops-manager-db-0 -o jsonpath='{.spec.containers[*].name}'
kubectl exec -it -c mongod ops-manager-db-0 -- /bin/bash
kubectl exec -it -c mongod ops-manager-db-0 -- /bin/bash
kubectl exec -it -c mongod -u 0 ops-manager-db-0 -- /bin/bash
kubectl exec -it -c mongod ops-manager-db-0 -- /bin/bash
kubectl get nodes
kubectl describe nodes
kubectl get pvcs
kubectl get pvc
kubectl describe pvc
kubectl get pv
ls
cat pv.yaml 
cp pv.yaml pv2.yaml
vi pv2.yaml 
mkdir /k8sdata2
chmod 777 /k8sdata2
vi pv2.yaml 
kubectl apply -f pv2.yaml 
kubectl get pv
kubectl get pvc
mkdir /k8sdata3
chmod 777 /k8sdata3
cp pv2.yaml pv3.yaml
vi pv3.yaml
kubectl apply -f pv3.yaml 
kubectl get pods -w
kubectl get om -o yaml -w
kubectl get pods
kubectl delete pods/ops-manager-db-0
kubectl get sts
kubectl describe sts
kubectl get pvc
kubectl get pv
kubectl get events
kubectl get pods
kubectl get om -o yaml -w
kubectl get sts
kubectl get pods
kubectl logs ops-manager-db-1
kubectl describe pods
kubectl get all
kubectl logs pod/ops-manager-db-2
kubectl describe pod/ops-manager-db-2
kubectl get storageclass
cat > storclas.yaml
kubectl apply -f storclas.yaml 
kubectl describe pod/ops-manager-db-2
kubectl get storageclass
kubectl describe storageclass
kubectl get pods
init 0
shutdown -h now
kubectl get nodes
history


# krew plugin



---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: private-registry
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: private-registry
  template:
    metadata:
      labels:
        app: private-registry
    spec:
      containers:
        - name: registry
          image: registry:2
          ports:
            - containerPort: 5000
          volumeMounts:
            - name: registry-storage
              mountPath: /var/lib/registry
      volumes:
        - name: registry-storage
          emptyDir: {}

#          hostPath:
#            path: /mnt/vpath

#          persistentVolumeClaim:
#            claimName: clm1



---
apiVersion: v1
kind: Service
metadata:
  name: private-registry
  namespace: default
spec:
  selector:
    app: private-registry
  ports:
    - protocol: TCP
      port: 5000
      targetPort: 5000


---
apiVersion: v1
kind: Service
metadata:
  name: ext-private-registry
  namespace: default
spec:
  type: NodePort
  selector:
    app: private-registry
  ports:
    - port: 5000
      targetPort: 5000
      nodePort: 30050