kubernetes tutorial | Install K8s Cluster using kubeadm | Deploy a 3 node K8s cluster using kubeadm
CERTIFIED KUBERNETES ADMINISTRATOR
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USEFUL LINKS
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Install Kubeadm
https://kubernetes.io/docs/setup/prod...
Container Runtimes
https://kubernetes.io/docs/setup/prod...
Install Docker CRI
https://docs.docker.com/engine/instal...
Deploy a Kubernetes Cluster
https://kubernetes.io/docs/setup/prod...
POD NETWORKING
https://kubernetes.io/docs/setup/prod...
https://kubernetes.io/docs/concepts/c...
(Weavenet CNI Plugin)
https://www.weave.works/docs/net/late...
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#cka #kubernetes #k8s #containers
DEMO STEPS
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Step 1: Pre-requisites
1.a.. Check the OS, Hardware Configurations & Network connectivity
1.b.. Turn off the swap & firewall
$ sudo swapoff -a
$ sudo systemctl stop firewalld
$ sudo systemctl disable firewalld
Step 2. Configure the local IP tables to see the Bridged Traffic
2.a.. Enable the bridged traffic
$ lsmod | grep br_netfilter
$ sudo modprobe br_netfilter
2.b.. Copy the below contents in this file.. /etc/modules-load.d/k8s.conf
Content:
br_netfilter
2.c.. Copy the below contents in this file.. /etc/sysctl.d/k8s.conf
Content:
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
$ sudo sysctl --system
Step 3. Install Docker as a Container RUNTIME
3.a.. Uninstall any Older versions
$ sudo yum remove docker docker-client docker-client-latest docker-common docker-latest docker-latest-logrotate docker-logrotate docker-engine
3.b.. Install Yum Utilities | Config Manager
$ sudo yum install -y yum-utils
3.c.. Setup the Docker Repository
$ sudo yum-config-manager --add-repo https://download.docker.com/linux/cen...
3.d.. Install Docker Engine, Docker CLI, Docker RUNTIME
$ sudo yum install -y docker-ce docker-ce-cli containerd.io
Step 4. Configure Docker Daemon for cgroups management & Start Docker
4.a.. Create directory
$ sudo mkdir /etc/docker
4.b.. Copy the below contents in this file.. /etc/docker/daemon.json
Content:
{
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2"
}
$ sudo systemctl daemon-reload
$ sudo systemctl restart docker
$ sudo systemctl enable docker
$ sudo systemctl status docker
Step 5. Install kubeadm, kubectl, kubelet
5.a.. Copy the below contents in this file.. /etc/yum.repos.d/kubernetes.repo
Content:
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum...\$basearch
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum... https://packages.cloud.google.com/yum...
exclude=kubelet kubeadm kubectl
5.b.. Set SELinux in permissive mode (effectively disabling it)
$ sudo setenforce 0
$ sudo sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config
$ sudo yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes
$ sudo systemctl enable --now kubelet
Step 6. Configuring a cgroup driver
Ignore if docker is used as a CRI
Step 7. Deploy a kubernetes cluster using kubeadm
Run only in Master node
$ kubeadm init --pod-network-cidr=10.10.0.0/16 --apiserver-advertise-address=master_nodeIP
To start using your cluster, you need to run the following as a regular user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
Alternatively, if you are the root user, you can run:
export KUBECONFIG=/etc/kubernetes/admin.conf
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
https://kubernetes.io/docs/concepts/c...
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.74.10:6443 --token l431j0.0tz0bbuu7hj64lw5 \
--discovery-token-ca-cert-hash sha256:1743115f18a7b8761105ff5465cd1aeed74a2e8a3f326405da61681d07fdb0e0
Step 8. Install CNI for POD Networking
Run only in Master node
Weave Networks:
$ kubectl apply -f "https://cloud.weave.works/k8s/net?k8s... version | base64 | tr -d '\n')"
Step 9. Join the worker nodes to the master
Run in Worker Nodes as "Root"
kubeadm join 192.168.74.10:6443 --token l431j0.0tz0bbuu7hj64lw5 \
--discovery-token-ca-cert-hash sha256:1743115f18a7b8761105ff5465cd1aeed74a2e8a3f326405da61681d07fdb0e0
Make sure to replace your tokens and IP's in the above command accordingly
Step 10. Access the K8s Cluster & Deploy a POD
kubectl run vsparkz --image nginx