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kubernetes-install.md

Install Kubernetes

Install and configure prerequisites

sudo apt update
sudo apt upgrade -y
sudo apt install -y ca-certificates curl gnupg lsb-release
cat <<EOF | sudo tee /etc/modules-load.d/containerd.conf
overlay
br_netfilter
EOF

sudo modprobe overlay
sudo modprobe br_netfilter

cat <<EOF | sudo tee /etc/sysctl.d/99-kubernetes-cri.conf
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF

sudo sysctl --system

Install Containerd

Using Docker repository (not recomended)

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list
sudo apt update
sudo apt install -y containerd.io runc
cat <<EOF | sudo tee -a /etc/containerd/config.toml
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
SystemdCgroup = true
EOF
sudo sed -i 's/^disabled_plugins \=/\#disabled_plugins \=/g' /etc/containerd/config.toml
sudo systemctl restart containerd
sudo systemctl status containerd

Using Containerd binaries (offical)

Install Containerd core

First, download the latest version of containerd from GitHub and extract the files to the /usr/local/ directory.

# Set Containerd version
export "containerd_version=1.6.8"

# Download Containerd
wget "https://github.com/containerd/containerd/releases/download/v${containerd_version}/containerd-${containerd_version}-linux-amd64.tar.gz"
# Extract Containerd
sudo tar Czxvf /usr/local "containerd-${containerd_version}-linux-amd64.tar.gz"

Download Containerd service

wget https://raw.githubusercontent.com/containerd/containerd/main/containerd.service

Configuration

sudo mkdir -p /etc/containerd/
containerd config default | sudo tee /etc/containerd/config.toml
sudo sed -i 's/SystemdCgroup \= false/SystemdCgroup \= true/g' /etc/containerd/config.toml

Install Containerd service

sudo mv containerd.service /usr/lib/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now containerd

View Containerd service status

sudo systemctl status containerd

Install runC

runC is an open-source container runtime for spawning and running containers on Linux according to the OCI specification.

Download the latest version of runC from GitHub and install it as /usr/local/sbin/runc.

export "runc_version=1.1.4"

wget "https://github.com/opencontainers/runc/releases/download/v${runc_version}/runc.amd64"

sudo install -m 755 runc.amd64 /usr/local/sbin/runc

Install CNI Plugins For Containerd

For the container to run, you need to install CNI plugins. So, download the latest version of CNI plugins from GitHub and place them in the /opt/cni/bin directory.

export "cni_version=1.1.1"

sudo mkdir -p /opt/cni/bin/

sudo wget "https://github.com/containernetworking/plugins/releases/download/v${cni_version}/cni-plugins-linux-amd64-v${cni_version}.tgz"

sudo tar Cxzvf /opt/cni/bin cni-plugins-linux-amd64-v${cni_version}.tgz

Restart the containerd service.

sudo systemctl restart containerd

Install Nerdctl (Optional)

nerdctl is a Docker-compliant command-line interface for containerd. It is not part of the core package. So, this has to be installed separately.

Download the latest version of nerdctl from GitHub and extract it to the /usr/local/bin directory.

export "nerdctl_version=0.22.2"
wget "https://github.com/containerd/nerdctl/releases/download/v${nerdctl_version}/nerdctl-${nerdctl_version}-linux-amd64.tar.gz"

sudo tar Cxzvf /usr/local/bin nerdctl-${nerdctl_version}-linux-amd64.tar.gz

Install Kubernetes

Now that containerd is installed on both our nodes, we can start our Kubernetes installation.

Add Kubernetes key on both nodes

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add

Add Kube repository on both nodes

cat <<EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list
deb https://apt.kubernetes.io/ kubernetes-xenial main
EOF

Update both your systems and install all the Kubernetes modules

sudo apt-get update

sudo apt-get install -y kubelet kubeadm kubectl

Set hostnames

On the master node, run:

sudo hostnamectl set-hostname "master-node"
exec bash

On the worker node, run:

sudo hostnamectl set-hostname "w-node1"
exec bash

Set the hostnames in the /etc/hosts file of the worker:

sudo cat <> /etc/hosts
160.119.248.60 master-node
160.119.248.162 node1 W-node1
EOF

Config firewall rules

Set up the following firewall rules on the master node

sudo ufw allow 6443/tcp
sudo ufw allow 2379/tcp
sudo ufw allow 2380/tcp
sudo ufw allow 10250/tcp
sudo ufw allow 10251/tcp
sudo ufw allow 10252/tcp
sudo ufw allow 10255/tcp
sudo ufw reload

Set up the following firewall rules on the worker node

sudo ufw allow 10251/tcp
sudo ufw allow 10255/tcp
sudo ufw reload

Turn swap off

It’s required for kubelet to work, run on both nodes

sudo swapoff –a

Enable kubelet service on both nodes:

sudo systemctl enable kubelet

Deploy the Kubernetes cluster

Initialise cluster

On the master node, execute the following command to initialise the Kubernetes cluster:

sudo kubeadm init

The process can take a few minutes. The last few lines of your output should look similar to this:

Your Kubernetes control-plane has initialized successfully!
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/cluster-administration/addons/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.2.105:6443 --token abcdef.abcdefghijklmnop \
--discovery-token-ca-cert-hash sha256:8dfad80a388f4c93a9d5fb6d0b5b3ceda08305bac044ec8417e9f4f3c473893d

Copy the kubeadm join from the end of the above output. We will be using this command to add worker nodes to our cluster.

If you forgot to copy or misplaced the command, don’t worry; you can get it back by executing this command:

sudo kubeadm token create --print-join-command

Create and claim directory

As indicated by the output above, we need to create a directory and claim its ownership to start managing our cluster.

Run the following commands:

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

Deploy pod network to cluster

We will use Flannel to deploy a pod network to our cluster:

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

You should see the following output after running the above command:

podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created

You should be able to verify that your master node is ready now:

sudo kubectl get nodes

Output:

NAME          STATUS   ROLES                  AGE   VERSION
master-node   Ready    control-plane,master   90s   v1.23.3

…and that all the pods are up and running:

sudo kubectl get pods --all-namespaces
Output
NAMESPACE     NAME                                  READY   STATUS              RESTARTS        AGE
kube-system   coredns-957326482-zdgsd               0/1     Running		0               22m
kube-system   coredns-957326482-srfgh               0/1     Running		0               22m
kube-system   etcd-master-node                      1/1     Running             0               22m
kube-system   kube-apiserver-master-node            1/1     Running             0               22m
kube-system   kube-controller-manager-master-node   1/1     Running             0               22m
kube-system   kube-flannel-ds-dnjsd                 0/1     Running		0		22m
kube-system   kube-flannel-ds-dfjyf                 0/1     Running    		0     		22m
kube-system   kube-proxy-jfbur                      1/1     Running             0               22m
kube-system   kube-proxy-sdfeh                      1/1     Running             0               20m
kube-system   kube-scheduler-master-node            1/1     Running             0               22m

Add nodes

At this point, we are ready to add nodes to our cluster.

Copy your own kubeadm join command from Step: Initialise cluster and run it on the worker node:

kubeadm join 192.168.2.105:6443 --token abcdef.abcdefghijklmnop \
--discovery-token-ca-cert-hash sha256:8dfad80a388f4c93a9d5fb6d0b5b3ceda08305bac044ec8417e9f4f3c473893d

Output:

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run kubectl get nodes on the control-plane to see this node join the cluster.

To verify that the worker node indeed got added to the cluster, execute the following command on the master node:

kubectl get nodes

Output:

NAME          STATUS   ROLES                  AGE     VERSION
master-node   Ready    control-plane,master   2m54s   v1.25.0
w-node1       Ready                           27s     v1.25.0

You can set the role for your worker node using:

sudo kubectl label node w-node1 node-role.kubernetes.io/worker=worker

Get nodes again to verify:

kubectl get nodes

Output:

NAME          STATUS   ROLES                  AGE     VERSION
master-node   Ready    control-plane,master   4m34s   v1.25.0
w-node1       Ready    worker                 1m24s   v1.25.0

To add more nodes, repeat this Add nodes step on more machines.

That’s it! Your two-node Kubernetes cluster is up and running!

Kubernetes dashboard deploy

https://gist.github.com/AliKhadivi/d7067f886985dc5f4820387edeffb7bd

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