[Tutorial] Installing Kubernetes Manually

[Tutorial] Installing Kubernetes Manually

1. Letting iptables see bridged traffic

###############
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

sudo modprobe overlay
sudo modprobe br_netfilter

# sysctl params required by setup, params persist across reboots
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-iptables  = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward                 = 1
EOF

############

sudo sysctl --system

2. Allow Required Firewall Ports

sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 80 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 443 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 9000 -j ACCEPT
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 9090 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 9100 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 9443 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 9796 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 8080 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 8001 -j ACCEPT
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 2376 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 2379:2380 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 6443 -j ACCEPT  
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 6783:6784 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 9099:9100 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 179 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 30000:32767 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 10250:10258 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 53 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p udp --dport 53 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 5000 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 5080 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 5432 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 111 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 8443 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 8472 -j ACCEPT 
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 45014 -j ACCEPT 
sudo netfilter-persistent save

or

sudo iptables -I INPUT -m state --state NEW -p tcp --dport 80 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 443 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 9090 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 9100 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 9443 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 9796 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 8080 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 8001 -j ACCEPT
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 2376 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 2379:2380 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 6443 -j ACCEPT  
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 6783:6784 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 9099:9100 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 179 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 30000:32767 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 10250:10258 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 53 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p udp --dport 53 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 5000 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 5080 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 5432 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 111 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 8443 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 8472 -j ACCEPT 
sudo iptables -I INPUT -m state --state NEW -p tcp --dport 45014 -j ACCEPT 
sudo netfilter-persistent save

3. Installing runtime or Docker Engine

Update the apt package index and install packages to allow apt to use a repository over HTTPS:

sudo apt-get update

sudo apt-get install \
    ca-certificates \
    curl \
    gnupg \
    lsb-release

Add Docker’s official GPG key:

 curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

Use the following command to set up the stable repository.

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 > /dev/null

Install Docker Engine

sudo apt-get update
sudo apt-get install docker-ce docker-ce-cli containerd.io docker-compose-plugin

4. Configure systemd driver

create or edit /etc/docker/daemon.json

{
  "exec-opts": ["native.cgroupdriver=systemd"]
}

restart docker service

sudo systemctl restart docker

5. Installing kubeadm, kubelet and kubectl

Update the apt package index and install packages needed to use the Kubernetes apt repository:

sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl

Download the Google Cloud public signing key:

sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg

Add the Kubernetes apt repository:

echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list

Update apt package index, install kubelet, kubeadm and kubectl, and pin their version:

sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubectl

CERTKEY=$(kubeadm certs certificate-key)
echo $CERTKEY

Run this ONLY on Control Plane

sudo kubeadm init --apiserver-cert-extra-sans=your.FQDN.COM,your.external.IP --pod-network-cidr=10.32.0.0/12 --control-plane-endpoint=your.FQDN.COM --upload-certs --certificate-key=$CERTKEY

or

kubeadm init

You can now join any number of the control-plane node running the following command on each as root:

kubeadm join your.FQDN.COM:6443 --token XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX \
--discovery-token-ca-cert-hash sha256:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX \
--control-plane --certificate-key XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

The above command will be generated after control plane has successfully initiallized.

To add Worker Nodes

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join your.FQDN.COM:6443 --token XXXXXXXXXXXXXXXXXXXXXXX \
--discovery-token-ca-cert-hash sha256:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Use below to reset any Master / Control Plane, or worker nodes

## remove cluster
sudo kubeadm reset
sudo rm -rf /etc/kubernetes
sudo rm -rf /etc/cni/net.d
sudo rm -rf /var/lib/kubelet
sudo rm -rf /var/lib/etcd
sudo rm -rf $HOME/.kube

Relevant FAQs:

What is Kubernetes is used for?

Kubernetes, often abbreviated as “K8s”, orchestrates containerized applications to run on a cluster of hosts. The K8s system automates the deployment and management of cloud native applications using on-premises infrastructure or public cloud platforms. [2]

What is Kubernetes and Docker?

In a nutshell, Docker is a suite of software development tools for creating, sharing and running individual containers; Kubernetes is a system for operating containerized applications at scale. Think of containers as standardized packaging for microservices with all the needed application code and dependencies inside. [3]

What's the difference between Docker and Kubernetes?

The difference between the two is that Docker is about packaging containerized applications on a single node and Kubernetes is meant to run them across a cluster. Since these packages accomplish different things, they are often used in tandem. Of course, Docker and Kubernetes can be used independently. [4]

Is Kubernetes free?

Pure open source Kubernetes is free and can be downloaded from its repository on GitHub. Administrators must build and deploy the Kubernetes release to a local system or cluster -- or to a system or cluster in a public cloud, such as AWS, Google Cloud or Microsoft Azure. [5]

Why is Kubernetes called K8s?

By the way, if you're wondering where the name “Kubernetes” came from, it is a Greek word, meaning helmsman or pilot. The abbreviation K8s is derived by replacing the eight letters of “ubernete” with the digit 8. [6]

References:

[1] https://faun.pub/free-ha-multi-architecture-kubernetes-cluster-from-oracle-c66b8ce7cc37

[2] https://www.vmware.com/topics/glossary/content/kubernetes.html

[3] https://www.dynatrace.com/news/blog/kubernetes-vs-docker/

[4] https://containerjournal.com/editorial-calendar/best-of-2021/whats-the-difference-between-docker-and-kubernetes/

[5] https://www.techtarget.com/searchitoperations/answer/Is-Kubernetes-free-as-an-open-source-software

[6] https://www.bmc.com/blogs/what-is-kubernetes/