Kubernetes Installation

 This article provides step by step approach how to install and configure 3 node Kubernetes cluster on Amazon EC2 RPM based instances.

Before Get Started

OS Requirements

Master and Worker nodes must be running with any one of the below Operating Systems:

• Ubuntu 16.04+
• Debian 9+
• CentOS 7
• Red Hat Enterprise Linux (RHEL) 7
• Fedora 25+
• Amazon Linux 2

Hardware Requirements

• RAM: 2 GB or More
• CPU: 2 CPU or More

OS Configuration

• Disable Swap

  • # swapoff -a 

• Disable SELinux

  • [root@ ~]$setenforce 0
    setenforce: SELinux is disabled
    [root@ ~]$
    # sudo sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

• Disable Firewal

  • # service iptables stop

  • If IP TABLES are enabled then configure IP tables to see bridged traffic

  • # modprobe br_netfilter
    # cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
    net.bridge.bridge-nf-call-ip6tables = 1
    net.bridge.bridge-nf-call-iptables = 1
    EOF
    # sudo sysctl --system

• Unique hostname, MAC address, and product_uuid 

  • [root@ ~]$ifconfig | grep ether
    ether 06:b5:b0:04:34:45 txqueuelen 1000 (Ethernet)
    [root@ ~]$

  • [root@ ~]$cat /sys/class/dmi/id/product_uuid
    EC2D3281-B316-79C1-CB8E-79BC63D66FDC
    [root@ ~]$

• Network connectivity between all cluster nodes including master.

Network Configuration

Ensure below ports are open on Master and Worker nodes.

Control-Plane Node (Master Node)

Worker Node

Install Packages

Required below packages installed in all nodes( master and worker nodes).

Master:

• docker: Container Runtime 
• kubeadm:  Command to bootstrap the cluster.
• kubectl: Command utility to  interact with K8s cluster API server.

Worker Node:

• docker: Container Runtime 
• kubelet: Service running on all nodes to managing starting pods and containers.

Configure Kubernetes Repo:

1.  Run below command to add Kubernetes Repo to the yum repo.

# cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-\$basearch
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
exclude=kubelet kubeadm kubectl
EOF

2. Run below command to  install  Packages

# yum install docker kubeadm kubectl kubelet --disableexcludes=kubernetes

Enable Services to start after reboot

[root@ ~]$chkconfig docker on
Note: Forwarding request to 'systemctl enable docker.service'.
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.

[root@ ~]$chkconfig kubelet on
Note: Forwarding request to 'systemctl enable kubelet.service'.
Created symlink from /etc/systemd/system/multi-user.target.wants/kubelet.service to /usr/lib/systemd/system/kubelet.service.
[root@ ~]$

Start Docker RunTime

[root@ ~]$ service docker start