Kubernetes Installation / Using kubeadm / Ubuntu 16.04 Environment

1. Installation Environment

The installation environment is as follows.

• VirtualBox 5.0.14r
  • Master Node: Ubuntu Desktop 16.04.2 64bit * 1
  • Worker Node: Ubuntu Server 16.04.2 64bit * 2
• Kubernetes 1.7.1
  • Network Plugin: flannel
  • Dashboard Addon: Dashboard
• kubeadm
  • When building a cluster environment using VMs, Kubernetes can be easily installed using kubeadm.
• Docker 1.12.6
  • Kubernetes recommends version 1.12.x.
• Password
  • For easy installation, all passwords required for Kubernetes installation are unified to root.
• Installation proceeds as the root user on all nodes.

2. Node Configuration

Create virtual Master and Worker nodes (VMs) as shown in [Figure 1] using VirtualBox.

• Hostname: Master Node - ubuntu01, Worker Node1 - ubuntu02, Worker Node2 - ubuntu03
• NAT: Build a 10.0.0.0/24 network using the “NAT network” provided by VirtualBox.
• Router: Build a 192.168.77.0/24 network using a router. (NAT)

2.1. Master Node

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source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto enp0s3
iface enp0s3 inet static
address 10.0.0.11
netmask 255.255.255.0
gateway 10.0.0.1
dns-nameservers 8.8.8.8

auto enp0s8
iface enp0s8 inet static
address 192.168.77.170
netmask 255.255.255.0
gateway 192.168.77.1
dns-nameservers 8.8.8.8

Modify /etc/network/interfaces as shown in [File 1].

2.2. Worker Nodes

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source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto enp0s3
iface enp0s3 inet static
address 10.0.0.31
netmask 255.255.255.0
gateway 10.0.0.1
dns-nameservers 8.8.8.8

Modify Worker Node 01’s /etc/network/interfaces as shown in [File 2].

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source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto enp0s3
iface enp0s3 inet static
address 10.0.0.41
netmask 255.255.255.0
gateway 10.0.0.1
dns-nameservers 8.8.8.8

Modify Worker Node 02’s /etc/network/interfaces as shown in [File 3].

3. Package Installation

3.1. All Nodes

(All)$ sudo apt-get update
(All)$ sudo apt-get install apt-transport-https ca-certificates curl software-properties-common
(All)$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
(All)$ sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb-release -cs) stable"
(All)$ sudo apt-get update
(All)$ sudo apt-get install docker.io=1.12.6-0ubuntu1~16.04.1

Install Docker.

(All)$ apt-get update && apt-get install -y apt-transport-https curl
(All)$ curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
(All)$ echo deb http://apt.kubernetes.io/ kubernetes-xenial main > /etc/apt/sources.list.d/kubernetes.list
(All)$ apt-get update
(All)$ apt-get install -y kubelet kubeadm

Install kubelet and kubeadm.

3.2. Master Node

(Master)$ sudo snap install kubectl --classic

Install kubectl.

4. Cluster Setup

4.1. Master Node

(Master)$ kubeadm init --apiserver-advertise-address=10.0.0.11 --pod-network-cidr=10.244.0.0/16
...
kubeadm join --token 76f75a.6fbcc5e0e6e74c89 10.0.0.11:6443

Proceed with kubeadm initialization. After execution, you can obtain the key value. 10.0.0.11 is the Master IP of the NAT Network.

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

Configure kubectl config.

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if [ -f /etc/bash-completion ] && ! shopt -oq posix; then
    . /etc/bash-completion
fi

source <(kubectl completion bash)

Configure kubectl autocomplete. Add the content from [File 4] to ~/.bashrc.

(Master)$ kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel-rbac.yml
(Master)$ kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

Install the Network Addon (flannel).

(Master)$ kubectl create -f https://git.io/kube-dashboard

Install the Dashboard Addon (Dashboard).

4.2. Worker Nodes

(Worker)$ kubeadm join --token 76f75a.6fbcc5e0e6e74c89 10.0.0.11:6443

Configure the cluster. Execute the kubeadm join ~~ command that appears as a result of kubeadm init on all worker nodes.

4.3. Verification

(Master)$ kubectl get nodes
NAME       STATUS     AGE       VERSION
ubuntu01   Ready      41m       v1.7.1
ubuntu02   Ready      49s       v1.7.1
ubuntu03   Ready      55s       v1.7.1

Check the cluster from the Master Node.

(Master)$ kubectl proxy

After executing the kubectl proxy command, access http://localhost:8001/ui from the Master Node via a web browser.

5. References

• Kubernetes Installation: https://kubernetes.io/docs/setup/independent/install-kubeadm/
• Docker Installation: https://docs.docker.com/engine/installation/linux/docker-ce/ubuntu/
• flannel Issue: https://github.com/coreos/flannel/issues/671