Setup K8S Cluster

Build Base VM

VirtualBox VM Settings

Create a VM with two network interfaces:

Host Only Network
NAT

Base Memory:

2048 MB

HD Size

10 GB

Audio

Disabled

Install Ubuntu or Centos and enable/install openssh if available.

Enable both network interfaces

If you are installing Ubuntu server it will enable a primary network interface.

For VirtualBox VMs we are using 2 network interfaces:

a host only network for accessing the host from our machine without having to setup port forwarding. (primary)
a NAT network used for accessing the internet

>ifconfig -a

Add the missing interface to your interfaces config file and reboot

> vi /etc/network/interfaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).


source /etc/network/interfaces.d/*


# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto enp0s3
iface enp0s3 inet dhcp

auto enp0s8
iface enp0s8 inet dhcp

> reboot

Login and get IP address:

> ifconfig

enp0s3    Link encap:Ethernet  HWaddr 08:00:27:56:82:00  
          inet addr:192.168.56.3  Bcast:192.168.56.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe56:8200/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:170 errors:0 dropped:0 overruns:0 frame:0
          TX packets:112 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:18488 (18.4 KB)  TX bytes:19156 (19.1 KB)

enp0s8    Link encap:Ethernet  HWaddr 08:00:27:f0:a2:f5  
          inet addr:10.0.3.15  Bcast:10.0.3.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fef0:a2f5/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:329 errors:0 dropped:0 overruns:0 frame:0
          TX packets:141 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:389613 (389.6 KB)  TX bytes:10690 (10.6 KB)


...

Update apt-get

> sudo su

> apt-get update

Install openssh (if not already installed)

> apt-get install openssh-server

Now you can ssh into the virtual machine on the host-only network from your host

> ssh test@192.168.56.3

Install Docker

> sudo su

> apt-get install -y docker.io

Install Curl

> apt-get install -y apt-transport-https curl

Install Kubernetes

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee -a /etc/apt/sources.list.d/kubernetes.list
sudo apt-get update
sudo apt-get install -y kubectl kubelet kubeadm
sudo apt-mark hold kubelet kubeadm kubectl

Pull images

> kubeadm config images pull

[config/images] Pulled k8s.gcr.io/kube-apiserver:v1.13.1
[config/images] Pulled k8s.gcr.io/kube-controller-manager:v1.13.1
[config/images] Pulled k8s.gcr.io/kube-scheduler:v1.13.1
[config/images] Pulled k8s.gcr.io/kube-proxy:v1.13.1
[config/images] Pulled k8s.gcr.io/pause:3.1
[config/images] Pulled k8s.gcr.io/etcd:3.2.24
[config/images] Pulled k8s.gcr.io/coredns:1.2.6

Now clone (full clone) this VM with names:

k8master
k8worker1
k8worker2

For the k8master, set the CPU cores to 2.

Setup Networking on VMs

On the VMs that we have defined, lets get them configured.

VM	Ip Address
k8master	192.168.56.100
k8worker1	192.168.56.101
k8worker2	192.168.56.102

Set Hostname

> sudo vi /etc/hostname

k8master

> vi /etc/hosts

127.0.0.1       localhost
127.0.1.1       k8master

# The following lines are desirable for IPv6 capable hosts
::1     localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Set IP address

Set a static ip address for our host-only interface (enp0s3)

> sudo su

> vi /etc/network/interfaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
 
 
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 192.168.56.100
        netmask 255.255.255.0
        network 192.168.56.0
        broadcast 192.168.56.255


auto enp0s8
iface enp0s8 inet dhcp

Disable SWAP

> swapoff -va

> vi /etc/fstab

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type> <options>       <dump> <pass>
# / was on /dev/sda1 during installation
UUID=e7b204f7-9f41-42d4-b55f-292990f4137a /               ext4    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
#UUID=9ca9f4cb-876e-4e23-91a4-2f543b5537ac none            swap    sw              0       0

> reboot

Repeat for all VMs

Initialize Master

> sudo kubeadm init --apiserver-advertise-address 192.168.56.100 --pod-network-cidr 192.168.0.0/16

...
Your Kubernetes master 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

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/

You can now join any number of machines by running the following on each node
as root:

kubeadm join 192.168.56.100:6443 --token 69sqqp.yelc6ct7o3v3uoqp --discovery-token-ca-cert-hash sha256:03b55f52661338d761e8dd68203b738f3e126428cda239db81c2723a7bccba83

Record the kubeadm join command!

Install Network Plugin

> sudo kubectl apply -f https://docs.projectcalico.org/v2.6/getting-started/kubernetes/installation/hosted/kubeadm/1.6/calico.yaml

As your non root user:

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

Join Worker Nodes

User kubeadm join to join the cluster.

> kubeadm join 192.168.56.100:6443 --token gi6ugh.jufhrmb9rrcxn95c --discovery-token-ca-cert-hash sha256:6c9406ae054946f8f33122a8acf1afb9ae560d8aeffff3969c1f2218e4ddf9bb

Verify Everything is Working

> kubectl get pods --all-namespaces

NAMESPACE     NAME                                       READY   STATUS              RESTARTS   AGE
kube-system   calico-kube-controllers-74bbfbfd85-bnpwp   0/1     Pending             0          6d18h
kube-system   coredns-86c58d9df4-2qhsk                   0/1     ContainerCreating   0          6d19h
kube-system   coredns-86c58d9df4-dff98                   0/1     ContainerCreating   0          6d19h
kube-system   etcd-k8master                              1/1     Running             1          6d19h
kube-system   kube-apiserver-k8master                    1/1     Running             1          6d19h
kube-system   kube-controller-manager-k8master           1/1     Running             1          6d19h
kube-system   kube-proxy-dgmfh                           1/1     Running             1          6d19h
kube-system   kube-proxy-t9qsg                           1/1     Running             2          6d19h
kube-system   kube-proxy-zhrc4                           1/1     Running             0          6d18h
kube-system   kube-scheduler-k8master                    1/1     Running             1          6d19h

References

Reference	URL
Building a Kuburnetes Cluster	https://medium.com/@KevinHoffman/building-a-kubernetes-cluster-in-virtualbox-with-ubuntu-22cd338846dd

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