Follow this documentation to set up a Kubernetes cluster on CentOS 7 Virtual machines.
This documentation guides you in setting up a cluster with one master node and two worker nodes.
Master: t2.medium Worker Nodes: t2.micro
6443
32750
10250
4443
443
8080
179 --> Should be allowed for Master and Worker nodes.
Perform all the commands as root user unless otherwise specified
Use the Docker repository to install docker.
If you use docker from CentOS OS repository, the docker version might be old to work with Kubernetes v1.13.0 and above
```sh
yum install -y -q yum-utils device-mapper-persistent-data lvm2 > /dev/null 2>&1
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo > /dev/null 2>&1
yum install -y -q docker-ce >/dev/null 2>&1
systemctl enable docker
systemctl start docker
setenforce 0
sed -i --follow-symlinks 's/^SELINUX=enforcing/SELINUX=disabled/' /etc/sysconfig/selinux
systemctl disable firewalld
systemctl stop firewalld
sed -i '/swap/d' /etc/fstab
swapoff -a
cat >>/etc/sysctl.d/kubernetes.conf<<EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system
cat >>/etc/yum.repos.d/kubernetes.repo<<EOF
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
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
EOF
yum install -y kubeadm-1.15.6-0.x86_64 kubelet-1.15.6-0.x86_64 kubectl-1.15.6-0.x86_64
systemctl enable kubelet
systemctl start kubelet
kubeadm init --apiserver-advertise-address=<MasterServerIP> --pod-network-cidr=192.168.0.0/16
To be able to use kubectl command to connect and interact with the cluster, the user needs kube config file.
In my case, the user account is praveen
mkdir /home/praveen/.kube
cp /etc/kubernetes/admin.conf /home/praveen/.kube/config
chown -R praveen:praveen /home/praveen/.kube
This has to be done as the user in the above step (in my case it is praveen)
kubectl create -f https://docs.projectcalico.org/v3.9/manifests/calico.yaml
kubeadm token create --print-join-command
Use the output from kubeadm token create command in previous step from the master server and run here.
kubectl get nodes
kubectl get cs