2018-08-31
kubemaster: 192.168.1.99
kube2: 192.168.1.109
kube3: 192.168.1.167
setenforce 0
sed -i --follow-symlinks 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/sysconfig/selinux
Next, disable swap (on all three machines) with the following command:
swapoff -a
/etc/fstab and comment out the swap entry like this:
# /dev/mapper/centos-swap swap swap defaults 0 0
enabling the br_netfilter kernel module on all three servers.
This is done with the following commands:
modprobe br_netfilter
echo '1' > /proc/sys/net/bridge/bridge-nf-call-iptables
It’s time to install the necessary Docker tool. On all three machines,
install the Docker-ce dependencies with the following command:
yum install -y yum-utils device-mapper-persistent-data lvm2
Next, add the Docker-ce repository with the command:
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
Install Docker-ce with the command:
yum install -y docker-ce
vi /etc/yum.repos.d/kubernetes.repo
[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
Save and close that file. Install Kubernetes with the command:
yum install -y kubelet kubeadm kubectl
Cgroup changes
Now we need to ensure that both Docker-ce and Kubernetes belong to the same control group (cgroup). By default,
Docker should already belong to cgroupfs
| (you can check this with the command docker info | grep -i cgroup). |
To add Kubernetes to this, issue the command:
sed -i 's/cgroup-driver=systemd/cgroup-driver=cgroupfs/g' /etc/systemd/system/kubelet.service.d/10-kubeadm.conf
Restart the systemd daemon and the kubelet service with the commands:
systemctl daemon-reload
systemctl restart kubelet
Initialize the Kubernetes cluster
adjusting the IP addresses to fit your needs):
kubeadm init --apiserver-advertise-address=192.168.1.99 --pod-network-cidr=192.168.1.0/16
Once that completes, head over to kube2 and issue the command (adjusting the IP address to fit your needs):
kubeadm join 192.168.1.99:6443 --token TOKEN --discovery-token-ca-cert-hash DISCOVERY_TOKEN
Where TOKEN and DISCOVERY_TOKEN are the tokens displayed after the initialization command completes.
Before Kubernetes can be used, we must take care of a bit of configuration.
Issue the following three commands (to create a new .kube configuration directory,
copy the necessary configuration file, and give the file the proper ownership):
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
Now we must deploy the flannel network to the cluster with the command:
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml