Kubeadm create kubernetes cluster

kubeadm Create clusters

We use “ Public cloud - Qingyun ” The server provided as today's demo operation . Prepare three machines , One master node , Two work nodes .

Prerequisite

Kubernetes The installation of the cluster depends on the containerized running environment , So we must first install on each node docker. Methods refer to my previous article .

Docker install , Environment configuration description , Alibaba cloud image acceleration configuration

1、 Based on the environment

All machines perform the following operations .

1. Each machine sets its own domain name

hostnamectl set-hostname xxxx

2. Ban SELinux

sudo setenforce 0
sudo sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

3. close swap Partition

swapoff -a  
sed -ri 's/.*swap.*/#&/' /etc/fstab

4. allow iptables Check bridge flow

cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
br_netfilter
EOF

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

2、 install kubelet、kubeadm、kubectl

#  Configure the mirror warehouse address 
cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
   http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
exclude=kubelet kubeadm kubectl
EOF

#  Download the specified version 
sudo yum install -y kubelet-1.20.9 kubeadm-1.20.9 kubectl-1.20.9 --disableexcludes=kubernetes

#  immediately / Boot up 
sudo systemctl enable --now kubelet

This is done ,kubelet Now it will restart every few seconds , Because it fell into a wait kubeadm Dead loop of instructions

3. Use kubeadm Leading the cluster

Download the images required by each machine

#  Write a script , Specify the required version of each component 
sudo tee ./images.sh <<-'EOF'
#!/bin/bash
images=(
kube-apiserver:v1.20.9
kube-proxy:v1.20.9
kube-controller-manager:v1.20.9
kube-scheduler:v1.20.9
coredns:1.7.0
etcd:3.4.13-0
pause:3.2
)
for imageName in ${images[@]} ; do
docker pull registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/$imageName
done
EOF

#  Add executable permissions and execute scripts to download .
chmod +x ./images.sh && ./images.sh

Through this step, you can download the components needed to create the cluster . The work node only needs to download kube-proxy that will do , It doesn't matter if you download them all .

4. Initialize the master node

# Add... To all machines master Domain mapping 
echo "172.31.0.2  cluster-endpoint" >> /etc/hosts

The purpose of this step is to tell each node which node i will use as the master node （ Cluster entrance ）. Here you need to change it to your own ip, I use the intranet of the public cloud ip.

# Master initialization , Run this command only on the primary node 
kubeadm init \
--apiserver-advertise-address=172.31.0.2 \
--control-plane-endpoint=cluster-endpoint \
--image-repository registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images \
--kubernetes-version v1.20.9 \
--service-cidr=10.96.0.0/16 \
--pod-network-cidr=192.168.0.0/16

This actually defines what I will create in the future service and pod The network segment used when . We need to pay attention to apiserver-advertise-address For your own master node ip, And ensure that all network ranges do not overlap .pod-network-cidr If there is any modification, we need to modify the network range of the network components .

The following shows the cluster master Node initialization succeeded .

Your Kubernetes control-plane 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

Alternatively, if you are the root user, you can run:

  export KUBECONFIG=/etc/kubernetes/admin.conf

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 control-plane nodes by copying certificate authorities
and service account keys on each node and then running the following as root:

  kubeadm join cluster-endpoint:6443 --token xsmvuy.43k3verg00x4s5gs \
    --discovery-token-ca-cert-hash sha256:2d4a06dfe981eb1274831a027690fdfa3a6c89d0968af331d6d26c16f35e7bdb \
    --control-plane 

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join cluster-endpoint:6443 --token xsmvuy.43k3verg00x4s5gs \
    --discovery-token-ca-cert-hash sha256:2d4a06dfe981eb1274831a027690fdfa3a6c89d0968af331d6d26c16f35e7bdb

We can execute the corresponding commands according to the prompts .

5. Install network components

#  Run this command only on the primary node 
curl https://docs.projectcalico.org/manifests/calico.yaml -O

kubectl apply -f calico.yaml

6. Join in worker node

#  Run this command only on the work node 
kubeadm join cluster-endpoint:6443 --token xsmvuy.43k3verg00x4s5gs \
    --discovery-token-ca-cert-hash sha256:2d4a06dfe981eb1274831a027690fdfa3a6c89d0968af331d6d26c16f35e7bdb

These contents are still done according to the prompt information .

Add ： above token The effective time is 24 Hours , After expiration, use the following command to regenerate on the primary node .

kubeadm token create --print-join-command

High availability deployment , Also at this step , Use the command to add a master node .

7. Verification cluster

[[email protected] ~]# kubectl get nodes
NAME          STATUS   ROLES                  AGE   VERSION
k8s-master    Ready    control-plane,master   89m   v1.20.9
k8s-worker1   Ready    <none>                 68m   v1.20.9
k8s-worker2   Ready    <none>                 68m   v1.20.9
[[email protected] ~]#

thus , One kubernetes The cluster has been set up .

This paper is written by mdnice Multi platform Publishing