主机规划
使用 kubeadm 初始化 kubernetes 集群，操作系统为 CentOS 7.6.1810 x86_64，用到的各相关程序版本如下：
- ubuntu: v18.04.6 LTS
- kubeadm: v1.22.6
- docker: v20.10.6
- flannel: v1.0.1
| 主机名 | IP 地址 | 配置 |
|---|---|---|
| kubeadm-master-01 | 192.168.124.200 | 8GB Ram, 2vcpus |
| kubeadm-node-01 | 192.168.124.211 | 8GB Ram, 2vcpus |
| kubeadm-node-02 | 192.168.124.212 | 8GB Ram, 2vcpus |
| kubeadm-node-03 | 192.168.124.212 | 8GB Ram, 2vcpus |
准备
- 升级软件包
apt update
apt -y upgrade
- 主机名解析
cat >> /etc/hosts <<EOF
192.168.124.200 kubeadm-master-01
192.168.124.211 kubeadm-node-01
192.168.124.212 kubeadm-node-02
192.168.124.213 kubeadm-node-03
# 用来扩展集群为高可用集群
192.168.124.200 kubeadm-vip.linux.io
EOF
- 时间同步
cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
apt install ntpdate -y
ntpdate time1.aliyun.com
echo "*/3 * * * * /usr/sbin/ntpdate time1.aliyun.com &> /dev/null" >> /var/spool/cron/crontabs/root
- 关闭防火墙和 swap 分区
ufw disable
sed -i 's@^/swap@# &1@g' /etc/fstab && swapoff -a
- 调整内核参数
modprobe overlay && modprobe br_netfilter
cat >> /etc/sysctl.d/99-kubernetes-cri.conf << EOF
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
user.max_user_namespaces=28633
vm.swappiness=0
EOF
sysctl --system
- 配置 ipvs 功能
apt install ipvsadm ipset -y
modprobe ip_vs && modprobe ip_vs_rr && modprobe ip_vs_wrr && modprobe ip_vs_sh
cat <<EOF >> /etc/modules
ip_vs_rr
ip_vs_wrr
ip_vs_sh
ip_vs
EOF
reboot
lsmod | grep -e ip_vs -e nf_conntrack_ipv4
ip_vs_sh 16384 0
ip_vs_wrr 16384 0
ip_vs_rr 16384 0
ip_vs 151552 6 ip_vs_rr,ip_vs_sh,ip_vs_wrr
nf_defrag_ipv6 20480 1 ip_vs
nf_conntrack 135168 1 ip_vs
libcrc32c 16384 4 nf_conntrack,xfs,raid456,ip_vs
安装容器运行时
apt-get remove docker docker-engine docker.io
apt-get install apt-transport-https ca-certificates curl gnupg2 software-properties-common
curl -fsSL https://repo.huaweicloud.com/docker-ce/linux/ubuntu/gpg | sudo apt-key add -
add-apt-repository "deb [arch=amd64] https://repo.huaweicloud.com/docker-ce/linux/ubuntu $(lsb_release -cs) stable"
apt update
apt-cache madison docker-ce
apt install docker-ce=5:20.10.6~3-0~ubuntu-bionic -y
mkdir /etc/docker
cat >> /etc/docker/daemon.json << EOF
{
"registry-mirrors": ["https://o4uba187.mirror.aliyuncs.com"],
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2",
"graph": "/var/lib/docker"
}
EOF
systemctl enable docker --now
安装 Kubeadm
apt-get update && apt-get install -y apt-transport-https
curl https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add -
cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main
EOF
apt-get update
apt-get install kubeadm=1.22.5-00 kubelet=1.22.5-00 kubectl=1.22.5-00
systemctl enable kubelet.service
初始化 Master 节点
kubeadm init --kubernetes-version=v1.22.5 \
--control-plane-endpoint=kubeadm-vip.linux.io \
--apiserver-advertise-address=0.0.0.0 \
--pod-network-cidr=10.244.0.0/16 \
--service-cidr=10.96.0.0/12 \
--image-repository=registry.cn-hangzhou.aliyuncs.com/google_containers \
--ignore-preflight-errors=Swap | tee kubeadm-init.log
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 kubeadm-vip.linux.io:6443 --token pa5fyb.mcoy474qbznp8cvd \
--discovery-token-ca-cert-hash sha256:5c1deff287d32725b8c3eaab49a32afc4f046ff1514056b15f11535c1fb45df5 \
--control-plane
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join kubeadm-vip.linux.io:6443 --token pa5fyb.mcoy474qbznp8cvd \
--discovery-token-ca-cert-hash sha256:5c1deff287d32725b8c3eaab49a32afc4f046ff1514056b15f11535c1fb45df5
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
部署 Flannel
kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml
Join worker 节点
kubeadm join kubeadm-vip.linux.io:6443 --token pa5fyb.mcoy474qbznp8cvd \
--discovery-token-ca-cert-hash sha256:5c1deff287d32725b8c3eaab49a32afc4f046ff1514056b15f11535c1fb45df5
启用 IPVS 模式
kubectl edit cm kube-proxy -n kube-system
mode: "ipvs"
kubectl delete pod -n kube-system -l k8s-app=kube-proxy
ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 10.96.0.1:443 rr
-> 192.168.124.200:6443 Masq 1 0 0
TCP 10.96.0.10:53 rr
-> 10.244.0.2:53 Masq 1 0 0
-> 10.244.0.3:53 Masq 1 0 0
TCP 10.96.0.10:9153 rr
-> 10.244.0.2:9153 Masq 1 0 0
-> 10.244.0.3:9153 Masq 1 0 0
UDP 10.96.0.10:53 rr
-> 10.244.0.2:53 Masq 1 0 0
-> 10.244.0.3:53 Masq 1 0 0
验证集群
kubectl create deployment myapp --image=ikubernetes/myapp:v1 --replicas=3
kubectl expose deployment myapp --port=80 --target-port=80
kubectl get pod -o wide && kubectl get svc
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
myapp-7d4b7b84b-98cx7 1/1 Running 0 83s 10.244.3.3 kubeadm-node-03 <none> <none>
myapp-7d4b7b84b-pfkqq 1/1 Running 0 83s 10.244.2.3 kubeadm-node-02 <none> <none>
myapp-7d4b7b84b-zg5dc 1/1 Running 0 83s 10.244.1.4 kubeadm-node-01 <none> <none>
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 60m
myapp ClusterIP 10.101.62.58 <none> 80/TCP 2m40s
kubectl exec -it myapp-7d4b7b84b-98cx7 -- wget -O - 10.244.1.4
Connecting to 10.244.1.4 (10.244.1.4:80)
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>
kubectl exec -it myapp-7d4b7b84b-98cx7 -- ping 192.168.124.212
kubectl exec -it myapp-7d4b7b84b-98cx7 -- nslookup myapp
nslookup: can't resolve '(null)': Name does not resolve
Name: myapp
Address 1: 10.101.62.58 myapp.default.svc.cluster.local
