最近自己琢磨了下K8S集群环境的搭建，环境搭建很简单，这边整理了v1.20.1版本的搭建步骤
一、安装前准备
1、有条件的话直接上腾讯、阿里公有云买3台云主机，最小配置2C2G20G就好
2、没条件的话，就在自己电脑上用Vmware开3台虚拟机，配置一样2C2G20G
3、操作系统CentOS 7.x，本文使用的是7.6版本做演示
二、环境初始化
分别在3台机器上面执行
#根据规划设置主机名
hostnamectl set-hostname master
hostnamectl set-hostname node1
hostnamectl set-hostname node2
#添加hosts
cat >> /etc/hosts << EOF
192.168.153.129 master
192.168.153.130 node1
192.168.153.131 node2
EOF
#关闭防火墙
systemctl stop firewalld && systemctl disable firewalld
#关闭selinux
sed -i 's/enforcing/disabled/' /etc/selinux/config && setenforce 0
#关闭swap
swapoff -a && sed -ri 's/.*swap.*/#&/' /etc/fstab
#时间同步
yum install ntpdate -y && ntpdate ntp2.aliyun.com
#配置内核参数，将桥接的IPv4流量传递到iptables的链
cat > /etc/sysctl.d/k8s.conf <<EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system
三、安装Docker
分别在3台机器上面执行
# 1: 安装必要的一些系统工具
sudo yum install -y yum-utils device-mapper-persistent-data lvm2
# 2: 添加软件源信息
sudo yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
# 3: 更新并安装Docker-CE
sudo yum makecache fast
sudo yum -y install docker-ce
# 4: 开启Docker服务
sudo systemctl start docker && systemctl enable docker
# 可以通过修改daemon配置文件/etc/docker/daemon.json来使用加速器
sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
"registry-mirrors": ["https://s2q9fn53.mirror.aliyuncs.com"]
}
EOF
sudo systemctl daemon-reload && sudo systemctl restart docker
四、安装kubelet、kubeadm、kubectl
分别在3台机器上面执行
#添加kubernetes阿里YUM源
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
# 可以用下面的命令查看可以安装的版本
yum list kubeadm --showduplicates | sort -r
#安装
yum install -y kubelet-1.20.1-0 kubeadm-1.20.1-0 kubectl-1.20.1-0 --disableexcludes=kubernetes
# 启动开机启动kubelet
systemctl start kubelet
systemctl enable kubelet
五、部署Kubernetes Master
只在master上面执行
# 创建集群
kubeadm init --kubernetes-version=v1.20.1 --apiserver-advertise-address=192.168.153.129 --image-repository registry.aliyuncs.com/google_containers --service-cidr=10.10.0.0/16 --pod-network-cidr=10.122.0.0/16
参数说明：
kubernetes-version：要安装的版本
pod-network-cidr：负载容器的子网网段
service-cidr：svc网段
image-repository：指定镜像仓库
apiserver-advertise-address：节点绑定的服务器ip(写master节点IP)
#提示initialized successfully！表示初始化成功
# 接着根据提示拷贝admin.config的内容到当前用户的$HOME/.kube/config中并授权
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
#执行完后可以运行查看node节点情况，这时候可以看到master节点是noready状态，原因是没有部署网络插件
kubectl get nodes
六、部署网络插件
常用的网络插件有flannel和calico，这里选择flannel
# 创建目录
mkdir -p /opt/yaml
# 编辑kube-flannel.yaml
获取部署flannel的yaml文件（https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml）到/opt/yaml目录中，（链接需要翻墙才能访问，这边贴下获取到的内容）
vim /opt/yaml/kube-flannel.yaml
---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
name: psp.flannel.unprivileged
annotations:
seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
privileged: false
volumes:
- configMap
- secret
- emptyDir
- hostPath
allowedHostPaths:
- pathPrefix: "/etc/cni/net.d"
- pathPrefix: "/etc/kube-flannel"
- pathPrefix: "/run/flannel"
readOnlyRootFilesystem: false
# Users and groups
runAsUser:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
fsGroup:
rule: RunAsAny
# Privilege Escalation
allowPrivilegeEscalation: false
defaultAllowPrivilegeEscalation: false
# Capabilities
allowedCapabilities: ['NET_ADMIN', 'NET_RAW']
defaultAddCapabilities: []
requiredDropCapabilities: []
# Host namespaces
hostPID: false
hostIPC: false
hostNetwork: true
hostPorts:
- min: 0
max: 65535
# SELinux
seLinux:
# SELinux is unused in CaaSP
rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: flannel
rules:
- apiGroups: ['extensions']
resources: ['podsecuritypolicies']
verbs: ['use']
resourceNames: ['psp.flannel.unprivileged']
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- apiGroups:
- ""
resources:
- nodes
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes/status
verbs:
- patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: flannel
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: flannel
subjects:
- kind: ServiceAccount
name: flannel
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: flannel
namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
name: kube-flannel-cfg
namespace: kube-system
labels:
tier: node
app: flannel
data:
cni-conf.json: |
{
"name": "cbr0",
"cniVersion": "0.3.1",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
},
{
"type": "portmap",
"capabilities": {
"portMappings": true
}
}
]
}
net-conf.json: |
{
"Network": "10.244.0.0/16",
"Backend": {
"Type": "vxlan"
}
}
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/os
operator: In
values:
- linux
hostNetwork: true
priorityClassName: system-node-critical
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.14.0
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.14.0
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: ["NET_ADMIN", "NET_RAW"]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
# 将quay.io换成quay.mirrors.ustc.edu.cn（中科大）的镜像
sed -i 's#quay.io/coreos/flannel#quay.mirrors.ustc.edu.cn/coreos/flannel#' /opt/yaml/kube-flannel.yaml
# 部署flannel
kubectl apply -f /opt/yaml/kube-flannel.yaml
#等个几分钟，再看master上节点状态就是ready了
七、扩容node节点进集群
在两台node上面执行添加命令
#命令在第五步，创建集群成功后会显示在界面上
kubeadm join 192.168.153.129:6443 --token 7spol7.nxxabat5ljyws8xo --discovery-token-ca-cert-hash sha256:4f31b94b2beda59334b5da507673752605ab49fde6ef87487c81b314a39b466f
#如果忘记token，可以在master节点重新生成，token有效期24小时
kubeadm token create --print-join-command
#在master节点上运行查看node节点命令，就可以看到3台node节点了
八、检查集群状态
# 查看node状态都是ready
kubectl get nodes
# 看出pod状态都是running
kubectl get pod --all-namespaces
#查看集群状态都是Healthy ok
kubectl get cs
如果出现unhealthy，分别修改下面两个文件，注释 - --port=0，然后重启kubelet
vim /etc/kubernetes/manifests/kube-controller-manager.yaml
vim /etc/kubernetes/manifests/kube-scheduler.yaml
systemctl restart kubelet.service