Kubeadm方式搭建K8S叢集
一、搭建k8s叢集（kubeadm方式）
kubeadm部署方式介紹
kubeadm是官方社群推出的一個用於快速部署kubernetes叢集的工具，這個工具能透過兩條指令完成一個kubernetes叢集的部署：
第一，建立一個master幾點 kubeadm init
第二，將node節點加入到當前叢集中 $kubeadm join <Master 節點的IP和埠>
安裝要求
部署kubernetes叢集機器需要滿足以下幾個條件：
1. 一臺或多臺機器，作業系統CentOs7.x-86_x64
2. 硬體配置：2GB或更多RAM，2個CPU或更多CPU，硬碟30GB或更多
3. 叢集中所有機器之間網路互通
4. 可以訪問外網，需要拉取映象
5. 禁止swap分割槽
最終目標
1. 在所有節點上安裝docker 和kubeadm
2. 部署kubernetes master
3. 部署容器網路外掛
4. 部署kubernetes node，將節點加入kubernetes叢集中
5. 部署Dashboard Web頁面，視覺化檢視Kubernetes資源
二、安裝步驟
- 安裝三臺虛擬機器，安裝作業系統centos7.x
192.168.72.129
192.168.72.130
192.168.72.131(master)
- 對三個作業系統進行初始化操作
# 關閉防火牆
systemctl stop fierwalld #臨時關閉
systemctl disable fierwalld #永久關閉
# 關閉selinux
sed -i 's/enforcing/disabled/' /etc/selinux/config # 永久
setenforce 0 # 臨時
# 關閉swap分割槽
swapoff -a #臨時
sed -ri 's/.*swap.*/#&/' /etc/fstab #永久
# 根據規劃設定主機名
hostnamectl set-hostname <hostname>
# 在master新增hosts 只在master中執行
cat >> /etc/hosts << EOF
192.168.72.131 k8s-master
192.168.72.129 k8s-node1
192.168.72.130 k8s-node2
EOF
# 將橋接的 IPv4 流量傳遞到 iptables 的鏈
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system # 生效
# 時間同步
yum install ntpdate -y
ntpdate time.windows.com
- 所有節點安裝 Docker/kubeadm/kubelet
安裝docker
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
yum -y install docker-ce-18.06.1.ce-3.el7
systemctl enable docker && systemctl start docker
docker --version
新增阿里雲 YUM 軟體源
# 設定倉庫地址
cat > /etc/docker/daemon.json << EOF
{
"registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
}
EOF
systemctl restart docker #重啟
# 新增 yum 源
cat > /etc/yum.repos.d/kubernetes.repo << EOF
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
安裝 kubeadm，kubelet 和 kubectl
#由於版本更新頻繁，這裡指定版本
yum install -y kubelet-1.18.0 kubeadm-1.18.0 kubectl-1.18.0
systemctl enable kubelet
- 部署 Kubernetes Master
在master上執行
kubeadm init --apiserver-advertise-address=192.168.72.131 --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.18.0 --service-cidr=10.96.0.0/12 --pod-network-cidr=10.244.0.0/16
由於預設拉取映象地址 k8s.gcr.io 國內無法訪問，這裡指定阿里雲映象倉庫地址。
使用 kubectl 工具：
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
kubectl get nodes
- 加入 Kubernetes Node
在 Node 中執行
向叢集新增新節點，執行在 kubeadm init 輸出的 kubeadm join 命令：
kubeadm join 192.168.72.131:6443 --token n0nyws.8j0mkjbfwk16adai \
--discovery-token-ca-cert-hash sha256:774e4171fc2a86bff58b49aaf153276f1fff56e93f1ba72e29a4ce3df8
預設token有效期為24小時，當過期之後，該token就不可用了。這時就需要重新建立token
# master 檢視節點檢查token是否有效
kubeadm token list
# 生成新的token和命令。然後在node重新執行
kubeadm token create --print-join-command
# 在 node節點執行新的token和命令
kubeadm join 192.168.136.201:6443 --token 17wwni.taqxzqa3our1wh92 --discovery-token-ca-cert-hash sha256:1472821b3c34f13bc5d7264a737739e9854195b1856a00d2256c79d25118b2e
123456
- 部署CNI網路外掛
kubectl apply –f
https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kubeflannel.yml
透過以上命令，部署CNI失敗，試了好多次仍然不成功，試試下面這種辦法。
①master檔案中建立檔案，將下述內容粘到檔案中，然後進行後續安裝。
vim kube-flannel.yml
---
---
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-plugin
image: rancher/mirrored-flannelcni-flannel-cni-plugin:v1.0.0
command:
- cp
args:
- -f
- /flannel
- /opt/cni/bin/flannel
volumeMounts:
- name: cni-plugin
mountPath: /opt/cni/bin
- name: install-cni
image: quay.io/coreos/flannel:v0.15.1
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:v0.15.1
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-plugin
hostPath:
path: /opt/cni/bin
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
②部署：
kubectl apply -f kube-flannel.yml
③執行如下命令，就會看到節點狀態為ready
kubectl get pods -n kube-system
kubectl get nodes
- 測試 kubernetes 叢集
在 Kubernetes 叢集中建立一個 pod，驗證是否正常執行：
kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --type=NodePort
kubectl get pod,svc
執行kubectl get pod,svc後，有一個埠號，在瀏覽器輸入任意一個node的IP加上這個埠號，能訪問nginx說明搭建成功。