kubeadmin搭建k8s集群

一、准備環境

准備環境：

角色	IP地址
k8s-master	192.168.56.21
k8s-node01	192.168.56.25
k8s-node02	192.168.56.26

所有節點環境初始化：

關閉防火牆：
systemctl stop firewalld
systemctl disable firewalld

關閉selinux：
sed -i 's/enforcing/disabled/' /etc/selinux/config
setenforce 0

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

按IP分別設置主機名：
hostnamectl set-hostname k8s-master
hostnamectl set-hostname k8s-node01
hostnamectl set-hostname k8s-node02

僅在master添加hosts：
cat >> /etc/hosts << EOF
192.168.56.21 k8s-master
192.168.56.25 k8s-node01
192.168.56.26 k8s-node02
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

時間同步：
yum install ntpdate -y
ntpdate time.windows.com
echo "*/5 * * * * /usr/sbin/ntpdate time.windows.com" >>/var/spool/cron/root 

二、在所有節點安裝Docker、kubeadm、kubectl、kubelet

2.1 安裝docker

wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
yum install -y yum-utils device-mapper-persistent-data lvm2
yum -y install docker-ce
systemctl enable docker && systemctl start docker

2.2 配置阿里雲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

2.3 三個節點安裝kubeadmin、kubelet，僅在k8s-master節點上安裝kubectl

yum install -y kubelet-1.19.0 kubeadm-1.19.0 kubectl-1.19.0
systemctl enable kubelet

 三、部署kubernetes master

kubeadm init \
  --apiserver-advertise-address=192.168.56.21 \
  --image-repository registry.aliyuncs.com/google_containers \
  --kubernetes-version v1.19.0 \
  --service-cidr=10.96.0.0/12 \
  --pod-network-cidr=10.244.0.0/16 \
  --ignore-preflight-errors=all

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

#  kubeadm init \
>   --apiserver-advertise-address=192.168.56.21 \
>   --image-repository registry.aliyuncs.com/google_containers \
>   --kubernetes-version v1.19.0 \
>   --service-cidr=10.96.0.0/12 \
>   --pod-network-cidr=10.244.0.0/16 \
>   --ignore-preflight-errors=all
W1005 15:41:47.137328   25574 configset.go:348] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
[init] Using Kubernetes version: v1.19.0
[preflight] Running pre-flight checks  # 檢查環境
    [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
    [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.9. Latest validated version: 19.03
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/etc/kubernetes/pki"  # 生成k8s和etcd證書
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [k8s-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.56.21]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.56.21 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.56.21 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"  # 生成kubeconfig文件 
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"  # 生成kubelet配置文件 
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Starting the kubelet
[control-plane] Using manifest folder "/etc/kubernetes/manifests"  # 部署管理節點組件，用鏡像啟動 kubectl get pod -n kube-system
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"  # 部署etcd數據庫用鏡像啟動
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 14.006837 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace  # 上傳配置文件到k8s中
[kubelet] Creating a ConfigMap "kubelet-config-1.19" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --upload-certs
[mark-control-plane] Marking the node k8s-master as control-plane by adding the label "node-role.kubernetes.io/master=''"  # 給管理節點打一個標簽
[mark-control-plane] Marking the node k8s-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]  # 將給管理節點打一個污點
[bootstrap-token] Using token: 46x35t.q5wjyktnsjdeu7gk  # 自動為kubelet頒發證書
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to get nodes
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[addons] Applied essential addon: CoreDNS  # 部署插件coredns和kube-proxy
[addons] Applied essential addon: kube-proxy

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

# 接下來需要在master執行的命令
  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

# 還需要部署一個網絡組件
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/

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

# 將node節點加入master的命令 
kubeadm join 192.168.56.21:6443 --token 46x35t.q5wjyktnsjdeu7gk \
    --discovery-token-ca-cert-hash sha256:8d44716e10fc9c16a45cb988cee767f0d4e59f1885e71914cc0ad94ba065aaf4 

初始化報錯解決方法

[kubelet-check] Initial timeout of 40s passed.
error execution phase upload-config/kubelet: Error writing Crisocket information for the control-plane node: timed out waiting for the condition

解決方法：
swapoff -a && kubeadm reset  && systemctl daemon-reload && systemctl restart kubelet  && iptables -F && iptables -t nat -F && iptables -t mangle -F && iptables -X

四、將node節點加入k8s集群中

]# kubeadm join 192.168.56.21:6443 --token 46x35t.q5wjyktnsjdeu7gk \
>     --discovery-token-ca-cert-hash sha256:8d44716e10fc9c16a45cb988cee767f0d4e59f1885e71914cc0ad94ba065aaf4 
[preflight] Running pre-flight checks
    [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
    [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.9. Latest validated version: 19.03
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

默認token有效期為24小時，當過期之后，該token就不可用了。這時就需要重新創建token，操作如下：

[root@k8s-master ~]# kubeadm token create
W1005 16:00:31.481430   31411 configset.go:348] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
i376x3.lw9aepx6ldbzrj5c
[root@k8s-master ~]# kubeadm token list
TOKEN                     TTL         EXPIRES                     USAGES                   DESCRIPTION             EXTRA GROUPS
i376x3.lw9aepx6ldbzrj5c   23h         2021-10-06T16:00:31+08:00   authentication,signing   <none>                  system:bootstrappers:kubeadm:default-node-token
[root@k8s-master ~]# openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'
8d44716e10fc9c16a45cb988cee767f0d4e59f1885e71914cc0ad94ba065aaf4
[root@k8s-master ~]# kubeadm join 192.168.56.21:6443 --token i376x3.lw9aepx6ldbzrj5c \
--discovery-token-ca-cert-hash sha256:8d44716e10fc9c16a45cb988cee767f0d4e59f1885e71914cc0ad94ba065aaf4

或者直接用命令生成也可以

kubeadm token create --print-join-command

五、部署網絡組件（CNI）

此時查看node節點是NotReady狀態

# kubectl get node
NAME         STATUS     ROLES    AGE   VERSION
k8s-master   NotReady   master   27m   v1.19.0
k8s-node01   NotReady   <none>   12m   v1.19.0
k8s-node02   NotReady   <none>   12m   v1.19.0

https://kubernetes.io/docs/concepts/cluster-administration/addons/

注意：只需要部署下面其中一個，推薦Calico。
Calico是一個純三層的數據中心網絡方案，Calico支持廣泛的平台，包括Kubernetes、OpenStack等。
Calico 在每一個計算節點利用 Linux Kernel 實現了一個高效的虛擬路由器（ vRouter） 來負責數據轉發，而每個 vRouter 通過 BGP 協議負責把自己上運行的 workload 的路由信息向整個 Calico 網絡內傳播。

 https://docs.projectcalico.org/getting-started/kubernetes/quickstart

wget https://docs.projectcalico.org/manifests/calico.yaml --no-check-certificate

下載完后還需要修改里面定義Pod網絡（CALICO_IPV4POOL_CIDR），與前面kubeadm init指定的一樣

# vim calico.yaml

 修改后

 當calico的pod都啟動成功之后，node節點就會變成ready狀態

# kubectl get pod -n kube-system -l k8s-app=calico-node -o wide
NAME                READY   STATUS     RESTARTS   AGE     IP              NODE         NOMINATED NODE   READINESS GATES
calico-node-4dcl8   1/1     Running    0          12m     192.168.56.25   k8s-node01   <none>           <none>
calico-node-kjs86   1/1     Running    0          12m     192.168.56.26   k8s-node02   <none>           <none>

# kubectl get node
NAME         STATUS   ROLES    AGE   VERSION
k8s-master   Ready    master   39m   v1.19.0
k8s-node01   Ready    <none>   24m   v1.19.0
k8s-node02   Ready    <none>   24m   v1.19.0

將kube-proxy改為ipvs，因為在初始化集群的時候注釋了ipvs配置，所以需要自行修改一下

# 在master節點執行
# kubectl edit cm kube-proxy -n kube-system
    mode: "ipvs"

# 更新kube-proxy的pod
# kubectl patch daemonset kube-proxy -p "{\"spec\":{\"template\":{\"metadata\":{\"annotations\":{\"date\":\"`date +'%s'`\"}}}}}" -n kube-system

# 驗證
# curl 127.0.0.1:10249/proxyMode
ipvs

六、部署Dashboard

官方GitHub地址：https://github.com/kubernetes/dashboard

6.1 創建管理員用戶

# cat admin.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding 
metadata: 
  name: admin-user
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: admin-user
  namespace: kube-system

# kubectl apply -f admin.yaml 

6.2 部署dashboard

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.4.0/aio/deploy/recommended.yaml

kubectl edit svc kubernetes-dashboard -n kubernetes-dashboard

將type類型由ClusterIP修改為NodePort類型

 查看nodeport端口

# kubectl get svc -n kubernetes-dashboard
NAME                        TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)         AGE
dashboard-metrics-scraper   ClusterIP   10.96.158.70     <none>        8000/TCP        154m
kubernetes-dashboard        NodePort    10.108.197.195   <none>        443:30612/TCP   154m

 使用node節點的IP:30612登錄dashboard

 查看admin用戶的token登錄dashboard

# kubectl get secret -n kube-system | grep admin-user
admin-user-token-qxvpl                           kubernetes.io/service-account-token   3      8m25s
# kubectl describe secret -n kube-system admin-user-token-qxvpl
Name:         admin-user-token-qxvpl
Namespace:    kube-system
Labels:       <none>
Annotations:  kubernetes.io/service-account.name: admin-user
              kubernetes.io/service-account.uid: 889b134a-a6e3-4306-999e-3a19cb91d95a

Type:  kubernetes.io/service-account-token

Data
====
ca.crt:     1066 bytes
namespace:  11 bytes
token:      eyJhbGciOiJSUzI1NiIsImtpZCI6InI3ODFQaTBzR19OeUpMQnhNQm5Lem5GSlpjZ0VzWXNITGY5dHI2bVlOUjgifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJhZG1pbi11c2VyLXRva2VuLXF4dnBsIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6ImFkbWluLXVzZXIiLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC51aWQiOiI4ODliMTM0YS1hNmUzLTQzMDYtOTk5ZS0zYTE5Y2I5MWQ5NWEiLCJzdWIiOiJzeXN0ZW06c2VydmljZWFjY291bnQ6a3ViZS1zeXN0ZW06YWRtaW4tdXNlciJ9.BHgiNSelW14pijLcO9BPP0WVkNT6--63CobSoG-eEydPfEhmQRSCmmkzFb9pmk3r0C9HURfmHlZ-FkEPs4RSolraso28iCbGz3xF-rwQ6e6HfpP6s5d3-i_yQJR74bIlkxKfYgZvMscmYu_1UP1PEuwnGQoBhhedGOMHnsFRNX4Fmzi50IitTHtef9ZzSCMDwmwZtOomybH0NpW2eTKHPINvou-NQaHSEhn38V14KgpeB8siPoSlxHrbEn9a-bKilWsU8XQakpWCvV5FImD6np1aMwLj-wIi7Y85Y1u19ieu5E1ovayY5al8fINjY1beLjHCLQfCp1qiQt_lMB2DcA