centos8默认安装了podman容器，它和docker可能有冲突需要卸载掉
sudo yum remove podman将如下内容保存到：/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由于目前阿里镜像中还没有CentOS8的kubernetes，但是可以使用CentOS7的安装包，所以上面是使用的kubernetes-el7-x86_64，如果有CentOS8的，则为kubernetes-el8-x86_64。
如果出现错误：
错误： 问题: package docker-ce-3:19.03.8-3.el7.x86_64 requires containerd.io >= 1.2.2-3, but none of the providers can be installed - cannot install the best candidate for the job - package containerd.io-1.2.10-3.2.el7.x86_64 is excluded - package containerd.io-1.2.13-3.1.el7.x86_64 is excluded - package containerd.io-1.2.2-3.3.el7.x86_64 is excluded - package containerd.io-1.2.2-3.el7.x86_64 is excluded - package containerd.io-1.2.4-3.1.el7.x86_64 is excluded - package containerd.io-1.2.5-3.1.el7.x86_64 is excluded - package containerd.io-1.2.6-3.3.el7.x86_64 is excluded (尝试添加 '--skip-broken' 来跳过无法安装的软件包 或 '--nobest' 来不只使用最佳选择的软件包)可以通过如下方式来解决：
wget https://download.docker.com/linux/centos/7/x86_64/edge/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm yum install containerd.io-1.2.6-3.3.el7.x86_64.rpm为了docker加速pull，可以设置阿里云加速：
sudo mkdir -p /etc/docker sudo vim /etc/docker/daemon.json设置为如下内容：
{ "registry-mirrors" : ["https://mj9kvemk.mirror.aliyuncs.com"] }安装kubectl、kubelet、kubeadm，设置kubelet开机启动，启动kubelet。
sudo yum install -y kubectl kubelet kubeadm sudo systemctl enable kubelet sudo systemctl start kubelet查看K8S版本
kubeadm version kubectl version --client kubelet --version可以看到kubelet的版本为1.18.5。
运行后出现问题：
[root@localhost admin]# kubeadm init --apiserver-advertise-address=0.0.0.0 \ --apiserver-cert-extra-sans=127.0.0.1 \ --image-repository=registry.aliyuncs.com/google_containers \ --ignore-preflight-errors=all \ --kubernetes-version=v1.18.5 \ --service-cidr=10.10.0.0/16 \ --pod-network-cidr=10.18.0.0/16 W0702 16:23:11.951553 16395 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io] [init] Using Kubernetes version: v1.18.5 [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/ [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' [WARNING IsDockerSystemdCheck]: detected “cgroupfs” as the Docker cgroup driver. The recommended driver is “systemd”. 出现[WARNING IsDockerSystemdCheck]，是由于docker的Cgroup Driver和kubelet的Cgroup Driver不一致导致的，此处选择修改docker的和kubelet一致查看docker信息：
docker info | grep Cgroup可以看到驱动为Cgroup，需要改为systemd。 编辑文件/usr/lib/systemd/system/docker.service 在ExecStart命令中添加
--exec-opt native.cgroupdriver=systemd然后重启docker，再查看信息，可以看到已经变为systemd了
systemctl daemon-reload systemctl restart docker docker info | grep Cgroup此时再执行下面的命令进行初始化：
kubeadm init --apiserver-advertise-address=0.0.0.0 \ --apiserver-cert-extra-sans=127.0.0.1 \ --image-repository=registry.aliyuncs.com/google_containers \ --ignore-preflight-errors=all \ --kubernetes-version=v1.18.5 \ --service-cidr=10.10.0.0/16 \ --pod-network-cidr=10.18.0.0/16由于kubeadm 默认从官网k8s.grc.io下载所需镜像，国内无法访问，因此需要通过–image-repository指定阿里云镜像仓库地址。 但是还是出现问题：
kubeadm init --apiserver-advertise-address=0.0.0.0 --apiserver-cert-extra-sans=127.0.0.1 --image-repository=registry.aliyuncs.com/google_containers --ignore-preflight-errors=all --kubernetes-version=v1.18.5 --service-cidr=10.10.0.0/16 --pod-network-cidr=10.18.0.0/16 W0702 17:47:00.104450 61229 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io] [init] Using Kubernetes version: v1.18.5 [preflight] Running pre-flight checks [WARNING FileAvailable--etc-kubernetes-manifests-kube-apiserver.yaml]: /etc/kubernetes/manifests/kube-apiserver.yaml already exists [WARNING FileAvailable--etc-kubernetes-manifests-kube-controller-manager.yaml]: /etc/kubernetes/manifests/kube-controller-manager.yaml already exists [WARNING FileAvailable--etc-kubernetes-manifests-kube-scheduler.yaml]: /etc/kubernetes/manifests/kube-scheduler.yaml already exists [WARNING FileAvailable--etc-kubernetes-manifests-etcd.yaml]: /etc/kubernetes/manifests/etcd.yaml already exists [WARNING Port-10250]: Port 10250 is in use [WARNING Port-2379]: Port 2379 is in use [WARNING Port-2380]: Port 2380 is in use [WARNING DirAvailable--var-lib-etcd]: /var/lib/etcd is not empty [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' [WARNING ImagePull]: failed to pull image registry.aliyuncs.com/google_containers/kube-apiserver:v1.18.5: output: Error response from daemon: manifest for registry.aliyuncs.com/google_containers/kube-apiserver:v1.18.5 not found: manifest unknown: manifest unknown , error: exit status 1 [WARNING ImagePull]: failed to pull image registry.aliyuncs.com/google_containers/kube-controller-manager:v1.18.5: output: Error response from daemon: manifest for registry.aliyuncs.com/google_containers/kube-controller-manager:v1.18.5 not found: manifest unknown: manifest unknown , error: exit status 1 [WARNING ImagePull]: failed to pull image registry.aliyuncs.com/google_containers/kube-scheduler:v1.18.5: output: Error response from daemon: manifest for registry.aliyuncs.com/google_containers/kube-scheduler:v1.18.5 not found: manifest unknown: manifest unknown , error: exit status 1 [WARNING ImagePull]: failed to pull image registry.aliyuncs.com/google_containers/kube-proxy:v1.18.5: output: Error response from daemon: manifest for registry.aliyuncs.com/google_containers/kube-proxy:v1.18.5 not found: manifest unknown: manifest unknown , error: exit status 1 [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [kubelet-start] Starting the kubelet [certs] Using certificateDir folder "/etc/kubernetes/pki" [certs] Using existing ca certificate authority [certs] Using existing apiserver certificate and key on disk [certs] Using existing apiserver-kubelet-client certificate and key on disk [certs] Using existing front-proxy-ca certificate authority [certs] Using existing front-proxy-client certificate and key on disk [certs] Using existing etcd/ca certificate authority [certs] Using existing etcd/server certificate and key on disk [certs] Using existing etcd/peer certificate and key on disk [certs] Using existing etcd/healthcheck-client certificate and key on disk [certs] Using existing apiserver-etcd-client certificate and key on disk [certs] Using the existing "sa" key [kubeconfig] Using kubeconfig folder "/etc/kubernetes" [kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/admin.conf" [kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/kubelet.conf" [kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/controller-manager.conf" [kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/scheduler.conf" [control-plane] Using manifest folder "/etc/kubernetes/manifests" [control-plane] Creating static Pod manifest for "kube-apiserver" [control-plane] Creating static Pod manifest for "kube-controller-manager" W0702 17:47:17.258210 61229 manifests.go:225] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC" [control-plane] Creating static Pod manifest for "kube-scheduler" W0702 17:47:17.261156 61229 manifests.go:225] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC" [etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests" [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应该是阿里云镜像中还没有1.18.5的相关文件，改为1.18.2试试：
kubeadm init --apiserver-advertise-address=0.0.0.0 --apiserver-cert-extra-sans=127.0.0.1 --image-repository=registry.aliyuncs.com/google_containers --ignore-preflight-errors=all --kubernetes-version=v1.18.2 --service-cidr=10.10.0.0/16 --pod-network-cidr=10.18.0.0/16成功了：
[root@localhost admin]# kubeadm init --apiserver-advertise-address=0.0.0.0 --apiserver-cert-extra-sans=127.0.0.1 --image-repository=registry.aliyuncs.com/google_containers --ignore-preflight-errors=all --kubernetes-version=v1.18.2 --service-cidr=10.10.0.0/16 --pod-network-cidr=10.18.0.0/16 W0702 17:47:41.592876 62703 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io] [init] Using Kubernetes version: v1.18.2 [preflight] Running pre-flight checks [WARNING FileAvailable--etc-kubernetes-manifests-kube-apiserver.yaml]: /etc/kubernetes/manifests/kube-apiserver.yaml already exists [WARNING FileAvailable--etc-kubernetes-manifests-kube-controller-manager.yaml]: /etc/kubernetes/manifests/kube-controller-manager.yaml already exists [WARNING FileAvailable--etc-kubernetes-manifests-kube-scheduler.yaml]: /etc/kubernetes/manifests/kube-scheduler.yaml already exists [WARNING FileAvailable--etc-kubernetes-manifests-etcd.yaml]: /etc/kubernetes/manifests/etcd.yaml already exists [WARNING Port-10250]: Port 10250 is in use [WARNING Port-2379]: Port 2379 is in use [WARNING Port-2380]: Port 2380 is in use [WARNING DirAvailable--var-lib-etcd]: /var/lib/etcd is not empty [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' [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [kubelet-start] Starting the kubelet [certs] Using certificateDir folder "/etc/kubernetes/pki" [certs] Using existing ca certificate authority [certs] Using existing apiserver certificate and key on disk [certs] Using existing apiserver-kubelet-client certificate and key on disk [certs] Using existing front-proxy-ca certificate authority [certs] Using existing front-proxy-client certificate and key on disk [certs] Using existing etcd/ca certificate authority [certs] Using existing etcd/server certificate and key on disk [certs] Using existing etcd/peer certificate and key on disk [certs] Using existing etcd/healthcheck-client certificate and key on disk [certs] Using existing apiserver-etcd-client certificate and key on disk [certs] Using the existing "sa" key [kubeconfig] Using kubeconfig folder "/etc/kubernetes" [kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/admin.conf" [kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/kubelet.conf" [kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/controller-manager.conf" [kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/scheduler.conf" [control-plane] Using manifest folder "/etc/kubernetes/manifests" [control-plane] Creating static Pod manifest for "kube-apiserver" [control-plane] Creating static Pod manifest for "kube-controller-manager" W0702 17:49:34.509168 62703 manifests.go:225] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC" [control-plane] Creating static Pod manifest for "kube-scheduler" W0702 17:49:34.510843 62703 manifests.go:225] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC" [etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests" [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 12.003628 seconds [upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace [kubelet] Creating a ConfigMap "kubelet-config-1.18" 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 localhost.localdomain as control-plane by adding the label "node-role.kubernetes.io/master=''" [mark-control-plane] Marking the node localhost.localdomain as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule] [bootstrap-token] Using token: l21jwf.pjzezg1xmopqoj0p [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 [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: mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config 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: kubeadm join 192.168.1.134:6443 --token l21jwf.pjzezg1xmopqoj0p \ --discovery-token-ca-cert-hash sha256:0b1062f2ec73f8c35c1bfecd857a287b128aba7ae5c0673ea604c9ac7c296a95执行提示中的命令：
mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config再执行：
kubectl get node kubectl get pod --all-namespacesnode节点为NotReady，因为coredns pod没有启动，缺少网络pod。
过一会再查看信息，节点已经处于Ready状态了。
将官方的recommended.yaml文件下载下来。可以使用下面的命令下载，如果国内无法访问https://raw.githubusercontent.com，则可以在前面的链接中复制内容再保存。
wget https://raw.githubusercontent.com/kubernetes/dashboard/master/aio/deploy/recommended.yaml由于官方没使用nodeport，所以需要修改文件，添加两行配置。
kind: Service apiVersion: v1 metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard namespace: kubernetes-dashboard spec: type: NodePort #添加这行 ports: - port: 443 targetPort: 8443 nodePort: 30000 #添加这行 selector: k8s-app: kubernetes-dashboard如图所示： 然后创建POD，并查看kubernetes-dashboard
kubectl create -f recommended.yaml kubectl get svc -n kubernetes-dashboard此时，可以使用浏览器访问：https://192.168.1.134:30000/#/login，其中的IP是本机的IP。
这里有两种登录方式：
使用Token登录使用Kubeconfig登录输入Token后，登录页面如下图所示： 需要注意的是Token默认有效期是24小时，过期需要重新生成token。
有了kubernetes-dashboard的帮助，就可以可视化的部署与监控应用了。
或者：
token=$(kubeadm token generate) kubeadm token create $token --print-join-command --ttl=0以部署nginx和mysql为例，介绍如何利用K8s DashBoard部署容器。
在Web页面依次按下图操作 在点击“Deploy"后等待一段时间，当状态颜色都变为绿色则表示成功。 在此步可能会出现错误：
0/1 nodes are available: 1 node(s) had taints that the pod didn't tolerate.这是因为k8s出于安全考虑默认情况下无法在master节点上部署pod，在Linux控制台执行下面的命令解决：
kubectl taint nodes --all node-role.kubernetes.io/master-还有可能出现错误：
Back-off restarting failed container在deployment申明镜像的后面加上命令 command: [ “/bin/bash”, “-ce”, “tail -f /dev/null” ] 成功页面： 然后在下面找到“Services”栏，可以看到暴露给外部的端口，此时我们可以使用这个端口访问nginx了。 看到nginx的欢迎页面，说明成功了。
与部署nginx类似，但是有一点不一样的就是Mysql的容器需要指定一个初始化的密码，所以需要用到“高级选项”： 在高级选项中填入环境变量： 名字：MYSQL_ROOT_PASSWORD 值：123456 这样就设置了Mysql的root账号密码。 部署成功后可以试试Mysql： 可以看到成功访问Mysql。 我再试试外部访问，首先查看对外端口：
如果想要删除已经部署的容器，可以在页面中点下图所示按钮，在弹出的菜单中选择删除即可。 参考： https://blog.csdn.net/vs2008ASPNET/article/details/104119331/ https://blog.csdn.net/sq4521/article/details/105873575 https://www.kubernetes.org.cn/7189.html https://www.ywcsb.vip/blog/94.html
