使用 Kubernetes REST API 来操作K8S各种资源 k8s kubelet 作用

k8s集群安装手册

• 说明

• 目标
• 准备环境
• 所有节点安装docker/kubelet/kubeadm/kubectl
• 部署k8s master
• 安装网络组件calico
• Node节点加入k8s master
• 测试集群是否正常
• 部署k8s默认Dashboard

说明

你好，下文是教你一步一步安装k8s集群，本文适合刚入门k8s的伙伴，不建议用于生产环境的搭建，仅供测试~

目标

• 所有主机安装docker和k8s软件
• 部署k8s Master
• 部署容器网络插件
• Node加入k8s集
• 部署dashboard

准备环境

准备3台主机进行集群搭建测试
172.16.19.96 k8s-master
172.16.19.171 k8s-node1
172.16.19.172 k8s-node2

1. 关闭主机防火墙

systemctl stop firewalld  
systemctl disable firewalld 
systemctl stop iptables
systemctl disable iptables

2. 关闭selinux

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

3. 关闭swap

swapoff -a 临时
vim /etc/fstab  永久

4. 配置主机名和hosts

hostname k8s-master
hostname k8s-node1
hostname k8s-node2

vim /etc/hosts
172.16.19.96   k8s-master
172.16.19.171  k8s-node1
172.16.19.172  k8s-node2

5. 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

echo '1' > /proc/sys/net/ipv4/ip_forward

所有节点安装docker/kubelet/kubeadm/kubectl

• docker安装

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

• k8s组件安装

k8s 阿里yum源
cat > /etc/yum.repos.d/kubernetes.repo  << EOF
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
        http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
#可以先看下支持列表
yum --enablerepo=kubernetes list kubelet kubeadm kubectl --showduplicates | sort -r
#安装指定版本
yum --enablerepo=kubernetes install kubelet-1.16.9-0 kubeadm-1.16.9-0 kubectl-1.16.9-0

部署k8s master

• k8s 初始化配置文件

导出默认配置文件
kubeadm config print init-defaults >  kubeadm-v3.conf
修改默认镜像地址： vi kubeadm-v3.conf
#指向阿里源，能科学上网就不用改
imageRepository: registry.aliyuncs.com/google_containers
#通过配置文件提前拉取镜像
kubeadm config images pull --config kubeadm-v3.conf

配置文件请参考链接:https://pan.baidu.com/s/1zcRmtss3EjTDuRnFzA4bJA 密码:h8pg

• 集群初始化

#使用配置文件拉取镜像
kubeadm config images pull --config kubeadm-v3.conf
#使用配置文件初始化集群
kubeadm init   --config kubeadm-v3.conf

• 成功后输出：

[root@c2-master1 kubeadm]# kubeadm init   --config kubeadm-v3.conf
[init] Using Kubernetes version: v1.16.9
[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: 19.03.9. Latest validated version: 18.09
[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] Activating the kubelet service
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [c2-master1 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local k8s-api-c2.ops.geekplus.cc c2-master1 c2-master2 c2-master3] and IPs [10.96.0.1 172.16.19.105 172.16.19.239 127.0.0.1 172.16.19.105 172.16.19.106 172.16.19.108 172.16.19.239]
[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] External etcd mode: Skipping etcd/ca certificate authority generation
[certs] External etcd mode: Skipping etcd/server certificate generation
[certs] External etcd mode: Skipping etcd/peer certificate generation
[certs] External etcd mode: Skipping etcd/healthcheck-client certificate generation
[certs] External etcd mode: Skipping apiserver-etcd-client certificate generation
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[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
[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"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[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 21.522694 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.16" 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 c2-master1 as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node c2-master1 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: abcdef.0123456789abcdef
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
      1 Your Kubernetes control-plane has initialized successfully!
[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
[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/

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 172.16.19.96:6443 --token abcdef.0123456789abcdef --discovery-token-ca-cert-hash sha256:3610643b232a0c536ef2cac74f4ca7b836dd5d8500d52045934f5be92c447535  --control-plane

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

kubeadm join 172.16.19.239:6443 --token abcdef.0123456789abcdef \
    --discovery-token-ca-cert-hash sha256:9aa544afc7007ee55f51a8d531bcd83960096ed28ba9f9ea360f68385bf4ff90

• 拷贝授权配置文件

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
###其他节点加入集群
master:  kubeadm join xxxx --control-plane 参数中带控制面板
node: 没有控制板参数

• 查看当前集群情况

kubectl get nodes

安装网络组件calico

wget wget https://kuboard.cn/install-script/calico/calico-3.9.2.yaml 
kubectl apply -f calico-3.9.2.yaml
#需要确保calico-3.9.2.yaml和kubeadm-v3.conf 配置的CALICO_IPV4POOL_CIDR相同

配置文件请参考链接:https://pan.baidu.com/s/10_qigXeUshq8NtLXOG-ETQ 密码:34py

Node节点加入k8s master

• 添加Master主机

同步证书/etc/kubernetes/pki/到需要做master的其他节点同路径下
scp -r /etc/kubernetes/pki/ root@172.16.19.108:/etc/kubernetes/
scp -r /etc/kubernetes/pki/ root@172.16.19.106:/etc/kubernetes/
执行join命令
kubeadm join 172.16.19.96:6443 --token abcdef.0123456789abcdef --discovery-token-ca-cert-hash sha256:3610643b232a0c536ef2cac74f4ca7b836dd5d8500d52045934f5be92c447535  --control-plane
安装网络组件
kubectl apply -f calico-3.9.2.yaml
#需要确保calico-3.9.2.yaml和kubeadm-v3.conf 配置的CALICO_IPV4POOL_CIDR相同
确认网络组件启动成功
kubectl get po -n kube-system |grep calico
确认节点加入成功
kubectl get nodes

• 添加Worker主机

kubeadm join 172.16.19.96:6443 --token abcdef.0123456789abcdef --discovery-token-ca-cert-hash sha256:3610643b232a0c536ef2cac74f4ca7b836dd5d8500d52045934f5be92c447535
到master节点查看确认是否加入成功
kubectl get nodes

测试集群是否正常

部署一个nginx来测试一下集群是否正常

在k8s集群创建一个pod
kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --type=NodePort
kubectl get pod,svc
访问地址http://NodeIP:Port

部署k8s默认Dashboard

官方参考文档： https://kubernetes.io/docs/tasks/access-application-cluster/web-ui-dashboard/ github项目地址： https://github.com/kubernetes/dashboard
当前部署dashboard版本：v2.0.0，注意检查dashboard版本与kubernetes版本兼容性：
https://github.com/kubernetes/dashboard/releases

• 执行yaml文件直接部署：

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0/aio/deploy/recommended.yaml

• 查看dashboard运行状态，以deployment方式部署，运行2个pod及2个service：

kubectl -n kubernetes-dashboard get pods
kubectl -n kubernetes-dashboard get svc

• 访问dashboard

这里作为演示，使用nodeport方式将dashboard服务暴露在集群外，指定使用30443端口，可自定义：
kubectl  patch svc kubernetes-dashboard -n kubernetes-dashboard -p '{"spec":{"type":"NodePort","ports":[{"port":443,"targetPort":8443,"nodePort":30443}]}}'

• 查看暴露的service,已修改为nodeport类型：

kubectl -n kubernetes-dashboard get svc

• 或者下载yaml文件手动修改service部分

$ wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-beta8/aio/deploy/recommended.yaml
#修改servcie部分
$ more recommended.yaml
...
---
kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kubernetes-dashboard
spec:
  type: NodePort
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 30443
  selector:
    k8s-app: kubernetes-dashboard

---
...

• 更新配置

kubectl apply -f recommended.yaml

• 登录dashboard

浏览器访问dashboard：
https://<any_node_ip>:30443

Dashboard 支持 Kubeconfig 和 Token 两种认证方式，我们这里选择Token认证方式登录。
官方参考文档: https://github.com/kubernetes/dashboard/blob/master/docs/user/access-control/creating-sample-user.md

创建dashboard-adminuser.yaml：
cat > dashboard-adminuser.yaml << EOF
apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kubernetes-dashboard

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: admin-user
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
 - kind: ServiceAccount
  name: admin-user
  namespace: kubernetes-dashboard  
EOF

• 创建登录用户

kubectl apply -f dashboard-adminuser.yaml

说明：上面创建了一个叫admin-user的服务账号，并放在kubernetes-dashboard 命名空间下，并将cluster-admin角色绑定到admin-user账户，这样admin-user账户就有了管理员的权限。默认情况下，kubeadm创建集群时已经创建了cluster-admin角色，我们直接绑定即可。

• 查看admin-user账户的token

kubectl -n kubernetes-dashboard describe secret $(kubectl -n kubernetes-dashboard get secret | grep admin-user | awk '{print $1}')

把获取到的Token复制到登录界面的Token输入框中，成功登陆dashboard