快速部署一个Kubernetes集群

官方提供的三种部署方式

minikube

Minikube是一个工具，可以在本地快速运行一个单点的Kubernetes，仅用于尝试Kubernetes或日常开发的用户使用。

部署地址：https://kubernetes.io/docs/setup/minikube/

kubeadm

Kubeadm也是一个工具，提供kubeadm init和kubeadm join，用于快速部署Kubernetes集群。

部署地址：https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm/

二进制

推荐，从官方下载发行版的二进制包，手动部署每个组件，组成Kubernetes集群。

下载地址：https://github.com/kubernetes/kubernetes/releases

1. 安装要求

在开始之前，部署Kubernetes集群机器需要满足以下几个条件：

- 一台或多台机器，操作系统 CentOS7.x-86_x64
- 硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘30GB或更多
- 集群中所有机器之间网络互通
- 可以访问外网，需要拉取镜像
- 禁止swap分区

2. 学习目标

1. 在所有节点上安装Docker和kubeadm
2. 部署Kubernetes Master
3. 部署容器网络插件
4. 部署 Kubernetes Node，将节点加入Kubernetes集群中
5. 部署Dashboard Web页面，可视化查看Kubernetes资源

3. 准备环境

关闭防火墙：

systemctl stop firewalld

systemctl disable firewalld

关闭selinux：

sed -i 's/enforcing/disabled/' /etc/selinux/config

setenforce

关闭swap：

swapoff -a # 临时

vim /etc/fstab # 永久

添加主机名与IP对应关系）：

cat /etc/hosts

192.168.140.130 k8s-master

192.168.140.131 k8s-node1

192.168.140.132 k8s-node2

设置Maeter/node1/node2主机名：

hostnamectl set-hostname k8s-master

hostnamectl set-hostname k8s-node1

hostnamectl set-hostname k8s-node2

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 =

net.bridge.bridge-nf-call-iptables =

EOF

sysctl --system

设置时间同步

yum -y install ntpdate

ntpdate time.windows.com

4. 所有节点安装Docker/kubeadm/kubelet

Kubernetes默认CRI（容器运行时）为Docker，因此先安装Docker。

4.1 安装Docker

每台机器上安装Docker，建议使用18.09版本。

wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo

yum list docker-ce --showduplicates | sort -r

yum -y install docker-ce-18.09.-.el7

设置cgroup驱动，推荐systemd：

 cat > /etc/docker/daemon.json <<EOF

{

  "exec-opts": ["native.cgroupdriver=systemd"],

  "log-driver": "json-file",

  "log-opts": {

    "max-size": "100m"

  },

  "storage-driver": "overlay2"

}

EOF

systemctl enable docker

systemctl start docker

镜像下载加速：

curl -sSL https://get.daocloud.io/daotools/set_mirror.sh | sh -s http://f1361db2.m.daocloud.io

因为追加过cgroup驱动的配置，运行以上命令加载静态加速会使daemon.json的格式不正确，修改为如下

{"registry-mirrors": ["http://f1361db2.m.daocloud.io"],

  "exec-opts": ["native.cgroupdriver=systemd"],

  "log-driver": "json-file",

  "log-opts": {"max-size": "100m"},

  "storage-driver": "overlay2"

}

重新加载

systemctl restart docker

4.2 添加阿里云YUM软件源

cat > /etc/yum.repos.d/kubernetes.repo << EOF

[kubernetes]

name=Kubernetes

baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64

enabled=

gpgcheck=

repo_gpgcheck=

gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg

EOF

4.3 安装kubeadm，kubelet和kubectl

由于版本更新频繁，这里指定版本号部署：

yum install -y kubelet-1.16. kubeadm-1.16. kubectl-1.16.

systemctl enable kubelet

5. 部署Kubernetes Master

在192.168.140.130（Master）执行。

 kubeadm init \

  --apiserver-advertise-address=192.168.140.130 \

  --image-repository registry.aliyuncs.com/google_containers \

  --kubernetes-version v1.16.0 \

  --service-cidr=10.1.0.0/ \

  --pod-network-cidr=10.244.0.0/

由于默认拉取镜像地址k8s.gcr.io国内无法访问，这里指定阿里云镜像仓库地址。

具体创建过程

[root@k8s-master ~]# kubeadm init   --apiserver-advertise-address=192.168.146.130   --image-repository registry.aliyuncs.com/google_containers   --kubernetes-version v1.16.0   --service-cidr=10.1.0.0/   --pod-network-cidr=10.244.0.0/

[init] Using Kubernetes version: v1.16.0

[preflight] Running pre-flight checks

[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 [k8s-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.1.0.1 192.168.146.130]

[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 [192.168.146.130 127.0.0.1 ::]

[certs] Generating "etcd/peer" certificate and key

[certs] etcd/peer serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.146.130 127.0.0.1 ::]

[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"

[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"

[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 37.002058 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 k8s-master as control-plane by adding the label "node-role.kubernetes.io/master=''"

[mark-control-plane] Marking the node k8s-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]

[bootstrap-token] Using token: z5w3q8.oodwazhy81hs0guy

[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles

[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/

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

kubeadm join 192.168.146.130: --token z5w3q8.oodwazhy81hs0guy \    #加入node需要验证的token

    --discovery-token-ca-cert-hash sha256:00573b2c69770af26f300158845535faf4fc4be4aab5470b245653a95e85ba0d

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

[root@k8s-master ~]# kubectl get node

NAME         STATUS   ROLES    AGE    VERSION

k8s-master   Ready    master   4m2s   v1.16.0

6. 安装Pod网络插件（CNI）

这个文件 kube-flannel.yaml 需要注意镜像地址、还有网络地址跟kubeadm init创建的地址要一致pod-network-cidr=10.244.0.0/16

文件预先已设置好，上传到master

https://pan.baidu.com/s/1kYIJXu5J2clmynXbsFZtpg提取码 bxhp

kubectl apply -f kube-flannel.yaml

kubectl get pods -n kube-system

[root@k8s-master ~]# kubectl get pods -n kube-system

NAME                                 READY   STATUS     RESTARTS   AGE

coredns-58cc8c89f4-2rplz             /     Pending              3m6s

coredns-58cc8c89f4-rqbpg             /     Pending              3m6s

etcd-k8s-master                      /     Running              2m26s

kube-apiserver-k8s-master            /     Running              2m13s

kube-controller-manager-k8s-master   /     Running              2m27s

kube-flannel-ds-amd64-l4gcz          /     Init:/             15s

kube-proxy-bhxc2                     /     Running              3m6s

kube-scheduler-k8s-master            /     Running              2m13s

7. 加入Kubernetes Node

在192.168.140.131/132（Node）执行。

向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：

kubeadm join 192.168.140.130: --token esce21.q6hetwm8si29qxwn \

    --discovery-token-ca-cert-hash sha256:00603a05805807501d7181c3d60b478788408cfe6cedefedb1f97569708be9c5

[root@k8s-master ~]# kubectl get node

NAME         STATUS   ROLES    AGE     VERSION

k8s-master   Ready    master   8m53s   v1.16.0

k8s-node1    Ready    <none>   3m31s   v1.16.0

k8s-node2    Ready    <none>   91s     v1.16.0

默认token有效期为24小时，当过期之后，该token就不可用了。这时就需要重新创建token，操作如下：

kubeadm token create

kubeadm token list

openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der >/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'

63bca849e0e01691ae14eab449570284f0c3ddeea590f8da988c07fe2729e924

kubeadm join 192.168.140.130: --discovery-token nuja6n.o3jrhsffiqs9swnu --discovery-token-ca-cert-hash 63bca849e0e01691ae14eab449570284f0c3ddeea590f8da988c07fe2729e924

```

<https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-join/>

8. 测试kubernetes集群

在Kubernetes集群中创建一个pod，验证是否正常运行：

kubectl create deployment web --image=nginx

kubectl expose deployment web --port= --target-port= --type=NodePort

[root@k8s-master ~]# kubectl get pods,svc

NAME                      READY   STATUS              RESTARTS   AGE

pod/web-d86c95cc9-9ktfn   /     ContainerCreating             83s

NAME                 TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)        AGE

service/kubernetes   ClusterIP   10.1.0.1      <none>        /TCP        11m

service/web          NodePort    10.1.87.160   <none>        :/TCP   19s

访问地址：http://NodeIP:Port

确保所有节点都能访问（master、node1、node2）

9. 部署 Dashboard

https://pan.baidu.com/s/1F4fHAas2fDPDgy8h-QS6KA提取码vb7o

  type: NodePort

  ports:

    - port:

      targetPort:

      nodePort:

这个yaml文件增加了一个类型NodePort，端口为30001，其它跟官方yaml一致

kubectl apply -f dashboard.yaml

kubectl get pods -n kubernetes-dashboard

访问地址：http://NodeIP:30001

创建service account并绑定默认cluster-admin管理员集群角色：

kubectl create serviceaccount dashboard-admin -n kubernetes-dashboard

kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kubernetes-dashboard:dashboard-admin

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

使用输出的token登录Dashboard。

查看资源利用率

可以查看当前pod的日志，可以进入容器里边操作，还可以扩容副本