Kubernetes 安装手册(Ubuntu非高可用版)

安装前准备工作

1. 设置hosts解析

操作节点:所有节点(k8s-master)均需执行

  • 修改hostname hostname必须只能包含小写字母、数字、","、"-",且开头结尾必须是小写字母或数字 ``` python

    在master节点

    $ hostnamectl set-hostname k8s-master #设置master节点的hostname
### 2. 调整系统配置
操作节点: 所有的master和slave节点(`k8s-master,k8s-slave`)需要执行

>本章下述操作均以k8s-master为例,其他节点均是相同的操作(ip和hostname的值换成对应机器的真实值)

**设置iptables**

``` python
$ iptables -P FORWARD ACCEPT
$ /etc/init.d/ufw stop
  • 关闭swap
    swapoff -a
    # 防止开机自动挂载 swap 分区
    sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
    
  • 修改内核参数
    cat <<EOF >  /etc/sysctl.d/k8s.conf
    net.bridge.bridge-nf-call-ip6tables = 1
    net.bridge.bridge-nf-call-iptables = 1
    net.ipv4.ip_forward=1
    vm.max_map_count=262144
    EOF
    modprobe br_netfilter
    sysctl -p /etc/sysctl.d/k8s.conf
    
  • 设置apt源
#替换apt源
$ vi /etc/apt/sources.list
deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse

$ apt-get update && apt-get install -y apt-transport-https ca-certificates software-properties-common 
$ curl https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add - 
$ curl -fsSL https://mirrors.ustc.edu.cn/docker-ce/linux/ubuntu/gpg | sudo apt-key add 
$ add-apt-repository "deb [arch=amd64] https://mirrors.ustc.edu.cn/docker-ce/linux/ubuntu $(lsb_release -cs) stable"
$ tee /etc/apt/sources.list.d/kubernetes.list <<-'EOF'
deb https://mirrors.aliyun.com/kubernetes/apt kubernetes-xenial main
EOF

$ apt-get update   
#若上步出现NO_PUBLICKEY问题,参考https://www.cnblogs.com/jiangzuo/p/13667011.html

3. 安装docker

操作节点: 所有节点

$ apt-get install docker-ce=5:19.03.9~3-0~ubuntu-bionic
## 启动docker
$ systemctl enable docker && systemctl start docker

部署kubernetes

1. 安装 kubeadm, kubelet 和 kubectl

操作节点: 所有的master和slave节点(k8s-master,k8s-slave) 需要执行

$ apt-get install kubelet=1.20.0-00 kubectl=1.20.0-00 kubeadm=1.20.0-00
## 查看kubeadm 版本
$ kubeadm version
## 设置kubelet开机启动
$ systemctl enable kubelet

2. 初始化配置文件

操作节点: 只在master节点(k8s-master)执行

$ kubeadm config print init-defaults > kubeadm.yaml
$ cat kubeadm.yaml
apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: abcdef.0123456789abcdef
  ttl: 24h0m0s
  usages:
  - signing
  - authentication
kind: InitConfiguration
localAPIEndpoint:
  advertiseAddress: 192.168.136.135   # 修改成master主机ip
  bindPort: 6443
nodeRegistration:
  criSocket: /var/run/dockershim.sock
  name: k8s-master
  taints:
  - effect: NoSchedule
    key: node-role.kubernetes.io/master
---
apiServer:
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns:
  type: CoreDNS
etcd:
  local:
    dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers   # 修改为国内源
kind: ClusterConfiguration
kubernetesVersion: v1.20.0    # 修改为v1.20.0
networking:
  dnsDomain: cluster.local
  podSubnet: 10.244.0.0/16            # 添加pod网段
  serviceSubnet: 10.96.0.0/12
scheduler: {}

3. 提前下载镜像

操作节点:只在master节点(k8s-master)执行

  # 提前下载镜像到本地
$ kubeadm config images pull --config kubeadm.yaml
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-apiserver:v1.20.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-controller-manager:v1.20.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-scheduler:v1.20.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-proxy:v1.20.0
[config/images] Pulled registry.aliyuncs.com/google_containers/pause:3.2
[config/images] Pulled registry.aliyuncs.com/google_containers/etcd:3.4.3-0
[config/images] Pulled registry.aliyuncs.com/google_containers/coredns:1.6.7

4. 初始化master节点

操作节点:只在master节点(k8s-master)执行

$ kubeadm init --config kubeadm.yaml

若初始化成功后,最后会提示如下信息:

...
Your Kubernetes master 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 192.168.136.135:6443 --token abcdef.0123456789abcdef \
    --discovery-token-ca-cert-hash sha256:1c4305f032f4bf534f628c32f5039084f4b103c922ff71b12a5f0f98d1ca9a4f

接下来按照上述提示信息操作,配置kubectl客户端的认证

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

⚠️注意:此时使用 kubectl get nodes查看节点应该处于notReady状态,因为还未配置网络插件

若执行初始化过程中出错,根据错误信息调整后,执行kubeadm reset后再次执行init操作即可

5. 添加slave节点到集群中

操作节点:所有的slave节点(k8s-slave)需要执行 在每台slave节点,执行如下命令,该命令是在kubeadm init成功后提示信息中打印出来的,需要替换成实际init后打印出的命令。

kubeadm join 192.168.136.135:6443 --token abcdef.0123456789abcdef \
    --discovery-token-ca-cert-hash sha256:1c4305f032f4bf534f628c32f5039084f4b103c922ff71b12a5f0f98d1ca9a4f

6. 安装flannel插件

操作节点:只在master节点(k8s-master)执行

  • 下载flannel的yaml文件
wget https://raw.githubusercontent.com/coreos/flannel/2140ac876ef134e0ed5af15c65e414cf26827915/Documentation/kube-flannel.yml
  • 修改配置,指定网卡名称,大概在文件的190行,添加一行配置:
$ vi kube-flannel.yml
...      
      containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.11.0-amd64
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        - --iface=eth0  # 如果机器存在多网卡的话,指定内网网卡的名称,默认不指定的话会找第一块网
        resources:
          requests:
            cpu: "100m"
...
  • 执行安装flannel网络插件
# 先拉取镜像,此过程国内速度比较慢
$ docker pull quay.io/coreos/flannel:v0.11.0-amd64
# 执行flannel安装
$ kubectl create -f kube-flannel.yml

7. 设置master节点为可调度

操作节点:k8s-master

默认部署成功后,master节点无法调度业务pod,如需设置master节点也可以参与pod的调度,需执行:

$ kubectl taint node k8s-master node-role.kubernetes.io/master:NoSchedule-

8. 验证集群

操作节点: 在master节点(k8s-master)执行

$ kubectl get nodes  #观察集群节点是否全部Ready

创建测试nginx服务

$ kubectl run  test-nginx --image=nginx:alpine

查看pod是否创建成功,并访问pod ip测试是否可用

$ kubectl get po -o wide
NAME                          READY   STATUS    RESTARTS   AGE   IP           NODE         NOMINATED NODE   READINESS GATES
test-nginx-5bd8859b98-5nnnw   1/1     Running   0          9s    10.244.1.2   k8s-slave1   <none>           <none>
$ curl 10.244.1.2
...
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

10. 清理环境

如果你的集群安装过程中遇到了其他问题,我们可以使用下面的命令来进行重置:

$ kubeadm reset
$ ifconfig cni0 down && ip link delete cni0
$ ifconfig flannel.1 down && ip link delete flannel.1
$ rm -rf /var/lib/cni/

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