一，前言

前两篇，购买了 3 台阿里云服务器并完成了 ci-server 构建服务器的环境安装与配置；

三台服务器规划如下：

服务配置内网IP外网IP说明
ci-server2c4g172.17.178.104182.92.4.158Jenkins + Nexus + Docker
k8s-master2c4g172.17.178.10547.93.9.45Kubernetes + Docker
k8s-node2c1g172.17.178.10639.105.58.35Kubernetes + Docker

本篇，配置 k8s-master 和 k8s-node 两台服务器，搭建 k8s 集群；

备注：考虑服务器成本使用 1 主+1 从的集群配置，有条件也可以使用 1 主 + 2 从；

二，Kubernetes 简介

1，k8s 简介

  • kubernetes 简称 K8s，其中数字 8 指代中间的 8 个字符 ubernete；
  • K8s 是一个开源的，用于管理云平台上多个主机上的容器化的应用；
  • K8s 的目标是让部署容器化的应用简单并且高效；
  • K8s 提供了应用部署，规划，更新，维护的一种机制；
  • K8s 是一个部署镜像的平台，可以用来调度多台机器上的的镜像部署操作；

K8s 可以使用集群来组织服务器，集群中存在 1 个 Master 集群控制节点，负责调度集群中其他服务器的资源；除 master 之外的其他节点称为 Node；

2，为什么要使用 k8s

大型互联网公司（如 Google），拥有上亿级别的 docker 容器，

容器维护涉及启动、停止、销毁、负载均衡、灾备、扩容等诸多问题需要解决，

因此传统的手工部署的方式就不切实际了，需要使用容器编排工具，而 k8s 目前是这个领域事实上的标准；

部署一个网站会涉及多个容器，可以通过 k8s 配置容器的部署、启动、关闭以及实现负载均衡；

三，k8s 集群搭建

以下配置，如未做特殊说明，则 k8s-master 和 k8s-node 默认都需要进行配置；

1，关闭 Swap 交换分区

swap 分区：虚拟内存分区；

Swap 分区：是 Linux 的交换分区，当系统资源不足时，Swap 分区将会启用；

比如，1c1g 配置的服务器，当需要 2g 内存时，便会从硬盘借用空间当做内存使用（但速度会比内存慢)；

搭建 k8s 集群：1 个 master + n 个 node；

当 master 资源不足时，新任务将自动调度到集群中的其他 node 节点处理，实现负载均衡，所以无需启用虚拟内存分区；

#关闭swap分区
swapoff -a

备注：k8s 虽然是一个集群架构，但单从表现上看和一台服务器是一样的：内存资源可以互相共享；

2，关闭 Selinux

  • 关闭 Selinux：达到支持容器访问宿主机的文件系统；
# 暂时关闭 selinux
setenforce 0

# 永久关闭
vi /etc/sysconfig/selinux
# 修改以下参数，设置为disable
SELINUX=disabled

Linux 部分权限比较严格，不方便操作

[root@k8s-master ~]# setenforce 0
setenforce: SELinux is disabled

3，统一系统时间和时区

使用 ntpdate 统一系统的时间和时区，服务器时间与阿里云服务器保持一致；

# 统一时区，为上海时区
ln -snf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
bash -c "echo 'Asia/Shanghai' > /etc/timezone"

# 统一使用阿里服务器进行时间更新
ntpdate ntp1.aliyun.com

实际操作：

// ln：软连接，创建软连接，从 /usr/share/zoneinfo/Asia/Shanghai 到 /etc/localtime
[root@k8s-master ~]# ln -snf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

// bash -c：执行 shell 脚本，将 Asia/Shanghai 写入到 /etc/timezone 中，使用亚洲/上海时区
[root@k8s-master ~]# bash -c "echo 'Asia/Shanghai' > /etc/timezone"

// 让服务器时间与阿里云标准时间对齐
[root@k8s-master ~]# ntpdate ntp1.aliyun.com
20 Dec 16:03:31 ntpdate[1608]: adjust time server 120.25.115.20 offset -0.003746 sec

备注：需要确保服务器之间的时间和时区一致，以避免执行定时任务时产生误差；

4，安装 Docker

在 kubernetes 中，组件、服务均能够以 Docker 镜像的方式进行部署，需要 docker 环境支持；

// 安装 docker 依赖的基础库
yum install -y yum-utils device-mapper-persistent-data lvm2

device-mapper-persistent-data：存储驱动，Linux 上的许多高级卷管理技术；

lvm：逻辑卷管理器，用于创建逻辑磁盘分区使用；

在安装 docker 前，需要先配置 docker 安装源：

// 添加阿里云的 docker 安装源
[root@k8s-node ~]# sudo yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
已加载插件：fastestmirror
adding repo from: http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
grabbing file http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo to /etc/yum.repos.d/docker-ce.repo
repo saved to /etc/yum.repos.d/docker-ce.repo

安装 docker-ce：

yum install docker-ce -y

启动 docker 并设置为开机启动：

// 启动 docker
[root@k8s-master yum.repos.d]# systemctl start docker
// 设置开机启动
[root@k8s-master yum.repos.d]# systemctl enable docker
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.

设置安装镜像源，使用阿里云镜像源：

// 创建配置目录
sudo mkdir -p /etc/docker
// 创建文件 daemon.json
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://fwvjnv59.mirror.aliyuncs.com"]
}
EOF

实际操作：

[root@k8s-master yum.repos.d]# sudo mkdir -p /etc/docker
[root@k8s-master yum.repos.d]# sudo tee /etc/docker/daemon.json <<-'EOF'
> {
>   "registry-mirrors": ["https://fwvjnv59.mirror.aliyuncs.com"]
> }
> EOF
{
  "registry-mirrors": ["https://fwvjnv59.mirror.aliyuncs.com"]
}

重启 docker，完成配置文件的重新加载：

sudo systemctl daemon-reload
sudo systemctl restart docker.service

这样，docker 获取镜像时就会通过阿里云镜像仓库拉取，速度会快一些；

5，安装 Kubernetes 组件

1，切换 k8s 下载源

\

指定 yum 安装 k8s 的下载地址为“阿里云”源：

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[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
2，安装 Kubernetes 核心组件

k8s 的三个核心组件：

  • kubelet：Kubernetes 核心组件。运行在集群所有节点上，负责创建、启动服务容器；
  • kubectl：Kubernetes 的命令行工具。可以用来管理，删除，创建资源；
  • kubeadm：用来初始化集群，子节点加入的工具；
// 安装最新版本，会导致安装问题
yum install -y kubelet kubectl kubeadm

// 建议指定版本安装
yum install -y kubelet-1.20.4 kubectl-1.20.4 kubeadm-1.20.4

注意：在不指定组件版本的情况下，默认会安装最新版本（此时最新版本为 1.23.1）

这样可能导致 k8s 初始化报错：

执行：

kubeadm init --config init-kubeadm.conf

报错：

[kubelet-check] It seems like the kubelet isn’t running or healthy.

[kubelet-check] The HTTP call equal to 'curl -sSL http://localhost:10248/healthz’ failed with error: Get "http://localhost:10248/healthz": dial tcp [::1]:10248: connect: connection refused.

解决办法：

网上的解决办法均未实现，指定 1.20.4 版本安装无此问题，建议使用 1.20.4 版本；

3，kubeadm 介绍

k8s 与 mysql 组件功能对照

mysql组件组件功能对标 K8s 组件组件功能
mysqldmysql 的后台服务器；kubeletk8s 的后台运行程序；
mysqlmysql 的客户端，作为命令行工具向 mysql 服务器发送指令；kubectlk8s 的客户端，作为命令行工具向 kubelet 服务器发送指令，用于管理、创建、删除 k8s 资源；
mysqladminmysql 的管理员工具，如：重启、关闭服务器；kubeadmk8s 的管理员工具，用于初始化集群、提供配置文件等；
4，启动 kubelet
# 启动 kubelet 并配置为开机启动
[root@k8s-master ~]# systemctl enable kubelet && systemctl start kubelet
Created symlink from /etc/systemd/system/multi-user.target.wants/kubelet.service to /usr/lib/systemd/system/kubelet.service.
5，设置 bridge-nf-call-iptables

开启 bridge-nf-call-iptables，配置内核参数，将桥接的 IPV4 浏览传递到 iptables 链

echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables
6，配置 Master 服务器（修改主机名：k8s-master）

Master 节点：负责集群中的任务调度；

hostnamectl set-hostname k8s-master

查看 hosts 文件

[root@k8s-master ~]# cat /etc/hosts
::1	localhost	localhost.localdomain	localhost6	localhost6.localdomain6
127.0.0.1	localhost	localhost.localdomain	localhost4	localhost4.localdomain4

172.17.178.105	k8s-master	k8s-master
7，配置 Node 服务器（修改主机名：k8s-node）

Node 节点：负责接收调度，运行服务容器；

hostnamectl set-hostname k8s-node

查看 hosts 文件:

[root@k8s-node ~]# cat /etc/hosts
cat /etc/hosts
::1	localhost	localhost.localdomain	localhost6	localhost6.localdomain6
127.0.0.1	localhost	localhost.localdomain	localhost4	localhost4.localdomain4

172.17.178.106	k8s-node	k8s-node
8，配置 Master（hosts 添加 k8s-node）

在 k8s-master 中，添加 k8s-node：

[root@k8s-master ~]# vi /etc/hosts

::1     localhost       localhost.localdomain   localhost6      localhost6.localdomain6
127.0.0.1       localhost       localhost.localdomain   localhost4      localhost4.localdomain4

172.17.178.105  k8s-master
172.17.178.106  k8s-node

在 k8s-master 执行 ping k8s-node，测试主从通信：

[root@k8s-master ~]# ping k8s-node
PING k8s-node (172.17.178.106) 56(84) bytes of data.
64 bytes from k8s-node (172.17.178.106): icmp_seq=1 ttl=64 time=0.492 ms
64 bytes from k8s-node (172.17.178.106): icmp_seq=2 ttl=64 time=0.307 ms
64 bytes from k8s-node (172.17.178.106): icmp_seq=3 ttl=64 time=0.299 ms
64 bytes from k8s-node (172.17.178.106): icmp_seq=4 ttl=64 time=0.296 ms
64 bytes from k8s-node (172.17.178.106): icmp_seq=5 ttl=64 time=0.328 ms
^C
--- k8s-node ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4000ms
rtt min/avg/max/mdev = 0.296/0.344/0.492/0.076 ms
9，配置 Node（hosts 添加 k8s-master）

在 k8s-node 中，添加 k8s-master：

[root@k8s-node ~]# vi /etc/hosts

::1     localhost       localhost.localdomain   localhost6      localhost6.localdomain6
127.0.0.1       localhost       localhost.localdomain   localhost4      localhost4.localdomain4

172.17.178.106  k8s-node        
172.17.178.105  k8s-master

在 k8s-node 中执行 ping k8s-master ，测试主从通信：

[root@k8s-node ~]# ping k8s-master
PING k8s-master (172.17.178.105) 56(84) bytes of data.
64 bytes from k8s-master (172.17.178.105): icmp_seq=1 ttl=64 time=0.361 ms
64 bytes from k8s-master (172.17.178.105): icmp_seq=2 ttl=64 time=1.01 ms
64 bytes from k8s-master (172.17.178.105): icmp_seq=3 ttl=64 time=0.314 ms
^C
--- k8s-master ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2013ms
rtt min/avg/max/mdev = 0.314/0.564/1.018/0.321 ms

完成测试，目前主从两台服务器可以相互 ping 通

10，生成 Kubernetes 初始化文件（仅 master 操作即可）

init-defaults：输出一份默认初始化配置文件；

// 执行 init-defaults 命令，并将输出结果写入 init-kubeadm.conf 中
[root@k8s-master ~]# kubeadm config print init-defaults > init-kubeadm.conf

// 修改配置：镜像仓库
[root@k8s-master ~]# cat init-kubeadm.conf
apiVersion: kubeadm.k8s.io/v1beta3
bootstrapTokens:
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: abcdef.0123456789abcdef
  ttl: 24h0m0s
  usages:
  - signing
  - authentication
kind: InitConfiguration
localAPIEndpoint:
  advertiseAddress: 1.2.3.4
  bindPort: 6443
nodeRegistration:
  criSocket: /var/run/dockershim.sock
  imagePullPolicy: IfNotPresent
  name: node
  taints: null
---
apiServer:
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta3
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns: {}
etcd:
  local:
    dataDir: /var/lib/etcd
imageRepository: k8s.gcr.io
kind: ClusterConfiguration
kubernetesVersion: 1.23.0
networking:
  dnsDomain: cluster.local
  serviceSubnet: 10.96.0.0/12
scheduler: {}
11，修改 init-kubeadm.conf 配置项

需要修改以下三处配置

1，配置 k8s 拉取 docker 镜像的地址为阿里云镜像源；

2，本地 api 端点：广播地址，需修改为 k8s-master 的 ip；

3，添加 network 中的 pod 子网配置；

// 镜像仓库地址
imageRepository: k8s.gcr.io 
imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers // 更换 k8s 镜像仓库

// 本地 api 端点
localAPIEndpoint:
  advertiseAddress: 1.2.3.4   
  bindPort: 6443

localAPIEndpoint:
  advertiseAddress: 172.17.178.105    // 广播地址，需修改为 k8s-master 的 ip
  bindPort: 6443

// 添加 network
networking:
  dnsDomain: cluster.local
  serviceSubnet: 10.96.0.0/12

networking:
  dnsDomain: cluster.local		  // dns 域名
  serviceSubnet: 10.96.0.0/12   // 服务子网
	podSubnet: 10.244.0.0/16			// pod 子网配置

了解 podSubnet 需要先了解 k8s 架构，详见附：k8s 架构；

12，查看并拉取缺少的组件

配置文件中的镜像列表：目前已经安装了 k8s 的 3 个核心组件，还差 7 个组件

// 查看缺少的组件（缺少以下 7 个组件）
[root@k8s-master ~]# kubeadm config images list --config init-kubeadm.conf
registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.20.0
registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.20.0
registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.20.0
registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.20.0
registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.2
registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.4.13-0
registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:1.7.0

// 拉取缺少的 7 个组件
[root@k8s-master ~]# kubeadm config images pull --config init-kubeadm.conf
[config/images] Pulled registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.20.0
[config/images] Pulled registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.20.0
[config/images] Pulled registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.20.0
[config/images] Pulled registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.20.0
[config/images] Pulled registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.2
[config/images] Pulled registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.4.13-0
[config/images] Pulled registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:1.7.0

6，初始化 Kubernetes

1，通过 init-kubeadm.conf 初始化 k8s
  • kubeadm join 可以快速将 Node 节点加入到 Master 集群内
  • 将默认的 Kubernetes 认证文件拷贝到 .kube 文件夹内，默认使用该配置文件

在 Master 节点执行 k8s 集群初始化命令：

// 通过 init-kubeadm.conf 初始化 k8s
[root@k8s-master ~]# kubeadm init --config init-kubeadm.conf
[init] Using Kubernetes version: v1.20.0
[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: 20.10.12. 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"
[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 [10.96.0.1 172.17.178.105]
[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 [172.17.178.105 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-master localhost] and IPs [172.17.178.105 127.0.0.1 ::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"
[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"
[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"
[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
[kubelet-check] Initial timeout of 40s passed.
[apiclient] All control plane components are healthy after 64.005020 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.20" 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 labels "node-role.kubernetes.io/master=''" and "node-role.kubernetes.io/control-plane='' (deprecated)"
[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: abcdef.0123456789abcdef
[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

Alternatively, if you are the root user, you can run:

  export KUBECONFIG=/etc/kubernetes/admin.conf

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 172.17.178.105:6443 --token abcdef.0123456789abcdef \
    --discovery-token-ca-cert-hash sha256:31e43ceaaf17f2c0d738ba6efa7fa71c6b5ad0d818a900a10b3e76bc397b5f7a

安装完成后的提示，注意以下两部分：

// 1，创建目录、添加配置、修改权限
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

// 2，在 node 节点执行以下命令，加入到 k8s 集群汇中：
Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 172.17.178.105:6443 --token abcdef.0123456789abcdef \
    --discovery-token-ca-cert-hash sha256:31e43ceaaf17f2c0d738ba6efa7fa71c6b5ad0d818a900a10b3e76bc397b5f7a
2，创建配置文件

根据安装完成后的提示，创建目录、拷贝 k8s 配置、修改权限

[root@k8s-master ~]# mkdir -p $HOME/.kube
[root@k8s-master ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@k8s-master ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config
3，查看节点启动情况
[root@k8s-master ~]# kubectl get nodes
NAME         STATUS     ROLES                  AGE   VERSION
k8s-master   NotReady   control-plane,master   15m   v1.20.4

可以发现，k8s-master 节点，目前还是 NotReady 状态；

7，安装 Flannel

flannel 主要的作用是通过创建一个虚拟网络，让不同节点下的服务具有全局唯一的 IP 地址，且服务之见可以互相访问和连接；集群内网网络通信协议通信模式采用了 Flannel 协议；

1，安装 Flannel 内网通讯协议
// 下载 kube-flannel.yml
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

// 拉取镜像
docker pull quay.io/coreos/flannel:v0.13.0-rc2

备注：raw.githubusercontent.com被墙可以网上下载文件内容

查看 kube-flannel.yml 内容

[root@k8s-master ~]# cat kube-flannel.yml
---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
  name: psp.flannel.unprivileged
  annotations:
    seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
    seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
    apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
    apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
  privileged: false
  volumes:
  - configMap
  - secret
  - emptyDir
  - hostPath
  allowedHostPaths:
  - pathPrefix: "/etc/cni/net.d"
  - pathPrefix: "/etc/kube-flannel"
  - pathPrefix: "/run/flannel"
  readOnlyRootFilesystem: false
  # Users and groups
  runAsUser:
    rule: RunAsAny
  supplementalGroups:
    rule: RunAsAny
  fsGroup:
    rule: RunAsAny
  # Privilege Escalation
  allowPrivilegeEscalation: false
  defaultAllowPrivilegeEscalation: false
  # Capabilities
  allowedCapabilities: ['NET_ADMIN', 'NET_RAW']
  defaultAddCapabilities: []
  requiredDropCapabilities: []
  # Host namespaces
  hostPID: false
  hostIPC: false
  hostNetwork: true
  hostPorts:
  - min: 0
    max: 65535
  # SELinux
  seLinux:
    # SELinux is unused in CaaSP
    rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: flannel
rules:
- apiGroups: ['extensions']
  resources: ['podsecuritypolicies']
  verbs: ['use']
  resourceNames: ['psp.flannel.unprivileged']
- apiGroups:
  - ""
  resources:
  - pods
  verbs:
  - get
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - nodes/status
  verbs:
  - patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: flannel
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: flannel
subjects:
- kind: ServiceAccount
  name: flannel
  namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: flannel
  namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
  name: kube-flannel-cfg
  namespace: kube-system
  labels:
    tier: node
    app: flannel
data:
  cni-conf.json: |
    {
      "name": "cbr0",
      "cniVersion": "0.3.1",
      "plugins": [
        {
          "type": "flannel",
          "delegate": {
            "hairpinMode": true,
            "isDefaultGateway": true
          }
        },
        {
          "type": "portmap",
          "capabilities": {
            "portMappings": true
          }
        }
      ]
    }
  net-conf.json: |
    {
      "Network": "10.244.0.0/16",
      "Backend": {
        "Type": "vxlan"
      }
    }
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: kube-flannel-ds
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  selector:
    matchLabels:
      app: flannel
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: kubernetes.io/os
                operator: In
                values:
                - linux
      hostNetwork: true
      priorityClassName: system-node-critical
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.13.1-rc2
        command:
        - cp
        args:
        - -f
        - /etc/kube-flannel/cni-conf.json
        - /etc/cni/net.d/10-flannel.conflist
        volumeMounts:
        - name: cni
          mountPath: /etc/cni/net.d
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.13.1-rc2
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: false
          capabilities:
            add: ["NET_ADMIN", "NET_RAW"]
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
      - name: run
        hostPath:
          path: /run/flannel
      - name: cni
        hostPath:
          path: /etc/cni/net.d
      - name: flannel-cfg
        configMap:
          name: kube-flannel-cfg

注意以下两个部分：

// 1,
image: quay.io/coreos/flannel:v0.13.1-rc2

// 2,
net-conf.json: |
{
  // 初始化时配置的 Pod 子网，三个 pod 互相通信，依靠 Flannel 协议组成子网
  "Network": "10.244.0.0/16",
  "Backend": {
    "Type": "vxlan"
  }
}
2，启动 Flannel
// 启动
kubectl apply -f kube-flannel.yml

// 实际执行
[root@k8s-master ~]# kubectl apply -f kube-flannel.yml
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created
3，查看节点启动情况
[root@k8s-master ~]# kubectl get nodes
NAME         STATUS   ROLES                  AGE   VERSION
k8s-master   Ready    control-plane,master   13h   v1.20.4

可以发现，k8s-master节点，目前已经是 Ready 状态；

8， node 节点配置

1，拷贝 Master 节点配置文件到 node

将 k8s-master 节点的配置文件拷贝到 k8s-node 节点

// 将当前 $HOME/.kube/config 文件，拷贝到指定 IP 的 HOME 中
[root@k8s-master ~]# scp $HOME/.kube/config root@172.17.178.106:~/ 
The authenticity of host '172.17.178.106 (172.17.178.106)' can't be established.
ECDSA key fingerprint is SHA256:59P14/vci6LQz7+cksAjPYi5IuYnC6FxaCPVBe+I2p8.
ECDSA key fingerprint is MD5:8e:bd:91:34:fa:c2:34:69:07:ae:33:cf:9a:7d:6d:c3.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '172.17.178.106' (ECDSA) to the list of known hosts.
root@172.17.178.106's password: 
config                                             100% 5566     8.5MB/s   00:00

到 k8s-node 上，查看拷贝结果：

[root@k8s-node ~]# ls
config kube-flannel.yml

在 k8s-node 节点上，归档配置文件

// 创建目录 $HOME/.kube 
[root@k8s-node ~]# mkdir -p $HOME/.kube 
// 将拷贝的 config 移动到 $HOME/.kube 中
[root@k8s-node ~]# sudo mv $HOME/config $HOME/.kube/config 
// 修改权限
[root@k8s-node ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config
2，将 node 节点加入到集群

根据安装完成后的提示，在 node 节点中执行命令，

// 让 k8s-node 节点加入到 k8s-master 集群内
[root@k8s-node ~]# kubeadm join 172.17.178.105:6443 --token abcdef.0123456789abcdef \
>     --discovery-token-ca-cert-hash sha256:31e43ceaaf17f2c0d738ba6efa7fa71c6b5ad0d818a900a10b3e76bc397b5f7a 
[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: 20.10.12. 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 -o yaml'
[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.

备注：当前的 node 节点，在前面已经完成了 3 个 k8s 核心组件的安装；

如果加入集群的命令丢失了，可以在 master 上使用 kubeadm token create 重新生成一条命令：

kubeadm token create --print-join-command
3，查看节点启动情况
[root@k8s-master ~]# kubectl get nodes
NAME         STATUS   ROLES                  AGE   VERSION
k8s-master   Ready    control-plane,master   13h   v1.20.4
k8s-node     Ready    <none>                 12h   v1.20.4

两个节点均已 Ready，k8s 集群配置完成；

四，结尾

本篇，完成了 k8s 两台服务器 k8s-master、k8s-node 的安装与配置；

下一篇，k8s 部署：直接部署和 yaml 部署

# kubernetes # docker # 运维
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