centos7使用kubeadm安装kubernetes 1.11版本多主高可用

[TOC]

kubernetes介绍
要学习一个新的东西，先了解它是什么，熟悉基本概念会有很大帮助。以下是我学习时看过的一篇核心概念介绍。
http://dockone.io/article/932

搭建Kubernetes集群环境有以下3种方式：

minikube
Minikube是一个工具，可以在本地快速运行一个单点的Kubernetes，尝试Kubernetes或日常开发的用户使用。不能用于生产环境。
官方地址：https://kubernetes.io/docs/setup/minikube/

以下是符合企业生产环境标准的Kubernetes集群环境方式：

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

官方地址：https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm/

二进制包
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。
官方也提供了一个互动测试环境供大家玩耍：https://kubernetes.io/cn/docs/tutorials/kubernetes-basics/cluster-interactive/

1. 实验环境说明

lab1: etcd master haproxy keepalived 192.168.105.92
lab2: etcd master haproxy keepalived 192.168.105.93
lab3: etcd master haproxy keepalived 192.168.105.94
lab4: node  192.168.105.95
lab4: node  192.168.105.96

vip(loadblancer ip): 192.168.105.99

virtualbox实验使用的Vagrantfile：

# -*- mode: ruby -*-
# vi: set ft=ruby :

ENV["LC_ALL"] = "en_US.UTF-8"

Vagrant.configure("2") do |config|
    (2..6).each do |i|
      config.vm.define "lab#{i}" do |node|
        node.vm.box = "centos-7.4-docker-17"
        node.ssh.insert_key = false
        node.vm.hostname = "lab#{i}"
        node.vm.network "private_network", ip: "192.168.105.9#{i}"
        node.vm.provision "shell",
          inline: "echo hello from node #{i}"
        node.vm.provider "virtualbox" do |v|
          v.cpus = 2
          v.customize ["modifyvm", :id, "--name", "lab#{i}", "--memory", "2048"]
        end
      end
    end
end

2. 准备yum源

使用阿里yum源，并将默认yum源文件都移走。

cd /etc/yum.repos.d
mkdir bak
mv *.repo bak/

vim CentOS-Base.repo

# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#

[base]
name=CentOS-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/os/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

#released updates
[updates]
name=CentOS-$releasever - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/updates/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/contrib/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/contrib/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

vim epel-7.repo

[epel]
name=Extra Packages for Enterprise Linux 7 - $basearch
baseurl=http://mirrors.aliyun.com/epel/7/$basearch
failovermethod=priority
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7

[epel-debuginfo]
name=Extra Packages for Enterprise Linux 7 - $basearch - Debug
baseurl=http://mirrors.aliyun.com/epel/7/$basearch/debug
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
gpgcheck=0

[epel-source]
name=Extra Packages for Enterprise Linux 7 - $basearch - Source
baseurl=http://mirrors.aliyun.com/epel/7/SRPMS
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
gpgcheck=0

vim docker-ce.repo

[docker-ce-stable]
name=Docker CE Stable - $basearch
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/$basearch/stable
enabled=1
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-stable-debuginfo]
name=Docker CE Stable - Debuginfo $basearch
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/debug-$basearch/stable
enabled=0
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-stable-source]
name=Docker CE Stable - Sources
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/source/stable
enabled=0
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-edge]
name=Docker CE Edge - $basearch
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/$basearch/edge
enabled=1
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-edge-debuginfo]
name=Docker CE Edge - Debuginfo $basearch
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/debug-$basearch/edge
enabled=0
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-edge-source]
name=Docker CE Edge - Sources
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/source/edge
enabled=0
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-test]
name=Docker CE Test - $basearch
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/$basearch/test
enabled=0
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-test-debuginfo]
name=Docker CE Test - Debuginfo $basearch
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/debug-$basearch/test
enabled=0
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-test-source]
name=Docker CE Test - Sources
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/source/test
enabled=0
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-nightly]
name=Docker CE Nightly - $basearch
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/$basearch/nightly
enabled=0
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-nightly-debuginfo]
name=Docker CE Nightly - Debuginfo $basearch
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/debug-$basearch/nightly
enabled=0
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

[docker-ce-nightly-source]
name=Docker CE Nightly - Sources
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/source/nightly
enabled=0
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg

vim 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

2. 安装配置docker

v1.11.1版本推荐使用docker v17.03,v1.11,v1.12,v1.13, 也可以使用，再高版本的docker可能无法正常使用。

这里安装v1.13版本。

yum -y install docker
systemctl enable docker && systemctl restart docker

docker启动错误解决：

Error starting daemon: SELinux is not supported with the overlay2 graph driver on this kernel. Either boot into a newer kernel or disable selinux in docke...-enabled=false)

修改/etc/sysconfig/docker中的--selinux-enabled=false

3. 安装 kubeadm, kubelet 和 kubectl

如下操作在所有节点操作

yum install -y kubelet kubeadm kubectl ipvsadm
systemctl enable kubelet && systemctl start kubelet

4. 配置系统相关参数

如下操作在所有节点操作

# 设置时区
ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

# 临时禁用selinux
# 永久关闭 修改/etc/sysconfig/selinux文件设置
sed -i ‘s/SELINUX=.*/SELINUX=disabled/‘ /etc/sysconfig/selinux
setenforce 0  # 需要重启生效

# 开启forward
# Docker从1.13版本开始调整了默认的防火墙规则
# 禁用了iptables filter表中FOWARD链
# 这样会引起Kubernetes集群中跨Node的Pod无法通信
iptables -P FORWARD ACCEPT

# 临时关闭swap
# 永久关闭 注释/etc/fstab文件里swap相关的行
swapoff -a

# 开启防火墙允许集群机器间通信（为了方便测试或者直接关闭防火墙）
firewall-cmd --add-rich-rule ‘rule family=ipv4 source address=192.168.105.0/24 accept‘ # # 指定源IP（段），即时生效
firewall-cmd --add-rich-rule ‘rule family=ipv4 source address=192.168.105.0/24 accept‘ --permanent # 指定源IP（段），永久生效

如下操作在所有master节点操作

# 配置转发相关参数，否则可能会出错
cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
vm.swappiness=0
EOF
sysctl --system

# 加载ipvs相关内核模块
# 如果重新开机，需要重新加载
modprobe ip_vs
modprobe ip_vs_rr
modprobe ip_vs_wrr
modprobe ip_vs_sh
modprobe nf_conntrack_ipv4
lsmod | grep ip_vs

5. 配置hosts解析

如下操作在所有节点操作

cat >>/etc/hosts<<EOF
192.168.105.92 lab1
192.168.105.93 lab2
192.168.105.94 lab3
192.168.105.95 lab4
192.168.105.96 lab5
EOF

6. 配置haproxy代理和keepalived

如下操作在节点lab1,lab2,lab3操作

# 拉取haproxy镜像
docker pull haproxy:1.7.8-alpine
mkdir /etc/haproxy
cat >/etc/haproxy/haproxy.cfg<<EOF
global
  log 127.0.0.1 local0 err
  maxconn 50000
  uid 99
  gid 99
  #daemon
  nbproc 1
  pidfile haproxy.pid

defaults
  mode http
  log 127.0.0.1 local0 err
  maxconn 50000
  retries 3
  timeout connect 5s
  timeout client 30s
  timeout server 30s
  timeout check 2s

listen admin_stats
  mode http
  bind 0.0.0.0:1080
  log 127.0.0.1 local0 err
  stats refresh 30s
  stats uri     /haproxy-status
  stats realm   Haproxy\ Statistics
  stats auth    will:will
  stats hide-version
  stats admin if TRUE

frontend k8s-https
  bind 0.0.0.0:8443
  mode tcp
  #maxconn 50000
  default_backend k8s-https

backend k8s-https
  mode tcp
  balance roundrobin
  server lab1 192.168.105.92:6443 weight 1 maxconn 1000 check inter 2000 rise 2 fall 3
  server lab2 192.168.105.93:6443 weight 1 maxconn 1000 check inter 2000 rise 2 fall 3
  server lab3 192.168.105.94:6443 weight 1 maxconn 1000 check inter 2000 rise 2 fall 3
EOF

# 启动haproxy
docker run -d --name my-haproxy -v /etc/haproxy:/usr/local/etc/haproxy:ro -p 8443:8443 -p 1080:1080 --restart always haproxy:1.7.8-alpine

# 查看日志
docker logs my-haproxy

# 浏览器查看状态
http://192.168.105.92:1080/haproxy-status
http://192.168.105.93:1080/haproxy-status
http://192.168.105.94:1080/haproxy-status

# 拉取keepalived镜像
docker pull osixia/keepalived:1.4.4

# 启动
# 载入内核相关模块
lsmod | grep ip_vs
modprobe ip_vs

# 启动keepalived
# ens32为本次实验192.168.105.0/24网段的所在网卡
docker run --net=host --cap-add=NET_ADMIN -e KEEPALIVED_INTERFACE=ens32 -e KEEPALIVED_VIRTUAL_IPS="#PYTHON2BASH:[‘192.168.105.99‘]" -e KEEPALIVED_UNICAST_PEERS="#PYTHON2BASH:[‘192.168.105.92‘,‘192.168.105.93‘,‘192.168.105.94‘]" -e KEEPALIVED_PASSWORD=hello --name k8s-keepalived --restart always -d osixia/keepalived:1.4.4

# 查看日志
# 会看到两个成为backup 一个成为master
docker logs k8s-keepalived

# 此时会配置 192.168.105.99 到其中一台机器
# ping测试
ping -c4 192.168.105.99

# 如果失败后清理后，重新实验
#docker rm -f k8s-keepalived
#ip a del 192.168.105.99/32 dev ens32

7. 配置启动kubelet

如下操作在所有节点操作

# 配置kubelet使用国内pause镜像
# 配置kubelet的cgroups
# 获取docker的cgroups
DOCKER_CGROUPS=$(docker info | grep ‘Cgroup‘ | cut -d‘ ‘ -f3)
echo $DOCKER_CGROUPS
cat >/etc/sysconfig/kubelet<<EOF
KUBELET_EXTRA_ARGS="--cgroup-driver=$DOCKER_CGROUPS --pod-infra-container-image=registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64:3.1"
EOF

# 启动
systemctl daemon-reload
systemctl enable kubelet && systemctl restart kubelet

8. 配置master

8.1 配置第一个master

如下操作在lab1节点操作

# 1.11 版本 centos 下使用 ipvs 模式会出问题
# 参考 https://github.com/kubernetes/kubernetes/issues/65461

cd /etc/kubernetes
# 生成配置文件
CP0_IP="192.168.105.92"
CP0_HOSTNAME="lab1"
cat >kubeadm-master.config<<EOF
apiVersion: kubeadm.k8s.io/v1alpha2
kind: MasterConfiguration
kubernetesVersion: v1.11.1
imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers

apiServerCertSANs:
- "lab1"
- "lab2"
- "lab3"
- "192.168.105.92"
- "192.168.105.93"
- "192.168.105.94"
- "192.168.105.99"
- "127.0.0.1"

api:
  advertiseAddress: $CP0_IP
  controlPlaneEndpoint: 192.168.105.99:8443

etcd:
  local:
    extraArgs:
      listen-client-urls: "https://127.0.0.1:2379,https://$CP0_IP:2379"
      advertise-client-urls: "https://$CP0_IP:2379"
      listen-peer-urls: "https://$CP0_IP:2380"
      initial-advertise-peer-urls: "https://$CP0_IP:2380"
      initial-cluster: "$CP0_HOSTNAME=https://$CP0_IP:2380"
    serverCertSANs:
      - $CP0_HOSTNAME
      - $CP0_IP
    peerCertSANs:
      - $CP0_HOSTNAME
      - $CP0_IP

controllerManagerExtraArgs:
  node-monitor-grace-period: 10s
  pod-eviction-timeout: 10s

networking:
  podSubnet: 10.244.0.0/16

kubeProxy:
  config:
    # mode: ipvs
    mode: iptables
EOF

# 提前拉取镜像
# 如果执行失败 可以多次执行
kubeadm config images pull --config kubeadm-master.config

# 初始化
# 注意保存返回的 join 命令
kubeadm init --config kubeadm-master.config

# 初始化失败时使用
#kubeadm reset

# 将ca相关文件传至其他master节点
USER=root # customizable
CONTROL_PLANE_IPS="lab2 lab3"
for host in ${CONTROL_PLANE_IPS}; do
    scp /etc/kubernetes/pki/ca.crt "${USER}"@$host:/etc/kubernetes/pki/ca.crt
    scp /etc/kubernetes/pki/ca.key "${USER}"@$host:/etc/kubernetes/pki/ca.key
    scp /etc/kubernetes/pki/sa.key "${USER}"@$host:/etc/kubernetes/pki/sa.key
    scp /etc/kubernetes/pki/sa.pub "${USER}"@$host:/etc/kubernetes/pki/sa.pub
    scp /etc/kubernetes/pki/front-proxy-ca.crt "${USER}"@$host:/etc/kubernetes/pki/front-proxy-ca.crt
    scp /etc/kubernetes/pki/front-proxy-ca.key "${USER}"@$host:/etc/kubernetes/pki/front-proxy-ca.key
    ssh "${USER}"@$host "mkdir -p /etc/kubernetes/pki/etcd"
    scp /etc/kubernetes/pki/etcd/ca.crt "${USER}"@$host:/etc/kubernetes/pki/etcd/ca.crt
    scp /etc/kubernetes/pki/etcd/ca.key "${USER}"@$host:/etc/kubernetes/pki/etcd/ca.key
    scp /etc/kubernetes/admin.conf "${USER}"@$host:/etc/kubernetes/admin.conf
done

kubeadm init失败解决：
将阿里云image tag成官方的image，即可解决init失败问题。(v1.11.0有此问题)

docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver-amd64:v1.11.1 k8s.gcr.io/kube-apiserver-amd64:v1.11.1
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy-amd64:v1.11.1 k8s.gcr.io/kube-proxy-amd64:v1.11.1
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/etcd-amd64:3.2.18 k8s.gcr.io/etcd-amd64:3.2.18
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler-amd64:v1.11.1 k8s.gcr.io/kube-scheduler-amd64:v1.11.1
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager-amd64:v1.11.1 k8s.gcr.io/kube-controller-manager-amd64:v1.11.1
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:1.1.3 k8s.gcr.io/coredns:1.1.3
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64:3.1 k8s.gcr.io/pause-amd64:3.1
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1 k8s.gcr.io/pause:3.1

docker images # 结果如下

docker images
REPOSITORY                                                                          TAG                 IMAGE ID            CREATED             SIZE
k8s.gcr.io/kube-apiserver-amd64                                                     v1.11.1             214c48e87f58        3 weeks ago         187 MB
registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver-amd64            v1.11.1             214c48e87f58        3 weeks ago         187 MB
k8s.gcr.io/kube-proxy-amd64                                                         v1.11.1             1d3d7afd77d1        3 weeks ago         97.8 MB
registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy-amd64                v1.11.1             1d3d7afd77d1        3 weeks ago         97.8 MB
k8s.gcr.io/kube-controller-manager-amd64                                            v1.11.1             55b70b420785        3 weeks ago         155 MB
registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager-amd64   v1.11.1             55b70b420785        3 weeks ago         155 MB
k8s.gcr.io/kube-scheduler-amd64                                                     v1.11.1             0e4a34a3b0e6        3 weeks ago         56.8 MB
registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler-amd64            v1.11.1             0e4a34a3b0e6        3 weeks ago         56.8 MB
k8s.gcr.io/coredns                                                                  1.1.3               b3b94275d97c        2 months ago        45.6 MB
registry.cn-hangzhou.aliyuncs.com/google_containers/coredns                         1.1.3               b3b94275d97c        2 months ago        45.6 MB
docker.io/osixia/keepalived                                                         1.4.4               d83816204582        2 months ago        53.7 MB
registry.cn-shanghai.aliyuncs.com/gcr-k8s/flannel                                   v0.10.0-amd64       b949a39093d6        2 months ago        44.6 MB
k8s.gcr.io/etcd-amd64                                                               3.2.18              b8df3b177be2        3 months ago        219 MB
registry.cn-hangzhou.aliyuncs.com/google_containers/etcd-amd64                      3.2.18              b8df3b177be2        3 months ago        219 MB
quay.io/coreos/flannel                                                              v0.10.0-amd64       f0fad859c909        6 months ago        44.6 MB
k8s.gcr.io/pause-amd64                                                              3.1                 da86e6ba6ca1        7 months ago        742 kB
k8s.gcr.io/pause                                                                    3.1                 da86e6ba6ca1        7 months ago        742 kB
registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64                     3.1                 da86e6ba6ca1        7 months ago        742 kB
registry.cn-hangzhou.aliyuncs.com/google_containers/pause                           3.1                 da86e6ba6ca1        7 months ago        742 kB
docker.io/haproxy                                                                   1.7.8-alpine        297a495c0e70        12 months ago       14.7 MB

8.2 配置第二个master

如下操作在lab2节点操作

# 1.11 版本 centos 下使用 ipvs 模式会出问题
# 参考 https://github.com/kubernetes/kubernetes/issues/65461

cd /etc/kubernetes
# 生成配置文件
CP0_IP="192.168.105.92"
CP0_HOSTNAME="lab1"
CP1_IP="192.168.105.93"
CP1_HOSTNAME="lab2"
cat >kubeadm-master.config<<EOF
apiVersion: kubeadm.k8s.io/v1alpha2
kind: MasterConfiguration
kubernetesVersion: v1.11.1
imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers

apiServerCertSANs:
- "lab1"
- "lab2"
- "lab3"
- "192.168.105.92"
- "192.168.105.93"
- "192.168.105.94"
- "192.168.105.99"
- "127.0.0.1"

api:
  advertiseAddress: $CP1_IP
  controlPlaneEndpoint: 192.168.105.99:8443

etcd:
  local:
    extraArgs:
      listen-client-urls: "https://127.0.0.1:2379,https://$CP1_IP:2379"
      advertise-client-urls: "https://$CP1_IP:2379"
      listen-peer-urls: "https://$CP1_IP:2380"
      initial-advertise-peer-urls: "https://$CP1_IP:2380"
      initial-cluster: "$CP0_HOSTNAME=https://$CP0_IP:2380,$CP1_HOSTNAME=https://$CP1_IP:2380"
      initial-cluster-state: existing
    serverCertSANs:
      - $CP1_HOSTNAME
      - $CP1_IP
    peerCertSANs:
      - $CP1_HOSTNAME
      - $CP1_IP

controllerManagerExtraArgs:
  node-monitor-grace-period: 10s
  pod-eviction-timeout: 10s

networking:
  podSubnet: 10.244.0.0/16

kubeProxy:
  config:
    # mode: ipvs
    mode: iptables
EOF

# 配置kubelet
kubeadm alpha phase certs all --config kubeadm-master.config
kubeadm alpha phase kubelet config write-to-disk --config kubeadm-master.config
kubeadm alpha phase kubelet write-env-file --config kubeadm-master.config
kubeadm alpha phase kubeconfig kubelet --config kubeadm-master.config
systemctl restart kubelet

# 添加etcd到集群中
CP0_IP="192.168.105.92"
CP0_HOSTNAME="lab1"
CP1_IP="192.168.105.93"
CP1_HOSTNAME="lab2"
export KUBECONFIG=/etc/kubernetes/admin.conf
kubectl exec -n kube-system etcd-${CP0_HOSTNAME} -- etcdctl --ca-file /etc/kubernetes/pki/etcd/ca.crt --cert-file /etc/kubernetes/pki/etcd/peer.crt --key-file /etc/kubernetes/pki/etcd/peer.key --endpoints=https://${CP0_IP}:2379 member add ${CP1_HOSTNAME} https://${CP1_IP}:2380
kubeadm alpha phase etcd local --config kubeadm-master.config

# 提前拉取镜像
# 如果执行失败 可以多次执行
kubeadm config images pull --config kubeadm-master.config

# 部署
kubeadm alpha phase kubeconfig all --config kubeadm-master.config
kubeadm alpha phase controlplane all --config kubeadm-master.config
kubeadm alpha phase mark-master --config kubeadm-master.config

8.3 配置第三个master

如下操作在lab3节点操作

# 1.11 版本 centos 下使用 ipvs 模式会出问题
# 参考 https://github.com/kubernetes/kubernetes/issues/65461

cd /etc/kubernetes
# 生成配置文件
CP0_IP="192.168.105.92"
CP0_HOSTNAME="lab1"
CP1_IP="192.168.105.93"
CP1_HOSTNAME="lab2"
CP2_IP="192.168.105.94"
CP2_HOSTNAME="lab3"
cat >kubeadm-master.config<<EOF
apiVersion: kubeadm.k8s.io/v1alpha2
kind: MasterConfiguration
kubernetesVersion: v1.11.1
imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers

apiServerCertSANs:
- "lab1"
- "lab2"
- "lab3"
- "192.168.105.92"
- "192.168.105.93"
- "192.168.105.94"
- "192.168.105.99"
- "127.0.0.1"

api:
  advertiseAddress: $CP2_IP
  controlPlaneEndpoint: 192.168.105.99:8443

etcd:
  local:
    extraArgs:
      listen-client-urls: "https://127.0.0.1:2379,https://$CP2_IP:2379"
      advertise-client-urls: "https://$CP2_IP:2379"
      listen-peer-urls: "https://$CP2_IP:2380"
      initial-advertise-peer-urls: "https://$CP2_IP:2380"
      initial-cluster: "$CP0_HOSTNAME=https://$CP0_IP:2380,$CP1_HOSTNAME=https://$CP1_IP:2380,$CP2_HOSTNAME=https://$CP2_IP:2380"
      initial-cluster-state: existing
    serverCertSANs:
      - $CP2_HOSTNAME
      - $CP2_IP
    peerCertSANs:
      - $CP2_HOSTNAME
      - $CP2_IP

controllerManagerExtraArgs:
  node-monitor-grace-period: 10s
  pod-eviction-timeout: 10s

networking:
  podSubnet: 10.244.0.0/16

kubeProxy:
  config:
    # mode: ipvs
    mode: iptables
EOF

# 配置kubelet
kubeadm alpha phase certs all --config kubeadm-master.config
kubeadm alpha phase kubelet config write-to-disk --config kubeadm-master.config
kubeadm alpha phase kubelet write-env-file --config kubeadm-master.config
kubeadm alpha phase kubeconfig kubelet --config kubeadm-master.config
systemctl restart kubelet

# 添加etcd到集群中
CP0_IP="192.168.105.92"
CP0_HOSTNAME="lab1"
CP2_IP="192.168.105.94"
CP2_HOSTNAME="lab3"
KUBECONFIG=/etc/kubernetes/admin.conf
kubectl exec -n kube-system etcd-${CP0_HOSTNAME} -- etcdctl --ca-file /etc/kubernetes/pki/etcd/ca.crt --cert-file /etc/kubernetes/pki/etcd/peer.crt --key-file /etc/kubernetes/pki/etcd/peer.key --endpoints=https://${CP0_IP}:2379 member add ${CP2_HOSTNAME} https://${CP2_IP}:2380
kubeadm alpha phase etcd local --config kubeadm-master.config

# 提前拉取镜像
# 如果执行失败 可以多次执行
kubeadm config images pull --config kubeadm-master.config

# 部署
kubeadm alpha phase kubeconfig all --config kubeadm-master.config
kubeadm alpha phase controlplane all --config kubeadm-master.config
kubeadm alpha phase mark-master --config kubeadm-master.config

9. 配置使用kubectl

如下操作在任意master节点操作

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

# 查看node节点
kubectl get nodes

# 只有网络插件也安装配置完成之后，才能会显示为ready状态
# 设置master允许部署应用pod，参与工作负载，现在可以部署其他系统组件
# 如 dashboard, heapster, efk等
kubectl taint nodes --all node-role.kubernetes.io/master-

10. 配置使用网络插件

如下操作在任意master节点操作

# 下载配置
cd /etc/kubernetes
mkdir flannel && cd flannel
wget https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml

# 修改配置
# 此处的ip配置要与上面kubeadm的pod-network一致
  net-conf.json: |
    {
      "Network": "10.244.0.0/16",
      "Backend": {
        "Type": "vxlan"
      }
    }

# 修改镜像
image: registry.cn-shanghai.aliyuncs.com/gcr-k8s/flannel:v0.10.0-amd64

# 如果Node有多个网卡的话，参考flannel issues 39701，
# https://github.com/kubernetes/kubernetes/issues/39701
# 目前需要在kube-flannel.yml中使用--iface参数指定集群主机内网网卡的名称，
# 否则可能会出现dns无法解析。容器无法通信的情况，需要将kube-flannel.yml下载到本地，
# flanneld启动参数加上--iface=<iface-name>
    containers:
      - name: kube-flannel
        image: registry.cn-shanghai.aliyuncs.com/gcr-k8s/flannel:v0.10.0-amd64
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        - --iface=ens32

# 启动
kubectl apply -f kube-flannel.yml

# 查看
kubectl get pods --namespace kube-system
kubectl get svc --namespace kube-system

11. 配置node节点加入集群

如下操作在所有node节点操作

# 此命令为初始化master成功后返回的结果
kubeadm join 192.168.105.99:8443 --token j6zjtl.tgptijigkhhnuc23 --discovery-token-ca-cert-hash sha256:f3e9ae0841084185649b6c111b7e992465b81f2442d42871c6a15731a17dabba

node节点报错处理办法：

tail -f /var/log/message

Jul 26 07:52:21 localhost kubelet: E0726 07:52:21.336281   10018 summary.go:102] Failed to get system container stats for "/system.slice/kubelet.service": failed to get cgroup stats for "/system.slice/kubelet.service": failed to get container info for "/system.slice/kubelet.service": unknown container "/system.slice/kubelet.service"

在kubelet配置文件追加以下配置
/etc/sysconfig/kubelet

# Append configuration in Kubelet
--runtime-cgroups=/systemd/system.slice --kubelet-cgroups=/systemd/system.slice

12. 配置dashboard

默认是没web界面的，可以在master机器上安装一个dashboard插件，实现通过web来管理。

12.1 安装Dashboard插件

如下操作在任意master节点操作

cd /etc/kubernetes
wget https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/recommended/kubernetes-dashboard.yaml  # 下载

编辑kubernetes-dashboard.yaml文件`：

      - name: kubernetes-dashboard
        image: registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.8.3

执行命令

# 安装Dashboard插件
kubectl create -f kubernetes-dashboard.yaml
kubectl get svc,pod --all-namespaces | grep dashboard

可以看到kubernetes-dashboard已正常运行。

kube-system   service/kubernetes-dashboard   NodePort    10.108.96.71   <none>        443:30356/TCP   1m
kube-system   pod/kubernetes-dashboard-754f4d5f69-nfvrk   0/1       CrashLoopBackOff   3          1m

12.2 授予Dashboard账户集群管理权限

需要一个管理集群admin的权限，新建kubernetes-dashboard-admin.rbac.yaml文件，内容如下

apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kube-system
---
# Create ClusterRoleBinding
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: kube-system

执行命令

kubectl create -f kubernetes-dashboard-admin.rbac.yaml

找到kubernete-dashboard-admin的token，用户登录使用

执行命令并查看结果

[[email protected] kubernetes]# kubectl -n kube-system get secret | grep admin-user
admin-user-token-b9mpt                           kubernetes.io/service-account-token   3         29s

可以看到名称是kubernetes-dashboard-admin-token-ddskx，使用该名称执行如下命令

[[email protected] kubernetes]# kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | grep admin-user | awk ‘{print $1}‘)
Name:         admin-user-token-b9mpt
Namespace:    kube-system
Labels:       <none>
Annotations:  kubernetes.io/service-account.name=admin-user
              kubernetes.io/service-account.uid=f1247ca8-9173-11e8-bbc3-000c29ea3e30

Type:  kubernetes.io/service-account-token

Data
====
token:      eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJhZG1pbi11c2VyLXRva2VuLWI5bXB0Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6ImFkbWluLXVzZXIiLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC51aWQiOiJmMTI0N2NhOC05MTczLTExZTgtYmJjMy0wMDBjMjllYTNlMzAiLCJzdWIiOiJzeXN0ZW06c2VydmljZWFjY291bnQ6a3ViZS1zeXN0ZW06YWRtaW4tdXNlciJ9.g9F6vn84ds6iVi1TJViWaK1oHMsY0vQoV5Xq8n0nF5WF4uJkkToHxs0nHO4G4u927ZWsMuF0JiTD4rKB0uJcnHdc4GwBN6L2XMceD69YCpunLlgoFOFbu6z9IsZfyvHvFAYbm0Tv4JWBYxkCqmeTKtL1GOtobIs24dvfXk6inn51ZhTAUW_urWvIn8yqckOBJkq7B_wf6EZA0QeNEhhbt_GHPpwq0CMhk4cWHXh_a27y-qKkpu5Cbo_Ux2kUA44o1wmiHgbw4Lh-__KJY3LZmIu9PZzyWyIPaUWlSQ76GXHyOZQ8dw3WRANi9zaEpiwi4e4XXXXXXXXXXXXXXXXXXXXXXX
ca.crt:     1025 bytes
namespace:  11 bytes

记下这串token，等下登录使用，这个token默认是永久的。

12.3 dashboard访问方式

此处推荐API Server方式访问。（谷歌内核浏览器）

12.3.1 `kubectl proxy`方式访问

如下操作在lab1上操作

kubectl proxy --address=0.0.0.0 --disable-filter=true

即可通过浏览器访问: http://192.168.105.92:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/#!/login

注意
仪表盘使用kubectl代理命令不应暴露公开,因为它只允许HTTP连接。域以外的localhost和127.0.0.1将不能登录。在登录页面点击登录按钮什么都不会发生后，跳过登录后，没有任何权限。

此方式只允许开发测试使用。为了便于开发测试，以下配置用于提升默认权限为超级用户权限。

vim kubernetes-dashboard-test.yaml

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

12.3.2 NodePort方式访问

这种访问方式仪表板只建议在单个节点上设置开发环境。

编辑kubernetes-dashboard.yaml文件，添加type: NodePort和nodePort: 30001，暴露Dashboard服务为30001端口，参考如下。

# ------------------- Dashboard Service ------------------- #
kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kube-system
spec:
  type: NodePort  # NodePort登录方式
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 30001  # NodePort登录暴露端口
  selector:
    k8s-app: kubernetes-dashboard

注意
仪表盘可以在master节点上访问，如果是多节点集群，官方文档说应该是使用节点IP和NodePort来访问，但是经过测试，https://<master-ip>:<nodePort> 和 https://<node-ip>:<nodePort>都可以访问。

12.3.3 API Server方式访问

https://<master-ip>:<apiserver-port>/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/

注意
这种方式访问仪表盘的仅仅可能在安装了你的用户证书的浏览器上。与API Server通信可以使用示例所使用的证书kubeconfig文件。

浏览器访问问题：

{
  "kind": "Status",
  "apiVersion": "v1",
  "metadata": {

  },
  "status": "Failure",
  "message": "services \"https:kubernetes-dashboard:\" is forbidden: User \"system:anonymous\" cannot get services/proxy in the namespace \"kube-system\"",
  "reason": "Forbidden",
  "details": {
    "name": "https:kubernetes-dashboard:",
    "kind": "services"
  },
  "code": 403
}

这是因为最新版的k8s默认启用了RBAC，并为未认证用户赋予了一个默认的身份：anonymous。

对于API Server来说，它是使用证书进行认证的，我们需要先创建一个证书：

首先找到kubectl命令的配置文件，默认情况下为/etc/kubernetes/admin.conf，在上文中，我们已经复制到了$HOME/.kube/config中。
然后我们使用client-certificate-data和client-key-data生成一个p12文件，可使用下列命令：

# 生成client-certificate-data
grep ‘client-certificate-data‘ ~/.kube/config | head -n 1 | awk ‘{print $2}‘ | base64 -d >> kubecfg.crt

# 生成client-key-data
grep ‘client-key-data‘ ~/.kube/config | head -n 1 | awk ‘{print $2}‘ | base64 -d >> kubecfg.key

# 生成p12
openssl pkcs12 -export -clcerts -inkey kubecfg.key -in kubecfg.crt -out kubecfg.p12 -name "kubernetes-client"

最后导入上面生成的p12文件，重新打开浏览器，显示出现选择证书选项，选OK，然后就可以看到熟悉的登录界面了。我们可以使用一开始创建的admin-user用户的token进行登录，一切OK。

注意
对于生产系统，我们应该为每个用户应该生成自己的证书，因为不同的用户会有不同的命名空间访问权限。

12.3.4 nginx ingress方式访问

可以动态的更新Nginx配置等，是比较灵活，更为推荐的暴露服务的方式，但也相对比较复杂，业务环境推荐使用。

13. 基础测试

测试容器间的通信和DNS
配置好网络之后，kubeadm会自动部署coredns

如下测试可以在配置kubectl的节点上操作

# 启动名为nginx的容器
kubectl run nginx --replicas=2 --image=nginx:alpine --port=80
# 暴露nginx容器为服务（--type=NodePort/ClusterIP/LoadBalancer，3种类型访问方式不同）
kubectl expose deployment nginx --type=NodePort --name=example-service-nodeport
kubectl expose deployment nginx --name=example-service
# 查看状态
kubectl get deploy
kubectl get pods
kubectl get svc
kubectl describe svc example-service
# DNS解析
kubectl run curl --image=radial/busyboxplus:curl -i --tty
nslookup kubernetes
nslookup example-service
curl example-service
# 访问测试
# 10.103.184.0 为查看svc时获取到的clusterip
curl "10.103.184.0:80"

# 32223 为查看svc时获取到的 nodeport
http://192.168.105.93:32223/
http://192.168.105.94:32223/
# 清理删除
kubectl delete svc example-service example-service-nodeport
kubectl delete deploy nginx curl
# 高可用测试
# 关闭任一master节点测试集群是能否正常执行上一步的基础测试，查看相关信息，不能同时关闭两个节点，因为3个节点组成的etcd集群，最多只能有一个当机。

# 查看组件状态
kubectl get pod --all-namespaces -o wide
kubectl get pod --all-namespaces -o wide | grep lab1
kubectl get pod --all-namespaces -o wide | grep lab2
kubectl get pod --all-namespaces -o wide | grep lab3
kubectl get nodes -o wide
kubectl get deploy
kubectl get pods
kubectl get svc

# 访问测试
CURL_POD=$(kubectl get pods | grep curl | grep Running | cut -d ‘ ‘ -f1)
kubectl exec -it $CURL_POD -- sh --tty
nslookup kubernetes
nslookup example-service
curl example-service

13. 小技巧

忘记初始master节点时的node节点加入集群命令怎么办

# 简单方法
kubeadm token create --print-join-command

# 第二种方法
token=$(kubeadm token generate)
kubeadm token create $token --print-join-command --ttl=0

14. 相关命令

# 查看集群结点状态
kubectl get nodes
# 查看详细结点信息
kubectl describe nodes
# 查看所有pod
kubectl get pods --all-namespaces
# 查看集群服务状态
kubectl get svc --all-namespaces
# 查看集群运行在那些ip上
kubectl cluster-info
# 查看master的各种token
kubectl get secret -n kube-system
# 查看某一个特定的token
kubectl describe secret/[token name] -n kube-system

参考文档：
[1] https://kubernetes.io/docs/setup/independent/install-kubeadm/
[2] https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/
[3] https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-init/
[4] https://kubernetes.io/docs/setup/independent/high-availability/
[5] https://sealyun.com/post/k8s-ipvs/
[6] http://www.maogx.win/posts/33/
[7] https://github.com/opsnull/follow-me-install-kubernetes-cluster
[8] https://github.com/xizhibei/blog/issues/64
[9] https://www.cnblogs.com/RainingNight/p/deploying-k8s-dashboard-ui.html

原文地址：http://blog.51cto.com/ygqygq2/2153241

时间： 2024-11-07 01:46:20

centos7使用kubeadm安装kubernetes 1.11版本多主高可用

1. 实验环境说明

2. 准备yum源

2. 安装配置docker

3. 安装 kubeadm, kubelet 和 kubectl

4. 配置系统相关参数

5. 配置hosts解析

6. 配置haproxy代理和keepalived

7. 配置启动kubelet

8. 配置master

8.1 配置第一个master

8.2 配置第二个master

8.3 配置第三个master

9. 配置使用kubectl

10. 配置使用网络插件

11. 配置node节点加入集群

12. 配置dashboard

12.1 安装Dashboard插件

12.2 授予Dashboard账户集群管理权限

12.3 dashboard访问方式

12.3.1 `kubectl proxy`方式访问

12.3.2 NodePort方式访问

12.3.3 API Server方式访问

12.3.4 nginx ingress方式访问

13. 基础测试

13. 小技巧

14. 相关命令