kubeadm---高可用安装

时间:2020-03-10
本文章向大家介绍kubeadm---高可用安装，主要包括kubeadm---高可用安装使用实例、应用技巧、基本知识点总结和需要注意事项，具有一定的参考价值，需要的朋友可以参考一下。

1.修改主机名

如何使用hostnamectl set-hostname name来为每台主机设置不同的机器名

#hostnamectl set-hostname k8s-master01

或者使用以下方式对/etc/hosts写入

cat >> /etc/hosts << EOF
192.168.80.10 k8s-master01
192.168.80.20 k8s-master02
192.168.80.30 k8s-master03
192.168.80.40 k8s-node01
192.168.80.50 k8s-node02
192.168.80.100 lbvip
EOF

2.安装依赖包

yum -y install conntrack ntpdate ntp ipvsadm ipset jq iptables curl vim sysstat libseccomp wget lrzsz net-tools git

3.设置防火墙为iptables并设置空规则

systemctl stop firewalld && systemctl disable firewalld
yum -y install iptables-services && systemctl start iptables && systemctl enable iptables && iptables -F && service iptables save

4.对升级的软件包等更新最新

yum update -y

5.关闭SELINUX

swapoff -a && sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
setenforce 0 && sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config

6.调整内核参数，对于K8S

modprobe br_netfilter

cat > kubernetes.conf << EOF
net.bridge.bridge-nf-call-iptables=1
net.bridge.bridge-nf-call-ip6tables=1
net.ipv4.ip_forward=1
net.ipv4.tcp_tw_recycle=0
vm.swappiness=0   #禁止使用swap空间，只有当系统OOM时才允许使用它
vm.overcommit_memory=1   #不检查物理内存是否够用
vm.panic_on_oom=0    #开启OOM
fs.inotify.max_user_instances=8192
fs.inotify.max_user_watches=1048576
fs.file-max=52706963
fs.nr_open=52706963
net.ipv6.conf.all.disable_ipv6=1
net.netfilter.nf_conntrack_max=2310720
EOF

cp kubernetes.conf /etc/sysctl.d/kubernetes.conf
sysctl -p /etc/sysctl.d/kubernetes.conf

7.调整时区

# 设置系统时区为 中国/上海
  timedatectl set-timezone Asia/Shanghai
# 将当前的UTC时间写入硬件时钟
  timedatectl set-local-rtc 0
# 重启依赖于系统时间的服务 
  systemctl restart rsyslog && systemctl restart crond

8.关闭不必要的服务

#CentOS7下，CentOS8.1不需要
  systemctl stop postfix && systemctl disable postfix

9.设置rsyslogd和systemd journald

mkdir /var/log/journal  #持久化保存日志的目录
mkdir /etc/systemd/journald.conf.d
cat > /etc/systemd/journald.conf.d/99-prophet.conf << EOF
[Journal]
# 持久化保存到磁盘
Storage=persistent

# 压缩历史日志
Compress=yes

SyncIntervalSec=5m
RateLimitInterval=30s
RateLimitBurst=1000

# 最大占用空间
SystemMaxUse=10G

# 单日志文件最大 200M
SystemMaxFileSize=200M

# 日志保存时间 2周
MaxRetentionSec=2week

# 不将日志转发到syslog
ForwardToSyslog=no
EOF

systemctl restart systemd-journald

10.升级到最新版本的内核

如果是CentOS7.x系统自带的3.10.x内存存在一些Bugs，导致运行的Docker、Kubernetes不稳定，建议
升级到4.4.x内核及以上的内核
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
yum -y install https://www.elrepo.org/elrepo-release-7.0-4.el7.elrepo.noarch.rpm
# 安装完成后检查/boot/grub2/grub.cfg中对应内核menuentry中是否包含initrd16配置，如果没有，
   再安装一次！
  yum --enablerepo=elrepo-kernel install -y kernel-lt
# 设置开机从新内核启动
  grub2-set-default 'CentOS Linux (4.4.215-1.el7.elrepo.x86_64) 7 (Core)'
  
#重新启动系统
  reboot

11.关闭NUMA

cp /etc/default/grub{,.bak}
vim /etc/default/grub   #在GRUB_CMDLINE_LINUX一行添加'numa=off'参数，如下所示：
  GRUB_CMDLINE_LINUX="crashkernel=auto spectre_v2=retpoline rhgb quiet numa=off"

12.Kube-proxy开启ipvs的前置条件

cat > /etc/sysconfig/modules/ipvs.modules << EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF

chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4

#重启系统
reboot

13.安装软件

#安装docker
yum install -y yum-utils device-mapper-persistent-data lvm2
  
cd /etc/yum.repos.d
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo


# 创建/etc/docker目录
mkdir /etc/docker


#最后/etc/docker/daemon.json文件的内容如下：
cat > /etc/docker/daemon.json << EOF
{
    "exec-opts": ["native.cgroupdriver=systemd"],
    "log-driver": "json-file",
    "log-opts": {
         "max-size": "100m"
    },
    "insecure-registries": ["https://hub.mfyxw.com"],
    "registry-mirrors": ["https://jltw059v.mirror.aliyuncs.com"]
}
EOF

#列出docker-ce版本
yum list docker-ce --showduplicates | sort -r

  yum install -y docker-ce
  yum install -y docker-ce-18.06.3.ce-3.el7
  
mkdir -p /etc/systemd/system/docker.servicd.d

#重启docker服务
systemctl daemon-reload && systemctl restart docker && systemctl enable docker

14.安装haproxy和keepalived软件

yum -y install haproxy keepalived

15.添加haproxy配置文件内容

#在对配置文件修改前先做好原配置文件的备份
mv /etc/haproxy/haproxy.cfg{,.bak}

#对原来的配置文件内容修改如下
cat > /etc/haproxy/haproxy.cfg << EOF
global
  maxconn  2000
  ulimit-n  16384
  log  127.0.0.1 local0 err
  stats timeout 30s

defaults
  log global
  mode  http
  option  httplog
  timeout connect 5000
  timeout client  50000
  timeout server  50000
  timeout http-request 15s
  timeout http-keep-alive 15s

frontend monitor-in
  bind *:33305
  mode http
  option httplog
  monitor-uri /monitor

listen stats
  bind    *:8006
  mode    http
  stats   enable
  stats   hide-version
  stats   uri       /stats
  stats   refresh   30s
  stats   realm     Haproxy\ Statistics
  stats   auth      admin:admin

frontend k8s-master
  bind 0.0.0.0:58443            #此端口地址建议修改大点，以免和prometheu+grafana的端口产生冲突
  bind 127.0.0.1:58443          #此端口地址建议修改大点，以免和prometheu+grafana的端口产生冲突
  mode tcp
  option tcplog
  tcp-request inspect-delay 5s
  default_backend k8s-master

backend k8s-master
  mode tcp
  option tcplog
  option tcp-check
  balance roundrobin
  default-server inter 10s downinter 5s rise 2 fall 2 slowstart 60s maxconn 250 maxqueue 256 weight 100
  #如下内容的主机名和IP地址请按你实际环境的来填写
  server k8s-master01   192.168.80.10:6443  check      
  server k8s-master02   192.168.80.20:6443  check
  server k8s-master03   192.168.80.30:6443  check
EOF

 #把修改好的haproxy.cfg文件分别复制到另外二个master节点的/etc/haproxy/目录下
 scp -r /etc/haproxy/haproxy.cfg k8s-master01:/etc/haproxy/
 scp -r /etc/haproxy/haproxy.cfg k8s-master02:/etc/haproxy/
 scp -r /etc/haproxy/haproxy.cfg k8s-master03:/etc/haproxy/

16.添加keepalived配置文件

#对原有的keepalived配置文件做备份
mv /etc/keepalived/keepalived.conf{,.bak}

#直接复制如下内容到shell中回车即可(已经重新对keepalived.conf文件修改)
cat > /etc/keepalived/keepalived.conf << EOF
! Configuration File for keepalived
global_defs {
    router_id LVS_DEVEL
}
vrrp_script chk_apiserver {
    script "/etc/keepalived/check_apiserver.sh"
    interval 2
    weight -5
    fall 3
    rise 2
}
vrrp_instance VI_1 {
    state MASTER
    interface ens33
    mcast_src_ip 192.168.80.10   #此处请填写相对应的本地的IP地址，IP不能相同，每个master节点的请另行修改
    virtual_router_id 51
    priority 102             #优先级高的能优先获得vip地址，优先级不能相同，每个master节点的请另行修改
    advert_int 2
    authentication {
        auth_type PASS
        auth_pass K8SHA_KA_AUTH
    }
    virtual_ipaddress {
        192.168.80.100         #此处填写你要设定的VIP地址
    }
#    track_script {
#       chk_apiserver
#    }
}
EOF

#复制keepalived.conf文件到另外二个master节点,复制过去后请自动修改IP地址和优先级，VIP地址不需要修改
scp -r /etc/keepalived/keepalived.conf k8s-master02:/etc/keepalived/
scp -r /etc/keepalived/keepalived.conf k8s-master03:/etc/keepalived/

17.为keepalived添加检测脚本

cat > /etc/keepalived/check_apiserver.sh << EOF
#!/bin/bash

function check_apiserver() {
  for ((i=0;i<5;i++));do
    apiserver_job_id=$(pgrep kube-apiserver)
    if [[ ! -z $apiserver_job_id ]];then
       return
    else
       sleep 2
    fi
    apiserver_job_id=0
  done
}
# 1: running 0: stopped
check_apiserver
if [[ $apiserver_job_id -eq 0 ]]; then
    /usr/bin/systemctl stop keepalived
    exit 1
else
    exit 0
fi
EOF

#对检测脚本添加执行权限
chmod a+x /etc/keepalived/check_apiserver.sh

#把检测脚本分别复制到另外的master节点对应的/etc/keepalived目录下
scp -r /etc/keepalived/check_apiserver.sh k8s-master02:/etc/keepalived/
scp -r /etc/keepalived/check_apiserver.sh k8s-master03:/etc/keepalived/

18.把haproxy和keepalived服务启动

systemctl enable --now haproxy && systemctl enable --now keepalived

#查看haproxy和keepalived的服务状态
systemctl status haproxy keepalived

19.安装kubeadm主从

#所有节点都需要导入yum源(包括master和node)
cat << EOF > /etc/yum.repos.d/kubernetes.repo
[Kubernetes]
name=Kubernetes repo
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enable=1
gpgcheck=1
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

#安装kubeadm,kubectl kubelet(包括master和node节点)
yum -y install kubeadm-1.17.1 kubectl-1.17.1 kubelet-1.17.1

#也可以直接安装最新版本的
yum -y install kubeadm kubectl kubelet

#设置kubelet开机自启(包括master和node节点)
systemctl enable kubelet.service

20.导入所需要的镜像

#将下载的镜像包上传到master节点并解压导入(原需要的镜像需要**上网下载才行，故都是通过把所需要的镜像自行去阿里找并pull回来打包)

#Master节点：把打包的镜像kubeadm-basic.images.tar.gz上传到master节点解压
tar xf kubeadm-basic.images.tar.gz
cd kubeadm-basix.images

#通过命令把镜像导入到master节点，也可以写成脚本进行导入
#手动导入方法
docker load -i apiserver_1.17.1.tar && docker load -i etcd_3.4.3-0.tar && docker load -i kube-con-manager_1.17.1.tar && docker load -i proxy_1.17.1.tar && docker load -i coredns_1.6.5.tar && docker load -i flannel.tar && docker load -i pause_3.1.tar && docker load -i scheduler_1.17.1.tar

#Node节点：把打包的镜像kubeadm-basic.images.tar.gz上传到master节点解压
tar xf kubeadm-basic.images.tar.gz
cd kubeadm-basix.images

#通过命令把镜像导入到master节点，也可以写成脚本进行导入
#手动导入方法
docker load -i coredns_1.6.5.tar && docker load -i flannel.tar && docker load -i pause_3.1.tar && docker load -i proxy_1.17.1.tar 


#脚本导入方法
cat > /root/import_image.sh << EOF
ls /root/kubeadm-base.images > /tmp/images-list.txt
cd /root/kubeadm-base.images

for i in $( cat /tmp/images-list.txt )
do
   docker load -i $i
done

rm -fr /tmp/images-list.txt
EOF

#给脚本添加可执行权限
chmod a+x /root/import_image.sh

#执行脚本 
bash /root/import_image.sh

21.生成k8s初始化配置文件

#在获得vip的master节点上生成创始化配置文件
kubeadm config print init-defaults > kubeadm-init.yaml
#出现如下二段文字，忽略(1.17版本会生成默认配置文件会提示)
W0309 10:29:42.003091    2724 validation.go:28] Cannot validate kube-proxy config - no validator is available
W0309 10:29:42.004138    2724 validation.go:28] Cannot validate kubelet config - no validator is available

#对生成的kubeadm-init.yaml文件进行修改
apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
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: 192.168.80.10     #当前master主机的IP地址，请自行修改
  bindPort: 6443
nodeRegistration:
  criSocket: /var/run/dockershim.sock
  name: lbvip
  taints:
  - effect: NoSchedule
    key: node-role.kubernetes.io/master
---
apiServer:
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: "192.168.80.100:58443"  #此项如没有请自行添加，此处请填写你的高可用的VIP地址及端口
controllerManager: {}
dns:
  type: CoreDNS
etcd:
  local:
    dataDir: /var/lib/etcd
imageRepository: k8s.gcr.io  #默认会从k8s.gcr.io下载镜像，需要**上网，此处可以修改为阿里云镜像的地址
#imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers #此处的地址为阿里云镜像地址
kind: ClusterConfiguration
kubernetesVersion: v1.15.1   #版本需要修改为你下载的镜像版本，请自行查阅需要的版本
networking:
  dnsDomain: cluster.local
  podSubnet: 10.244.0.0/16     #此处需要添加pod网络，需要与flanel的yaml上的网段一致，如不一致，请修改
  serviceSubnet: 10.96.0.0/12
scheduler: {}
#在scheduler:{}后面添加如下内容(开启ipvs,如果没有开启ipvs会默认降级为iptables)：
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
featureGates:
  SupportIPVSProxyMode: true
mode: ipvs

#温馨提示：如果不能通过**上网，建议修改为阿里云镜像地址进入下载，请自行查询需要安装哪个版本的

如果没有导入镜像而去网上拉取镜像，可以先使用配置文件进行把镜像拉取下来

kubeadm config images pull --config kubeadm-init.yaml

22.在初始化k8s之前需要确定haproxy和keepalived的服务是否正常

#检查获得vip地址的master节点的haproxy和keepalived的服务是否正常
systemctl status haproxy keepalived

23.使用配置文件初始化集群

#在获得vip的master节点上使用配置文件创始化集群并把日志输入到log文件保存
kubeadm init --config kubeadm-init.yaml | tee kubeadm-init.log

把主master节点的证书都复制到其它二个master节点,编写了一个sh程序来复制

#以下脚本，需要你做了免密登录才能使用
cat > /root/cert.sh << EOF
#！/bin/bash
USER=root
CONTROL_PLANE_IPS="k8s-master02 k8s-master03"
for host in $CONTROL_PLANE_IPS; do
    ssh "${USER}"@${host} "mkdir -p /etc/kubernetes/pki/etcd"
    scp /etc/kubernetes/pki/{ca.crt,ca.key,sa.key,sa.pub,front-proxy-ca.crt,front-proxy-ca.key} "${USER}"@$host:/etc/kubernetes/pki
    scp /etc/kubernetes/pki/etcd/{ca.key,ca.crt} "${USER}"@$host:/etc/kubernetes/pki/etcd/
    scp /etc/kubernetes/admin.conf "${USER}"@$host:/etc/kubernetes
done
EOF

chmod a+x /root/cert.sh
bash /root/cert.sh

#如未做免密登录的请参考如下步骤
  #分别在k8s-master02和k8s-master03节点执行相同操作
    mkdir -pv /etc/kubernetes/pki/etcd
  #把k8s-master01的证书复制到其它的master节点相对应的位置
    scp /etc/kubernetes/pki/{ca.crt,ca.key,sa.key,sa.pub,front-proxy-ca.crt,front-proxy-ca.key} k8s-master02:/etc/kubernetes/pki
    scp /etc/kubernetes/pki/{ca.crt,ca.key,sa.key,sa.pub,front-proxy-ca.crt,front-proxy-ca.key} k8s-master03:/etc/kubernetes/pki
    scp /etc/kubernetes/pki/etcd/{ca.key,ca.crt}  k8s-master02:/etc/kubernetes/pki/etcd/
    scp /etc/kubernetes/pki/etcd/{ca.key,ca.crt}  k8s-master03:/etc/kubernetes/pki/etcd/
    scp /etc/kubernetes/admin.conf k8s-master02:/etc/kubernetes
    scp /etc/kubernetes/admin.conf k8s-master03:/etc/kubernetes

其它主节点加入集群，在使用节点加入的命令添加参数**

#--experimental-control-plane适用于1.14之前加入高可用master节点方案
kubeadmin join vip:端口 --token **** --discovery-token-ca-cert-hash *** --experimental-control-plane

#1.17的master节点高可用方案是如下：
kubeadm join 192.168.80.100:8443 --token **** \
    --discovery-token-ca-cert-hash **** \
    --control-plane

温馨提示：****请参与于自己master节点最后生成的

24.Node节点加入集群

#如下方法是Node节点加入集群
kubeadm join 192.168.80.100:8443 --token **** \
    --discovery-token-ca-cert-hash ****
    
温馨提示：****请参与于自己master节点最后生成的

25.安装flannel网络插件

#去github上的flannel下载好kube-flannel.yaml文件到有vip的主master节点
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

#推荐去阿里云镜像下载flannel回来后打标签
docker pull registry.cn-hangzhou.aliyuncs.com/kube-iamges/flannel:v0.11.0-amd64
docker tage registry.cn-hangzhou.aliyuncs.com/kube-iamges/flannel:v0.11.0-amd64   quay.io/coreos/flannel:v0.11.0-amd64

#通过docker save -o来保存镜像
docker save -o flannel.tar  quay.io/coreos/flannel:v0.11.0-amd64

#把保存后的镜像传到其它的节点上
scp -r flannel.tar k8s-master02:/root/
scp -r flannel.tar k8s-master03:/root/
scp -r flannel.tar k8s-node01:/root/
scp -r flannel.tar k8s-node02:/root/

#把其它的节点上导入flannel镜像
docker load -i flannel.tar

#在获得的高可用vip的主master节点上运行kube-flannel.yaml
kubectl apply -f kube-flannel.yaml

26.测试高可用性

#在master03主节点上运行如下命令，把master01主节点的网络断开
while true; do  sleep 1; kubectl get node;date; done
#会有短暂的时间获取不到信息，之后就一直显示正常

原文地址：https://www.cnblogs.com/Heroge/p/12457513.html

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