使用kubeadm搭建高可用的K8s集群
参考地址：
kubeadm是官方社区推出的一个用于快速部署kubernetes集群的工具。
这个工具能通过两条指令完成一个kubernetes集群的部署：
# 创建一个 Master 节点
$ kubeadm init
# 将一个 Node 节点加入到当前集群中
$ kubeadm join
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
- 可以访问外网，需要拉取镜像，如果服务器不能上网，需要提前下载镜像并导入节点
- 禁止swap分区
2. 准备环境
| 角色 | IP |
|---|---|
| k8smaster1 | 192.168.214.128 |
| k8smaster2 | 192.168.214.127 |
| k8snode1 | 192.168.214.129 |
| k8snode2 | 192.168.214.130 |
| k8s-vip（虚拟ip） | 192.168.214.158 |
# 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld
# 关闭selinux
sed -i 's/enforcing/disabled/' /etc/selinux/config # 永久
setenforce 0 # 临时
# 关闭swap
swapoff -a # 临时
vim /etc/fstab # 编辑这个文件， 将下面这句注释掉
#/dev/mapper/cl-swap swap swap defaults 0 0
# 重启生效,swap 将被永久关闭
systemctl reboot
# 根据规划设置主机名
hostnamectl set-hostname <hostname>
# 在master添加hosts
cat >> /etc/hosts << EOF
192.168.214.158 master.k8s.io k8s-vip
192.168.214.128 master01.k8s.io k8smaster1
192.168.214.127 master02.k8s.io k8smaster2
192.168.214.129 node01.k8s.io k8snode1
192.168.214.130 node02.k8s.io k8snode2
EOF
# 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 = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system # 生效
# 时间同步
yum install ntpdate -y
ntpdate time.windows.com
3. 所有master节点部署keepalived
3.1 安装相关包和keepalived
yum install -y conntrack-tools libseccomp libtool-ltdl
yum install -y keepalived
3.2配置master节点
master1节点配置
cat > /etc/keepalived/keepalived.conf <<EOF
! Configuration File for keepalived
global_defs {
router_id k8s
}
vrrp_script check_haproxy {
script "killall -0 haproxy"
interval 3
weight -2
fall 10
rise 2
}
vrrp_instance VI_1 {
state MASTER
interface ens33 #此处改成你自己的网卡名称，https://www.cnblogs.com/lxmzq/articles/12627875.html 可查如何查看网卡信息
virtual_router_id 51
priority 250
advert_int 1
authentication {
auth_type PASS
auth_pass ceb1b3ec013d66163d6ab
}
virtual_ipaddress {
192.168.214.158 # 此处需要改成你自己的虚拟IP（VIP）
}
track_script {
check_haproxy
}
}
EOF
master2节点配置
cat > /etc/keepalived/keepalived.conf <<EOF
! Configuration File for keepalived
global_defs {
router_id k8s
}
vrrp_script check_haproxy {
script "killall -0 haproxy"
interval 3
weight -2
fall 10
rise 2
}
vrrp_instance VI_1 {
state BACKUP
interface ens33 # 换成你自己的网卡信息
virtual_router_id 51
priority 200
advert_int 1
authentication {
auth_type PASS
auth_pass ceb1b3ec013d66163d6ab
}
virtual_ipaddress {
192.168.214.158 # 换成你自己的虚拟IP（VIP）
}
track_script {
check_haproxy
}
}
EOF
3.3 启动和检查
在两台master节点都执行
# 启动keepalived
$ systemctl start keepalived.service
设置开机启动
$ systemctl enable keepalived.service
# 查看启动状态
$ systemctl status keepalived.service # 状态为： Active: active (running) 表未运行成功
启动后查看master1的网卡信息
ip a s ens33 # 发现网卡中多了一个虚拟IP 192.168.214.158，而Master没有，因为master1才有虚拟IP
4. 部署haproxy（所有master）
4.1 安装
yum install -y haproxy
4.2 配置
两台master节点的配置均相同，配置中声明了后端代理的两个master节点服务器，指定了haproxy运行的端口为16443等，因此16443端口为集群的入口
cat > /etc/haproxy/haproxy.cfg << EOF
#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
# to have these messages end up in /var/log/haproxy.log you will
# need to:
# 1) configure syslog to accept network log events. This is done
# by adding the '-r' option to the SYSLOGD_OPTIONS in
# /etc/sysconfig/syslog
# 2) configure local2 events to go to the /var/log/haproxy.log
# file. A line like the following can be added to
# /etc/sysconfig/syslog
#
# local2.* /var/log/haproxy.log
#
log 127.0.0.1 local2
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
daemon
# turn on stats unix socket
stats socket /var/lib/haproxy/stats
#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
mode http
log global
option httplog
option dontlognull
option http-server-close
option forwardfor except 127.0.0.0/8
option redispatch
retries 3
timeout http-request 10s
timeout queue 1m
timeout connect 10s
timeout client 1m
timeout server 1m
timeout http-keep-alive 10s
timeout check 10s
maxconn 3000
#---------------------------------------------------------------------
# kubernetes apiserver frontend which proxys to the backends
#---------------------------------------------------------------------
frontend kubernetes-apiserver
mode tcp
bind *:16443
option tcplog
default_backend kubernetes-apiserver
#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
backend kubernetes-apiserver
mode tcp
balance roundrobin
server master01.k8s.io 192.168.44.155:6443 check
server master02.k8s.io 192.168.44.156:6443 check
#---------------------------------------------------------------------
# collection haproxy statistics message
#---------------------------------------------------------------------
listen stats
bind *:1080
stats auth admin:awesomePassword
stats refresh 5s
stats realm HAProxy\ Statistics
stats uri /admin?stats
EOF
4.3 启动和检查
两台master都启动
# 设置开机启动
$ systemctl enable haproxy && systemctl start haproxy
# 查看启动状态
$ systemctl status haproxy # 状态为： Active: active (running) 表未运行成功
检查端口
netstat -lntup|grep haproxy # yum -y install net-tools 安装netstat
5. 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。
5.1 安装Docker
# wget 安装：yum install wget -y
$ wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
$ yum -y install docker-ce-18.06.1.ce-3.el7
$ systemctl enable docker && systemctl start docker
$ docker --version
Docker version 18.06.1-ce, build e68fc7a
$ cat > /etc/docker/daemon.json << EOF
{
"registry-mirrors": ["http://hub-mirror.c.163.com", "https://registry.docker-cn.com","https://docker.mirrors.ustc.edu.cn"]
}
EOF
# 此时需要重启docker
$ systemctl restart docker
5.2 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=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
5.3 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-1.18.0 kubeadm-1.18.0 kubectl-1.18.0
$ systemctl enable kubelet
6. 部署Kubernetes Master
6.1 创建kubeadm配置文件
在具有vip的master上操作，这里为master1
$ mkdir /usr/local/kubernetes/manifests -p
$ cd /usr/local/kubernetes/manifests/
$ vim kubeadm-config.yaml
#kubeadm-config.yaml
apiServer:
certSANs:
- k8smaster1
- k8smaster2
- master.k8s.io
- 192.168.214.158
- 192.168.214.127
- 192.168.214.128
- 127.0.0.1
extraArgs:
authorization-mode: Node,RBAC
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: stable
controlPlaneEndpoint: "master.k8s.io:16443"
bootstrapTokens:
- groups:
- system:bootstrappers:kubeadm:default-node-token
token: abcdef.0123456789abcdef
ttl: 24h0m0s
usages:
- signing
- authentication
kind: InitConfiguration
localAPIEndpoint:
# 修改为主节点 IP
advertiseAddress: 192.168.214.128
bindPort: 6443
nodeRegistration:
criSocket: /var/run/dockershim.sock
#换成你的主节点master1的名称
name: k8smaster1
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
# 国内不能访问 Google，修改为阿里云
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
# 修改版本号
kubernetesVersion: v1.18.0
networking:
dnsDomain: cluster.local
# 配置 POD 所在网段为我们虚拟机不重叠的网段（这里用的是 Flannel 默认网段）
podSubnet: "10.244.0.0/16"
serviceSubnet: 10.96.0.0/12
scheduler: {}
复制到Linux上时，把注释去掉！！
6.2 在master1节点执行
# 如果之前已经安装了k8s,可以进行重置操作再进行如下操作：kubeadm reset
$ kubeadm init --config kubeadm-config.yaml #执行过程有点慢，喝杯茶，放个水
按照提示配置环境变量，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
$ kubectl get nodes
$ kubectl get pods -n kube-system
按照提示保存以下内容，一会要使用：
kubeadm join master.k8s.io:16443 --token jv5z7n.3y1zi95p952y9p65 \
--discovery-token-ca-cert-hash sha256:403bca185c2f3a4791685013499e7ce58f9848e2213e27194b75a2e3293d8812 \
--control-plane
查看集群状态
kubectl get cs
kubectl get pods -n kube-system
7.安装集群网络
从官方地址获取到flannel的yaml，在master1上执行
mkdir flannel
cd flannel
wget -c https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
安装flannel网络
kubectl apply -f kube-flannel.yml
检查
kubectl get pods -n kube-system
8、master2节点加入集群
8.1 复制密钥及相关文件
从master1复制密钥及相关文件到master2,过程中，可能需要输入登录账号与密码
$ ssh [email protected] mkdir -p /etc/kubernetes/pki/etcd
$ scp /etc/kubernetes/admin.conf [email protected]:/etc/kubernetes
$ scp /etc/kubernetes/pki/{ca.*,sa.*,front-proxy-ca.*} [email protected]:/etc/kubernetes/pki
$ scp /etc/kubernetes/pki/etcd/ca.* [email protected]:/etc/kubernetes/pki/etcd
8.2 master2加入集群
执行在master1上init后输出的join命令,需要带上参数--control-plane表示把master控制节点加入集群
$ sysctl -w net.ipv4.ip_forward=1
#在master2上执行
$ kubeadm join 192.168.214.128:6443 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:e88668002525660857ee0d5a3aac5251f42825c1256bc96527603fff9a9fe548 --control-plane
检查状态
kubectl get node
kubectl get pods --all-namespaces
9. 加入Kubernetes Node
在node1上执行
向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：
kubeadm join master.k8s.io:16443 --token ckf7bs.30576l0okocepg8b --discovery-token-ca-cert-hash sha256:19afac8b11182f61073e254fb57b9f19ab4d798b70501036fc69ebef46094aba
集群网络重新安装，因为添加了新的node节点
检查状态
kubectl get node
kubectl get pods --all-namespaces
10. 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 nginx --image=nginx
$ kubectl expose deployment nginx --port=80 --type=NodePort
$ kubectl get pod,svc
访问地址：http://NodeIP:Port