# Kubernetes搭建高可用集群
# 前言
之前我们搭建的集群，只有一个master节点，当master节点宕机的时候，通过node将无法继续访问，而master主要是管理作用，所以整个集群将无法提供服务
# 高可用集群
下面我们就需要搭建一个多master节点的高可用集群，不会存在单点故障问题
但是在node 和 master节点之间，需要存在一个 LoadBalancer组件，作用如下：
- 负载
- 检查master节点的状态
对外有一个统一的VIP：虚拟ip来对外进行访问
# 高可用集群技术细节
高可用集群技术细节如下所示：
- keepalived：配置虚拟ip，检查节点的状态
- haproxy：负载均衡服务【类似于nginx】
- apiserver：
- controller：
- manager：
- scheduler：
# 高可用集群步骤
我们采用2个master节点，一个node节点来搭建高可用集群，下面给出了每个节点需要做的事情
# 初始化操作
我们需要在这三个节点上进行操作
# 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld
# 关闭selinux
# 永久关闭
sed -i 's/enforcing/disabled/' /etc/selinux/config
# 临时关闭
setenforce 0
# 关闭swap
# 临时
swapoff -a
# 永久关闭
sed -ri 's/.*swap.*/#&/' /etc/fstab
# 根据规划设置主机名【master1节点上操作】
hostnamectl set-hostname master1
# 根据规划设置主机名【master2节点上操作】
hostnamectl set-hostname master1
# 根据规划设置主机名【node1节点操作】
hostnamectl set-hostname node1
# r添加hosts
cat >> /etc/hosts << EOF
192.168.44.158 k8smaster
192.168.44.155 master01.k8s.io master1
192.168.44.156 master02.k8s.io master2
192.168.44.157 node01.k8s.io node1
EOF
# 将桥接的IPv4流量传递到iptables的链【3个节点上都执行】
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
# 生效
sysctl --system
# 时间同步
yum install ntpdate -y
ntpdate time.windows.com
# 部署keepAlived
下面我们需要在所有的master节点【master1和master2】上部署keepAlive
# 安装相关包
# 安装相关工具
yum install -y conntrack-tools libseccomp libtool-ltdl
# 安装keepalived
yum install -y keepalived
# 配置master节点
添加master1的配置
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
virtual_router_id 51
priority 250
advert_int 1
authentication {
auth_type PASS
auth_pass ceb1b3ec013d66163d6ab
}
virtual_ipaddress {
192.168.44.158
}
track_script {
check_haproxy
}
}
EOF
添加master2的配置
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
virtual_router_id 51
priority 200
advert_int 1
authentication {
auth_type PASS
auth_pass ceb1b3ec013d66163d6ab
}
virtual_ipaddress {
192.168.44.158
}
track_script {
check_haproxy
}
}
EOF
# 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
启动后查看master的网卡信息
ip a s ens33
# 部署haproxy
haproxy主要做负载的作用，将我们的请求分担到不同的node节点上
# 安装
在两个master节点安装 haproxy
# 安装haproxy
yum install -y haproxy
# 启动 haproxy
systemctl start haproxy
# 开启自启
systemctl enable haproxy
启动后，我们查看对应的端口是否包含 16443
netstat -tunlp | grep haproxy
# 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
# 安装Docker、Kubeadm、kubectl
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
# 安装Docker
首先配置一下Docker的阿里yum源
cat >/etc/yum.repos.d/docker.repo<<EOF
[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
EOF
然后yum方式安装docker
# yum安装
yum -y install docker-ce
# 查看docker版本
docker --version
# 启动docker
systemctl enable docker
systemctl start docker
配置docker的镜像源
cat >> /etc/docker/daemon.json << EOF
{
"registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
}
EOF
然后重启docker
systemctl restart docker
# 添加kubernetes软件源
然后我们还需要配置一下yum的k8s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
# 安装kubeadm，kubelet和kubectl
由于版本更新频繁，这里指定版本号部署：
# 安装kubelet、kubeadm、kubectl，同时指定版本
yum install -y kubelet-1.18.0 kubeadm-1.18.0 kubectl-1.18.0
# 设置开机启动
systemctl enable kubelet
# 部署Kubernetes Master【master节点】
# 创建kubeadm配置文件
在具有vip的master上进行初始化操作，这里为master1
# 创建文件夹
mkdir /usr/local/kubernetes/manifests -p
# 到manifests目录
cd /usr/local/kubernetes/manifests/
# 新建yaml文件
vi kubeadm-config.yaml
yaml内容如下所示：
apiServer:
certSANs:
- master1
- master2
- master.k8s.io
- 192.168.44.158
- 192.168.44.155
- 192.168.44.156
- 127.0.0.1
extraArgs:
authorization-mode: Node,RBAC
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta1
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: "master.k8s.io:16443"
controllerManager: {}
dns:
type: CoreDNS
etcd:
local:
dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: v1.16.3
networking:
dnsDomain: cluster.local
podSubnet: 10.244.0.0/16
serviceSubnet: 10.1.0.0/16
scheduler: {}
然后我们在 master1 节点执行
kubeadm init --config kubeadm-config.yaml
执行完成后，就会在拉取我们的进行了【需要等待...】
按照提示配置环境变量，使用kubectl工具
# 执行下方命令
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
# 查看节点
kubectl get nodes
# 查看pod
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
--control-plane ： 只有在添加master节点的时候才有
查看集群状态
# 查看集群状态
kubectl get cs
# 查看pod
kubectl get pods -n kube-system
# 安装集群网络
从官方地址获取到flannel的yaml，在master1上执行
# 创建文件夹
mkdir flannel
cd flannel
# 下载yaml文件
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
# master2节点加入集群
# 复制密钥及相关文件
从master1复制密钥及相关文件到master2
# ssh root@192.168.44.156 mkdir -p /etc/kubernetes/pki/etcd
# scp /etc/kubernetes/admin.conf root@192.168.44.156:/etc/kubernetes
# scp /etc/kubernetes/pki/{ca.*,sa.*,front-proxy-ca.*} root@192.168.44.156:/etc/kubernetes/pki
# scp /etc/kubernetes/pki/etcd/ca.* root@192.168.44.156:/etc/kubernetes/pki/etcd
# 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
kubeadm join master.k8s.io:16443 --token ckf7bs.30576l0okocepg8b --discovery-token-ca-cert-hash sha256:19afac8b11182f61073e254fb57b9f19ab4d798b70501036fc69ebef46094aba --control-plane
检查状态
kubectl get node
kubectl get pods --all-namespaces
# 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
# 测试kubernetes集群
在Kubernetes集群中创建一个pod，验证是否正常运行：
# 创建nginx deployment
kubectl create deployment nginx --image=nginx
# 暴露端口
kubectl expose deployment nginx --port=80 --type=NodePort
# 查看状态
kubectl get pod,svc
然后我们通过任何一个节点，都能够访问我们的nginx页面