Kubernetes高可用集群部署
部署架构:
Master 组件:
- kube-apiserver
Kubernetes API,集群的统一入口,各组件协调者,以HTTP API提供接口服务,所有对象资源的增删改查和监听操作都交给APIServer处理后再提交给Etcd存储。
- kube-controller-manager
处理集群中常规后台任务,一个资源对应一个控制器,而ControllerManager就是负责管理这些控制器的。
- kube-scheduler
根据调度算法为新创建的Pod选择一个Node节点。
Node 组件:
- kubelet
kubelet是Master在Node节点上的Agent,管理本机运行容器的生命周期,比如创建容器、Pod挂载数据卷、
下载secret、获取容器和节点状态等工作。kubelet将每个Pod转换成一组容器。
- kube-proxy
在Node节点上实现Pod网络代理,维护网络规则和四层负载均衡工作。
- docker
运行容器。
第三方服务:
- etcd
分布式键值存储系统。用于保持集群状态,比如Pod、Service等对象信息。
下图清晰表明了Kubernetes的架构设计以及组件之间的通信协议。
一、环境规划
角色 |
IP |
组件 |
K8S-MASTER01 |
10.247.74.48 |
kube-apiserver kubelet flannel Nginx keepalived |
K8S-MASTER02 |
10.247.74.49 |
kube-apiserver kubelet flannel Nginx keepalived |
K8S-MASTER03 |
10.247.74.50 |
kube-apiserver kubelet flannel Nginx keepalived |
K8S-NODE01 |
10.247.74.53 |
kubelet |
K8S-NODE02 |
10.247.74.54 |
kubelet |
K8S-NODE03 |
10.247.74.55 |
kubelet |
K8S-NODE04 |
10.247.74.56 |
kubelet |
K8S-VIP |
10.247.74.51 |
软件版本信息
软件 |
版本 |
Linux操作系统 |
Red Hat Enterprise 7.6_x64 |
Kubernetes |
1.14.1 |
Docker |
18.06.3-ce |
Etcd |
3.0 |
Nginx |
17.0 |
1.1系统环境准备(所有节点)
#设置主机名及关闭selinux,swap分区
cat <>/etc/hosts 10.247.74.48 TWDSCPA203V 10.247.74.49 TWDSCPA204V 10.247.74.50 TWDSCPA205V 10.247.74.53 TWDSCPA206V 10.247.74.54 TWDSCPA207V 10.247.74.55 TWDSCPA208V 10.247.74.56 TWDSCPA209V 10.247.74.51 K8S-VIP EOF sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config swapoff -a sed -i 's/\/dev\/mapper\/centos-swap/\#\/dev\/mapper\/centos-swap/g' /etc/fstab systemctl enable ntpd systemctl start ntpd
#设置内核参数
echo "* soft nofile 32768" >> /etc/security/limits.conf echo "* hard nofile 65535" >> /etc/security/limits.conf echo "* soft nproc 32768" >> /etc/security/limits.conf echo "* hadr nproc 65535" >> /etc/security/limits.conf cat > /etc/sysctl.d/k8s.conf <
#加载IPVS模块
在所有的Kubernetes节点执行以下脚本(若内核大于4.19替换nf_conntrack_ipv4为nf_conntrack):
cat > /etc/sysconfig/modules/ipvs.modules <
#执行脚本
chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4
#安装ipvs相关管理软件
yum install ipset ipvsadm -y reboot
1.2安装Docker(所有节点)
# Step 1: 安装必要的一些系统工具
yum install -y yum-utils device-mapper-persistent-data lvm2
#sSep 2:安装ddocker
yum update -y && yum install -y docker-ce-18.06.3.ce
# Step 3: 配置docker仓库及镜像存放路径
mkdir -p /mnt/sscp/data/docker cat > /etc/docker/daemon.json <
# Step 4: 重启启Docker服务
systemctl restart docker systemctl enable docker
1.3部署Nginx
一、安装依赖包 yum install -y gcc gcc-c++ pcre pcre-devel zlib zlib-devel openssl openssl-devel 二、从官网下载安装包 wget https://nginx.org/download/nginx-1.16.0.tar.gz 三、解压并安装 tar zxvf nginx-1.16.0.tar.gz cd nginx-1.16.0 ./configure --prefix=/usr/local/nginx --with-http_stub_status_module --with-http_ssl_module --with-http_realip_module --with-http_flv_module --with-http_mp4_module --with-http_gzip_static_module--with-stream --with-stream_ssl_module make && make install 四、配置kube-apiserver反向代理 stream { log_format main '$remote_addr $upstream_addr - [$time_local] $status $upstream_bytes_sent'; access_log /var/log/nginx/k8s-access.log main; upstream k8s-apiserver { server 10.247.74.48:6443; server 10.247.74.49:6443; server 10.247.74.50:6443; } server { listen 0.0.0.0:8443; proxy_pass k8s-apiserver; } } 五、启动nginx服务 /usr/local/sbin/nginx
1.4部署keepalived
一、下载地址: wget https://www.keepalived.org/software/keepalived-2.0.16.tar.gz 二、解压并安装 tar xf keepalived-2.0.16.tar.gz cd keepalived-2.0.16 ./configure --prefix=/usr/local/keepalived make && make install cp /root/keepalived-2.0.16/keepalived/etc/init.d/keepalived /etc/init.d/ cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/ mkdir /etc/keepalived cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/ cp /usr/local/keepalived/sbin/keepalived /usr/sbin/ 二、添加配置文件 vim /etc/keepalived/keepalived.conf MASTER: vrrp_instance VI_1 { state MASTER interface ens32 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.247.74.51/24 } BACKUP: vrrp_instance VI_1 { state BACKUP interface ens32 virtual_router_id 51 priority 90 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.247.74.51/24 }
1.5部署kubeadm(所有节点)
#由于官方源国内无法访问,这里使用阿里云yum源进行替换:
cat </etc/yum.repos.d/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 EOF
#安装kubeadm、kubelet、kubectl,注意这里安装版本v1.14.1:
yum install -y kubelet-1.14.1 kubeadm-1.14.1 kubectl-1.14.1 systemctl enable kubelet && systemctl start kubelet
1.6部署Master节点
初始化参考: https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-init/ https://godoc.org/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta1
创建初始化配置文件 可以使用如下命令生成初始化配置文件
kubeadm config print init-defaults > kubeadm-config.yaml
根据实际部署环境修改信息:
apiVersion: kubeadm.k8s.io/v1beta1 bootstrapTokens: - groups: - system:bootstrappers:kubeadm:default-node-token token: abcdef.0123456789abcdef ttl: 24h0m0s usages: - signing - authentication kind: InitConfiguration localAPIEndpoint: advertiseAddress: 10.247.74.48 bindPort: 6443 nodeRegistration: criSocket: /var/run/dockershim.sock name: cn-hongkong.i-j6caps6av1mtyxyofmrw taints: - effect: NoSchedule key: node-role.kubernetes.io/master --- apiServer: timeoutForControlPlane: 4m0s apiVersion: kubeadm.k8s.io/v1beta1 certificatesDir: /etc/kubernetes/pki clusterName: kubernetes controlPlaneEndpoint: "10.247.74.51:8443" controllerManager: {} dns: type: CoreDNS etcd: local: dataDir: /var/lib/etcd imageRepository: registry.aliyuncs.com/google_containers kind: ClusterConfiguration kubernetesVersion: v1.14.1 networking: dnsDomain: cluster.local podSubnet: "10.244.0.0/16" serviceSubnet: 10.96.0.0/12 scheduler: {} --- apiVersion: kubeproxy.config.k8s.io/v1alpha1 kind: KubeProxyConfiguration featureGates: SupportIPVSProxyMode: true mode: ipvs
配置说明:
controlPlaneEndpoint:为vip地址和haproxy监听端口6444 imageRepository:由于国内无法访问google镜像仓库k8s.gcr.io,这里指定为阿里云镜像仓库registry.aliyuncs.com/google_containers podSubnet:指定的IP地址段与后续部署的网络插件相匹配,这里需要部署flannel插件,所以配置为10.244.0.0/16 mode: ipvs:最后追加的配置为开启ipvs模式。
在集群搭建完成后可以使用如下命令查看生效的配置文件:
kubeadm config images pull --config kubeadm-config.yaml # 通过阿里源预先拉镜像
初始化Master01节点
这里追加tee命令将初始化日志输出到kubeadm-init.log中以备用(可选)。
kubeadm init --config=kubeadm-config.yaml --experimental-upload-certs | tee kubeadm-init.log
该命令指定了初始化时需要使用的配置文件,其中添加–experimental-upload-certs参数可以在后续执行加入节点时自动分发证书文件。
1.7添加其他Master节点
执行以下命令:
kubeadm join 10.247.74.51:8443 --token ocb5tz.pv252zn76rl4l3f6 \ --discovery-token-ca-cert-hash sha256:141bbeb79bf58d81d551f33ace207c7b19bee1cfd7790112ce26a6a300eee5a2 \ --experimental-control-plane --certificate-key 20366c9cdbfdc1435a6f6d616d988d027f2785e34e2df9383f784cf61bab9826
添加上下文:
mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config
1.8添加Node节点
执行以下命令:
kubeadm join 10.247.74.51:8443 --token ocb5tz.pv252zn76rl4l3f6 \ --discovery-token-ca-cert-hash sha256:141bbeb79bf58d81d551f33ace207c7b19bee1cfd7790112ce26a6a300eee5a2
1.9部署flannel并查询集群状态
一、部署flannel
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
二、查看集群状态
# kubectl get node
1.10后续
token默认24h后失效如果有新的node加入可在master上重新生成:
kubeadm token create --print-join-command