Kubeadm HA 1.9 高可用 集群 本地离线部署

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k8s介绍

  • k8s 发展速度很快,目前很多大的公司容器集群都基于该项目,如京东,腾讯,滴滴,瓜子二手车,易宝支付,北森等等。
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  • kubernetes1.9版本发布2017年12月15日,每三个月一个迭代版本, Workloads API成为稳定版本,这消除了很多潜在用户对于该功能稳定性的担忧。还有一个重大更新,就是测试支持了Windows了,这打开了在kubernetes中运行Windows工作负载的大门。
  • CoreDNS alpha可以使用标准工具来安装CoreDNS
  • kube-proxy的IPVS模式进入beta版,为大型集群提供更好的可扩展性和性能。
  • kube-router的网络插件支持,更方便进行路由控制,发布,和安全策略管理

k8s 核心架构

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如架构图

  • k8s 高可用2个核心 ==apiserver master== and ==etcd==
  • ==apiserver master==:(需高可用)集群核心,集群API接口、集群各个组件通信的中枢;集群安全控制;
  • ==etcd== :(需高可用)集群的数据中心,用于存放集群的配置以及状态信息,非常重要,如果数据丢失那么集群将无法恢复;因此高可用集群部署首先就是etcd是高可用集群;
  • kube-scheduler:调度器 (内部自选举)集群Pod的调度中心;默认kubeadm安装情况下--leader-elect参数已经设置为true,保证master集群中只有一个kube-scheduler处于活跃状态;
  • kube-controller-manager: 控制器 (内部自选举)集群状态管理器,当集群状态与期望不同时,kcm会努力让集群恢复期望状态,比如:当一个pod死掉,kcm会努力新建一个pod来恢复对应replicas set期望的状态;默认kubeadm安装情况下--leader-elect参数已经设置为true,保证master集群中只有一个kube-controller-manager处于活跃状态;
  • kubelet: agent node注册apiserver
  • kube-proxy: 每个node上一个,负责service vip到endpoint pod的流量转发,老版本主要通过设置iptables规则实现,新版1.9基于kube-proxy-lvs 实现 更好性能和负载拓展

部署示意图

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  • 集群ha方案,我们力求简单,使用keepalive 监听一个vip来实现,(当节点不可以后,会有vip漂移的切换时长,取决于我们设置timeout切换时长,测试会有10s空档期,如果对高可用更高要求 可以用lvs或者nginx做 4层lb负载 更佳完美,我们力求简单够用,可接受10s的api不可用)
  • etcd和master 测试采用 3节点共用部署,(生成环境可以考虑etcd和master分离或者等kubeadm ha正式版推出)

部署环境

最近在部署k8s 1.9集群遇到一些问题,整理记录,或许有助需要的朋友。
因为kubeadm 简单便捷,所以集群基于该项目部署,目前bete版本不支持ha部署,github说2018年预计发布ha 版本,可我们等不及了 呼之欲来。。。

环境 版本
Centos CentOS Linux release 7.3.1611 (Core)
Kernel Linux etcd-host1 3.10.0-514.el7.x86_64
yum base repo http://mirrors.aliyun.com/repo/Centos-7.repo
yum epel repo http://mirrors.aliyun.com/repo/epel-7.repo
kubectl v1.9.0
kubeadmin v1.9.0
docker 1.12.6
docker localre devhub.beisencorp.com

主机名称 相关信息 备注
etcd-host1 10.129.6.211 master和etcd
etcd-host2 10.129.6.212 master和etcd
etcd-host3 10.129.6.213 master和etcd
Vip-keepalive 10.129.6.220 vip用于高可用

环境部署 (我们使用本地离线镜像)

环境预初始化

  • Centos Mini安装 每台机器root
  • 设置机器名
hostnamectl set-hostname etcd-host1
  • 停防火墙
systemctl stop firewalld
systemctl disable firewalld
systemctl disable firewalld
  • 关闭Swap
swapoff -a 
sed 's/.*swap.*/#&/' /etc/fstab
  • 关闭防火墙
systemctl disable firewalld && systemctl stop firewalld && systemctl status firewalld
  • 关闭Selinux
setenforce  0 
sed -i "s/^SELINUX=enforcing/SELINUX=disabled/g" /etc/sysconfig/selinux 
sed -i "s/^SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config 
sed -i "s/^SELINUX=permissive/SELINUX=disabled/g" /etc/sysconfig/selinux 
sed -i "s/^SELINUX=permissive/SELINUX=disabled/g" /etc/selinux/config 

getenforce
  • 增加DNS
echo nameserver 114.114.114.114>>/etc/resolv.conf
  • 设置内核
cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl -p /etc/sysctl.conf

#若问题
执行sysctl -p 时出现:
sysctl -p
sysctl: cannot stat /proc/sys/net/bridge/bridge-nf-call-ip6tables: No such file or directory
sysctl: cannot stat /proc/sys/net/bridge/bridge-nf-call-iptables: No such file or directory

解决方法:
modprobe br_netfilter
ls /proc/sys/net/bridge

配置keepalived

  • VIP Master 通过控制VIP 来HA高可用(常规方案)
  • 到目前为止,三个master节点 相互独立运行,互补干扰. kube-apiserver作为核心入口, 可以使用keepalived 实现高可用, kubeadm join暂时不支持负载均衡的方式,所以我们
  • 安装
yum install -y keepalived
  • 配置keepalived.conf
cat >/etc/keepalived/keepalived.conf  <<EOL
global_defs {
   router_id LVS_k8s
}

vrrp_script CheckK8sMaster {
    script "curl -k https://10.129.6.220:6443"
    interval 3
    timeout 9
    fall 2
    rise 2
}

vrrp_instance VI_1 {
    state MASTER
    interface ens32
    virtual_router_id 61
    # 主节点权重最高 依次减少
    priority 120
    advert_int 1
    #修改为本地IP 
    mcast_src_ip 10.129.6.211
    nopreempt
    authentication {
        auth_type PASS
        auth_pass sqP05dQgMSlzrxHj
    }
    unicast_peer {
        #注释掉本地IP
        #10.129.6.211
        10.129.6.212
        10.129.6.213
    }
    virtual_ipaddress {
        10.129.6.220/24
    }
    track_script {
        CheckK8sMaster
    }

}
EOL
  • 启动
systemctl enable keepalived && systemctl restart keepalived
  • 结果
[root@etcd-host1 k8s]# systemctl status keepalived
● keepalived.service - LVS and VRRP High Availabilitymonitor
   Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled)
   Active: active (running) since Fri 2018-01-19 10:27:58 CST; 8h ago
 Main PID: 1158 (keepalived)
   CGroup: /system.slice/keepalived.service
           ├─1158 /usr/sbin/keepalived -D
           ├─1159 /usr/sbin/keepalived -D
           └─1161 /usr/sbin/keepalived -D

Jan 19 10:28:00 etcd-host1 Keepalived_vrrp[1161]: Sending gratuitous ARP on ens32 for 10.129.6.220
Jan 19 10:28:05 etcd-host1 Keepalived_vrrp[1161]: VRRP_Instance(VI_1) Sending/queueing gratuitous ARPs on ens32 for 10.129.6.220
  • 依次配置 其他2台从节点master 配置 修改对应节点 ip
  • master01 priority 120
  • master02 priority 110
  • master03 priority 100

Etcd https 集群部署

Etcd 环境准备

#机器名称
etcd-host1:10.129.6.211
etcd-host2:10.129.6.212
etcd-host3:10.129.6.213

#部署环境变量
export NODE_NAME=etcd-host3 #当前部署的机器名称(随便定义,只要能区分不同机器即可)
export NODE_IP=10.129.6.213 # 当前部署的机器 IP
export NODE_IPS="10.129.6.211 10.129.6.212 10.129.6.213" # etcd 集群所有机器 IP
# etcd 集群间通信的IP和端口
export ETCD_NODES=etcd-host1=https://10.129.6.211:2380,etcd-host2=https://10.129.6.212:2380,etcd-host3=https://10.129.6.213:2380

Etcd 证书创建(我们使用https方式)

创建 CA 证书和秘钥

  • 安装cfssl, CloudFlare 的 PKI 工具集 cfssl 来生成 Certificate Authority (CA) 证书和秘钥文件
  • 如果不希望将cfssl工具安装到部署主机上,可以在其他的主机上进行该步骤,生成以后将证书拷贝到部署etcd的主机上即可。本教程就是采取这种方法,在一台测试机上执行下面操作。
wget https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
chmod +x cfssl_linux-amd64
mv cfssl_linux-amd64 /usr/local/bin/cfssl

wget https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64
chmod +x cfssljson_linux-amd64
mv cfssljson_linux-amd64 /usr/local/bin/cfssljson

wget https://pkg.cfssl.org/R1.2/cfssl-certinfo_linux-amd64
chmod +x cfssl-certinfo_linux-amd64
mv cfssl-certinfo_linux-amd64 /usr/local/bin/cfssl-certinfo

生成ETCD的TLS 秘钥和证书

  • 为了保证通信安全,客户端(如 etcdctl) 与 etcd 集群、etcd 集群之间的通信需要使用 TLS 加密,本节创建 etcd TLS 加密所需的证书和私钥。

  • 创建 CA 配置文件:
    cat >  ca-config.json <<EOF
    {
    "signing": {
    "default": {
      "expiry": "8760h"
    },
    "profiles": {
      "kubernetes": {
        "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ],
        "expiry": "8760h"
      }
    }
    }
    }
    EOF
  • ==ca-config.json==:可以定义多个 profiles,分别指定不同的过期时间、使用场景等参数;后续在签名证书时使用某个 profile;
  • ==signing==:表示该证书可用于签名其它证书;生成的 ca.pem 证书中 CA=TRUE;
  • ==server auth==:表示 client 可以用该 CA 对 server 提供的证书进行验证;
  • ==client auth==:表示 server 可以用该 CA 对 client 提供的证书进行验证;
    cat >  ca-csr.json <<EOF
    {
    "CN": "kubernetes",
    "key": {
    "algo": "rsa",
    "size": 2048
    },
    "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "System"
    }
    ]
    }
    EOF
  • "CN":Common Name,kube-apiserver 从证书中提取该字段作为请求的用户名 (User Name);浏览器使用该字段验证网站是否合法;
  • "O":Organization,kube-apiserver 从证书中提取该字段作为请求用户所属的组 (Group);
  • ==生成 CA 证书和私钥==:

cfssl gencert -initca ca-csr.json | cfssljson -bare ca
ls ca*

==创建 etcd 证书签名请求:==

cat > etcd-csr.json <<EOF
{
  "CN": "etcd",
  "hosts": [
    "127.0.0.1",
    "10.129.6.211",
    "10.129.6.212",
    "10.129.6.213"
  ],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "System"
    }
  ]
}
EOF
  • hosts 字段指定授权使用该证书的 etcd 节点 IP;
  • 每个节点IP 都要在里面 或者 每个机器申请一个对应IP的证书

生成 etcd 证书和私钥:

cfssl gencert -ca=ca.pem \
  -ca-key=ca-key.pem \
  -config=ca-config.json \
  -profile=kubernetes etcd-csr.json | cfssljson -bare etcd

ls etcd*

mkdir -p /etc/etcd/ssl
cp etcd.pem etcd-key.pem  ca.pem /etc/etcd/ssl/
#

#其他node
rm -rf /etc/etcd/ssl/*
scp -r /etc/etcd/ssl root@10.129.6.211:/etc/etcd/

scp -r root@10.129.6.211:/root/k8s/etcd/etcd-v3.3.0-rc.1-linux-amd64.tar.gz /root

将生成好的etcd.pem和etcd-key.pem以及ca.pem三个文件拷贝到目标主机的/etc/etcd/ssl目录下。

下载二进制安装文件

https://github.com/coreos/etcd/releases 页面下载最新版本的二进制文件:

wget http://github.com/coreos/etcd/releases/download/v3.1.10/etcd-v3.1.10-linux-amd64.tar.gz

tar -xvf etcd-v3.1.10-linux-amd64.tar.gz

mv etcd-v3.1.10-linux-amd64/etcd* /usr/local/bin

创建 etcd 的 systemd unit 文件

mkdir -p /var/lib/etcd  # 必须先创建工作目录
cat > etcd.service <<EOF
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target
Documentation=https://github.com/coreos

[Service]
Type=notify
WorkingDirectory=/var/lib/etcd/
ExecStart=/usr/local/bin/etcd \\
  --name=${NODE_NAME} \\
  --cert-file=/etc/etcd/ssl/etcd.pem \\
  --key-file=/etc/etcd/ssl/etcd-key.pem \\
  --peer-cert-file=/etc/etcd/ssl/etcd.pem \\
  --peer-key-file=/etc/etcd/ssl/etcd-key.pem \\
  --trusted-ca-file=/etc/etcd/ssl/ca.pem \\
  --peer-trusted-ca-file=/etc/etcd/ssl/ca.pem \\
  --initial-advertise-peer-urls=https://${NODE_IP}:2380 \\
  --listen-peer-urls=https://${NODE_IP}:2380 \\
  --listen-client-urls=https://${NODE_IP}:2379,http://127.0.0.1:2379 \\
  --advertise-client-urls=https://${NODE_IP}:2379 \\
  --initial-cluster-token=etcd-cluster-0 \\
  --initial-cluster=${ETCD_NODES} \\
  --initial-cluster-state=new \\
  --data-dir=/var/lib/etcd
Restart=on-failure
RestartSec=5
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF
  • 指定 etcd 的工作目录和数据目录为 /var/lib/etcd,需在启动服务前创建这个目录;
  • 为了保证通信安全,需要指定 etcd 的公私钥(cert-file和key-file)、Peers 通信的公私钥和 CA 证书(peer-cert-file、peer-key-file、peer-trusted-ca-file)、客户端的CA证书(trusted-ca-file);
  • --initial-cluster-state 值为 new 时,--name 的参数值必须位于 --initial-cluster 列表中;

启动 etcd 服务

mv etcd.service /etc/systemd/system/
systemctl daemon-reload
systemctl enable etcd
systemctl start etcd
systemctl status etcd

验证服务

 etcdctl \
  --endpoints=https://${NODE_IP}:2379  \
  --ca-file=/etc/etcd/ssl/ca.pem \
  --cert-file=/etc/etcd/ssl/etcd.pem \
  --key-file=/etc/etcd/ssl/etcd-key.pem \
  cluster-health

预期结果:

[root@node02 ~]# etcdctl   --endpoints=https://${NODE_IP}:2379    --ca-file=/etc/etcd/ssl/ca.pem   --cert-file=/etc/etcd/ssl/etcd.pem   --key-file=/etc/etcd/ssl/etcd-key.pem   cluster-health
member 18699a64c36a7e7b is healthy: got healthy result from https://10.129.6.213:2379
member 5dbd6a0b2678c36d is healthy: got healthy result from https://10.129.6.211:2379
member 6b1bf02f85a9e68f is healthy: got healthy result from https://10.129.6.212:2379
cluster is healthy

若有失败 或 重新配置

systemctl stop etcd

rm -Rf /var/lib/etcd

rm -Rf /var/lib/etcd-cluster

mkdir -p /var/lib/etcd

systemctl start etcd

k8s 安装

提取k8s rpm 包

  • 默认由于某某出海问题
  • 我们离线导入下rpm 仓库
  • 安装官方YUM 仓库
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://yum.kubernetes.io/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=0
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
       https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF

安装kubeadm kubectl cni

  • 下载镜像(自行搬梯子先获取rpm)
mkdir -p  /root/k8s/rpm
cd /root/k8s/rpm

#安装同步工具
yum install -y yum-utils

#同步本地镜像
yumdownloader kubelet kubeadm kubectl kubernetes-cni docker
scp root@10.129.6.224:/root/k8s/rpm/*  /root/k8s/rpm
  • 离线安装
mkdir -p  /root/k8s/rpm
scp root@10.129.6.211:/root/k8s/rpm/*  /root/k8s/rpm
yum install  /root/k8s/rpm/*.rpm -y
  • 启动k8s
#restart
systemctl enable docker && systemctl restart docker
systemctl enable kubelet && systemctl restart kubelet

镜像获取方法

  • 加速器获取 gcr.io k8s镜像 ,导出,导入镜像 或 上传本地仓库
#国内可以使用daocloud加速器下载相关镜像,然后通过docker save、docker load把本地下载的镜像放到kubernetes集群的所在机器上,daocloud加速器链接如下:
https://www.daocloud.io/mirror#accelerator-doc

#pull 获取
docker pull gcr.io/google_containers/kube-proxy-amd64:v1.9.0

#导出
mkdir -p docker-images
docker save -o docker-images/kube-proxy-amd64  gcr.io/google_containers/kube-proxy-amd64:v1.9.0

#导入
docker load -i /root/kubeadm-ha/docker-images/kube-proxy-amd64
  • 代理或vpn获取 gcr.io k8s镜 ,导出,导入镜像 或 上传本地仓库
自谋生路,天机屋漏

kubelet 指定本地镜像

kubelet 修改 配置以使用本地自定义pause镜像
devhub.beisencorp.com/google_containers/pause-amd64:3.0 替换你的环境镜像

cat > /etc/systemd/system/kubelet.service.d/20-pod-infra-image.conf <<EOF
[Service]
Environment="KUBELET_EXTRA_ARGS=--pod-infra-container-image=devhub.beisencorp.com/google_containers/pause-amd64:3.0"
EOF
systemctl daemon-reload
systemctl restart kubelet

Kubeadm Init 初始化

  • 我们使用config 模板方式来初始化集群,便于我们指定etcd 集群
  • devhub.beisencorp.com 使我们的 测试镜像仓库 可以改成自己或者手动导入每个机器镜像
cat <<EOF > config.yaml 
apiVersion: kubeadm.k8s.io/v1alpha1
kind: MasterConfiguration
etcd:
  endpoints:
  - https://10.129.6.211:2379
  - https://10.129.6.212:2379
  - https://10.129.6.213:2379
  caFile: /etc/etcd/ssl/ca.pem 
  certFile: /etc/etcd/ssl/etcd.pem 
  keyFile: /etc/etcd/ssl/etcd-key.pem
  dataDir: /var/lib/etcd
networking:
  podSubnet: 10.244.0.0/16
kubernetesVersion: 1.9.0
api:
  advertiseAddress: "10.129.6.220"
token: "b99a00.a144ef80536d4344"
tokenTTL: "0s"
apiServerCertSANs:
- etcd-host1
- etcd-host2
- etcd-host3
- 10.129.6.211
- 10.129.6.212
- 10.129.6.213
- 10.129.6.220
featureGates:
  CoreDNS: true
imageRepository: "devhub.beisencorp.com/google_containers"
EOF
  • 初始化集群
kubeadm init --config config.yaml 
  • 结果
To start using your cluster, you need to run the following as a regular user:

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

  kubeadm join --token b99a00.a144ef80536d4344 10.129.6.220:6443 --discovery-token-ca-cert-hash sha256:ebc2f64e9bcb14639f26db90288b988c90efc43828829c557b6b66bbe6d68dfa
  • 查看node
[root@etcd-host1 k8s]# kubectl get node
NAME         STATUS    ROLES     AGE       VERSION
etcd-host1   noReady     master    5h        v1.9.0
[root@etcd-host1 k8s]# kubectl get cs
NAME                 STATUS    MESSAGE              ERROR
scheduler            Healthy   ok                   
controller-manager   Healthy   ok                   
etcd-1               Healthy   {"health": "true"}   
etcd-2               Healthy   {"health": "true"}   
etcd-0               Healthy   {"health": "true"}  
  • 问题记录
如果使用kubeadm初始化集群,启动过程可能会卡在以下位置,那么可能是因为cgroup-driver参数与docker的不一致引起
[apiclient] Created API client, waiting for the control plane to become ready
journalctl -t kubelet -S '2017-06-08'查看日志,发现如下错误
error: failed to run Kubelet: failed to create kubelet: misconfiguration: kubelet cgroup driver: "systemd"
需要修改KUBELET_CGROUP_ARGS=--cgroup-driver=systemd为KUBELET_CGROUP_ARGS=--cgroup-driver=cgroupfs

vi /etc/systemd/system/kubelet.service.d/10-kubeadm.conf
#Environment="KUBELET_CGROUP_ARGS=--cgroup-driver=systemd"
Environment="KUBELET_CGROUP_ARGS=--cgroup-driver=cgroupfs"

systemctl daemon-reload && systemctl restart kubelet

安装网络组件 podnetwork

  • 我们选用kube-router
wget https://github.com/cloudnativelabs/kube-router/blob/master/daemonset/kubeadm-kuberouter.yaml

kubectl apply -f kubeadm-kuberouter.yaml
  • 结果
[root@etcd-host1 k8s]# kubectl get po --all-namespaces
NAMESPACE     NAME                                 READY     STATUS    RESTARTS   AGE
kube-system   coredns-546545bc84-zc5dx             1/1       Running   0          6h
kube-system   kube-apiserver-etcd-host1            1/1       Running   0          6h
kube-system   kube-controller-manager-etcd-host1   1/1       Running   0          6h
kube-system   kube-proxy-pfj7x                     1/1       Running   0          6h
kube-system   kube-router-858b7                    1/1       Running   0          37m
kube-system   kube-scheduler-etcd-host1            1/1       Running   0          6h
[root@etcd-host1 k8s]# 

部署其他Master 节点

  • 拷贝master01 配置 master02 master03
#拷贝pki 证书
mkdir -p /etc/kubernetes/pki
scp -r root@10.129.6.211:/etc/kubernetes/pki /etc/kubernetes

#拷贝初始化配置
scp -r root@10.129.6.211://root/k8s/config.yaml /etc/kubernetes/config.yaml
  • 初始化 master02 master03
#初始化
kubeadm init --config /etc/kubernetes/config.yaml 

部署成功 验证结果

为了测试我们把master 设置为 可部署role

默认情况下,为了保证master的安全,master是不会被调度到app的。你可以取消这个限制通过输入:

kubectl taint nodes --all node-role.kubernetes.io/master-

录制终端验证 结果

asciicast

-验证
[zeming@etcd-host1 k8s]$ kubectl get node
NAME         STATUS    ROLES     AGE       VERSION
etcd-host1   Ready     master    6h        v1.9.0
etcd-host2   Ready     master    5m        v1.9.0
etcd-host3   Ready     master    49s       v1.9.0
[zeming@etcd-host1 k8s]$ kubectl get po --all-namespaces
NAMESPACE     NAME                                 READY     STATUS    RESTARTS   AGE
default       nginx01-d87b4fd74-2445l              1/1       Running   0          1h
default       nginx01-d87b4fd74-7966r              1/1       Running   0          1h
default       nginx01-d87b4fd74-rcbhw              1/1       Running   0          1h
kube-system   coredns-546545bc84-zc5dx             1/1       Running   0          3d
kube-system   kube-apiserver-etcd-host1            1/1       Running   0          3d
kube-system   kube-apiserver-etcd-host2            1/1       Running   0          3d
kube-system   kube-apiserver-etcd-host3            1/1       Running   0          3d
kube-system   kube-controller-manager-etcd-host1   1/1       Running   0          3d
kube-system   kube-controller-manager-etcd-host2   1/1       Running   0          3d
kube-system   kube-controller-manager-etcd-host3   1/1       Running   0          3d
kube-system   kube-proxy-gk95d                     1/1       Running   0          3d
kube-system   kube-proxy-mrzbq                     1/1       Running   0          3d
kube-system   kube-proxy-pfj7x                     1/1       Running   0          3d
kube-system   kube-router-bbgpq                    1/1       Running   0          3h
kube-system   kube-router-v2jbh                    1/1       Running   0          3h
kube-system   kube-router-w4cbb                    1/1       Running   0          3h
kube-system   kube-scheduler-etcd-host1            1/1       Running   0          3d
kube-system   kube-scheduler-etcd-host2            1/1       Running   0          3d
kube-system   kube-scheduler-etcd-host3            1/1       Running   0          3d
[zeming@etcd-host1 k8s]$

主备测试

  • 关闭 主节点 master01 观察切换到 master02 机器
  • master03 一直不管获取node信息 测试高可用
while true; do  sleep 1; kubectl get node;date; done

观察主备VIP切换过程

#观察当Master01主节点关闭后,被节点VIP状态  BACKUP  切换到 MASTER 
[root@etcd-host2 net.d]# systemctl status keepalived
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2018-01-22 13:54:17 CST; 21s ago

Jan 22 13:54:17 etcd-host2 Keepalived_vrrp[15908]: VRRP_Instance(VI_1) Transition to MASTER STATE
Jan 22 13:54:17 etcd-host2 Keepalived_vrrp[15908]: VRRP_Instance(VI_1) Received advert with higher priority 120, ours 110
Jan 22 13:54:17 etcd-host2 Keepalived_vrrp[15908]: VRRP_Instance(VI_1) Entering BACKUP STATE

#切换到 MASTER 
[root@etcd-host2 net.d]# systemctl status keepalived
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2018-01-22 13:54:17 CST; 4min 6s ago

Jan 22 14:03:02 etcd-host2 Keepalived_vrrp[15908]: VRRP_Instance(VI_1) Transition to MASTER STATE
Jan 22 14:03:03 etcd-host2 Keepalived_vrrp[15908]: VRRP_Instance(VI_1) Entering MASTER STATE
Jan 22 14:03:03 etcd-host2 Keepalived_vrrp[15908]: VRRP_Instance(VI_1) setting protocol VIPs.
Jan 22 14:03:03 etcd-host2 Keepalived_vrrp[15908]: Sending gratuitous ARP on ens32 for 10.129.6.220

验证集群高可用

#观察 master01 关机后状态变成NotReady
[root@etcd-host3 ~]# while true; do  sleep 1; kubectl get node;date; done
Tue Jan 22 14:03:16 CST 2018
NAME         STATUS    ROLES     AGE       VERSION
etcd-host1   Ready     master    19m       v1.9.0
etcd-host2   Ready     master    3d        v1.9.0
etcd-host3   Ready     master    3d        v1.9.0
Tue Jan 22 14:03:17 CST 2018
NAME         STATUS     ROLES     AGE       VERSION
etcd-host1   NotReady   master    19m       v1.9.0
etcd-host2   Ready      master    3d        v1.9.0
etcd-host3   Ready      master    3d        v1.9.0

#恢复Master主节点后,出现VIP偏移过来,api恢复
The connection to the server 10.129.6.220:6443 was refused - did you specify the right host or port?
Tue Jan 23 14:14:05 CST 2018
The connection to the server 10.129.6.220:6443 was refused - did you specify the right host or port?
Tue Jan 23 14:14:07 CST 2018
Tue Jan 23 14:14:18 CST 2018
NAME         STATUS     ROLES     AGE       VERSION
etcd-host1   NotReady   master    29m       v1.9.0
etcd-host2   Ready      master    3d        v1.9.0
etcd-host3   Ready      master    3d        v1.9.0
Tue Jan 23 14:14:20 CST 2018
NAME         STATUS    ROLES     AGE       VERSION
etcd-host1   Ready     master    29m       v1.9.0
etcd-host2   Ready     master    3d        v1.9.0
etcd-host3   Ready     master    3d        v1.9.0

参观文档

#k8s 官方文档
https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-init/
#kubeadm ha 项目文档
https://github.com/indiketa/kubeadm-ha
https://github.com/cookeem/kubeadm-ha/blob/master/README_CN.md
https://medium.com/@bambash/ha-kubernetes-cluster-via-kubeadm-b2133360b198
#kubespray 之前的kargo ansible项目
https://github.com/kubernetes-incubator/kubespray/blob/master/docs/ha-mode.md
#若有问题或转载请注明出处 By Zeming

http://xuzeming.top/2018/01/19/K8s-1-9%E5%AE%9E%E8%B7%B5-Kubeadm-HA-1-9-%E9%AB%98%E5%8F%AF%E7%94%A8-%E9%9B%86%E7%BE%A4-%E6%9C%AC%E5%9C%B0%E7%A6%BB%E7%BA%BF%E9%83%A8%E7%BD%B2/