作者：https://github.com/daemon365/p/18592136
为什么要做高可用
在生产环境中，kubernetes 集群中会多多个 master 节点，每个 master 节点上都会部署 kube-apiserver 服务，实现高可用。但是 client 访问 kube-apiserver 时，需要指定 ip 或者域名，这样会出现单点故障。官方推荐的做法是使用一个负载均衡器，将多个 kube-apiserver 服务负载均衡，实现高可用，但很多时候我们是没有这个条件的。这时候就得想想办法了，比如 nignx 转发，但是 nginx 也是单点。域名的方式，但是这种方式生效时间较长，不太适合紧急情况。所以这里介绍一种使用 keepalived + haproxy 的方式实现 kube-apiserver 的高可用。这是一共公用 IP 的方式，当主节点宕机时，VIP 会自动切换到备节点，实现高可用。
环境准备
- master1: 192.168.31.203
- master2: 192.168.31.34
- master3: 192.168.31.46
- worker1: 192.168.31.25
- VIP （虚拟IP）: 192.168.31.230
安装
| | sudo apt install keepalived haproxy |
| --- | --- |
| | |
| | systemctl enable haproxy |
| | systemctl restart haproxy |
| | |
| | systemctl enable keepalived |
| | # 没有配置会出现错误 不用管 |
| | systemctl restart keepalived |
配置 keepalived
配置文件
编辑 keepalived 配置文件
编辑 /etc/keepalived/keepalived.conf
master1：
| | # 健康检查 查看 haproxy 的进程在不在 |
| --- | --- |
| | vrrp_script chk_haproxy { |
| | script "killall -0 haproxy" |
| | interval 2 # 多少秒教程一次 |
| | weight 3 # 成功了优先级加多少 |
| | } |
| | |
| | vrrp_instance haproxy-vip { |
| | state MASTER # MASTER / BACKUP 1 MASTER 2 BACKUP |
| | priority 100 # 优先级 强的机器高一些 三台master 分别 100 99 98 |
| | interface enp0s3 # 网卡名称 |
| | virtual_router_id 51 # 路由 ip 默认就好 |
| | advert_int 1 # keepalived 之间广播频率 秒 |
| | authentication { |
| | auth_type PASS |
| | auth_pass test_k8s |
| | } |
| | unicast_src_ip 192.168.31.203 # 自己和其他 keepalived 通信地址 |
| | unicast_peer { |
| | 192.168.31.34 # master2 的 IP 地址 |
| | 192.168.31.46 # master3 的 IP 地址 |
| | } |
| | |
| | virtual_ipaddress { |
| | 192.168.31.230 # 这里必须和其他所有的ip 在一个局域网下 |
| | } |
| | |
| | track_script { |
| | chk_haproxy |
| | } |
| | } |
master2：
| | vrrp_script chk_haproxy { |
| --- | --- |
| | script "killall -0 haproxy" |
| | interval 2 |
| | weight 3 |
| | } |
| | |
| | vrrp_instance haproxy-vip { |
| | state BACKUP |
| | priority 99 |
| | interface enp0s3 |
| | virtual_router_id 51 |
| | advert_int 1 |
| | authentication { |
| | auth_type PASS |
| | auth_pass test_k8s |
| | } |
| | unicast_src_ip 192.168.31.34 |
| | unicast_peer { |
| | 192.168.31.203 |
| | 192.168.31.46 |
| | } |
| | |
| | virtual_ipaddress { |
| | 192.168.31.230 |
| | } |
| | |
| | track_script { |
| | chk_haproxy |
| | } |
| | } |
| | |
master3：
| | vrrp_script chk_haproxy { |
| --- | --- |
| | script "killall -0 haproxy" |
| | interval 2 |
| | weight 3 |
| | } |
| | |
| | vrrp_instance haproxy-vip { |
| | state BACKUP |
| | priority 98 |
| | interface enp0s3 |
| | virtual_router_id 51 |
| | advert_int 1 |
| | authentication { |
| | auth_type PASS |
| | auth_pass test_k8s |
| | } |
| | unicast_src_ip 192.168.31.46 |
| | unicast_peer { |
| | 192.168.31.203 |
| | 192.168.31.34 |
| | } |
| | |
| | virtual_ipaddress { |
| | 192.168.31.230 |
| | } |
| | |
| | track_script { |
| | chk_haproxy |
| | } |
| | } |
| | |
测试
重启所有几点的 keepalived ， 虚拟 ip 会在节点 master 上，因为他的优先级高。
| | # master 1 |
| --- | --- |
| | ip a show enp0s3 |
| | 2: enp0s3: mtu 1500 qdisc fq_codel state UP group default qlen 1000 |
| | link/ether 08:00:27:ca:59:86 brd ff:ff:ff:ff:ff:ff |
| | inet 192.168.31.203/24 metric 100 brd 192.168.31.255 scope global dynamic enp0s3 |
| | valid_lft 41983sec preferred_lft 41983sec |
| | inet 192.168.31.230/32 scope global enp0s3 |
| | valid_lft forever preferred_lft forever |
| | inet6 fe80::a00:27ff:feca:5986/64 scope link |
| | valid_lft forever preferred_lft forever |
现在我们关掉 master1 的 haproxy 或者 keepalived
| | systemctl stop haproxy |
| --- | --- |
| | # 再查看网络信息 发现虚拟ip 没了 |
| | ip a show enp0s3 |
| | 2: enp0s3: mtu 1500 qdisc fq_codel state UP group default qlen 1000 |
| | link/ether 08:00:27:ca:59:86 brd ff:ff:ff:ff:ff:ff |
| | inet 192.168.31.203/24 metric 100 brd 192.168.31.255 scope global dynamic enp0s3 |
| | valid_lft 41925sec preferred_lft 41925sec |
| | inet6 fe80::a00:27ff:feca:5986/64 scope link |
| | valid_lft forever preferred_lft forever |
| | |
| | # 在优先级第二高的 master IP 上看下网络 |
| | ip a show enp0s3 |
| | 2: enp0s3: mtu 1500 qdisc fq_codel state UP group default qlen 1000 |
| | link/ether 08:00:27:11:af:4f brd ff:ff:ff:ff:ff:ff |
| | inet 192.168.31.34/24 metric 100 brd 192.168.31.255 scope global dynamic enp0s3 |
| | valid_lft 41857sec preferred_lft 41857sec |
| | inet 192.168.31.230/32 scope global enp0s3 |
| | valid_lft forever preferred_lft forever |
| | inet6 fe80::a00:27ff:fe11:af4f/64 scope link |
| | valid_lft forever preferred_lft forever |
| | |
| | # 启动 master1 的 haproxy ip就会回来 |
配置 haproxy
把 16443 端口的请求转发到 6443 端口 （3 master 的 kube-apiserver 对外端口）
/etc/haproxy/haproxy.cfg
| | global |
| --- | --- |
| | log /dev/log local0 warning |
| | chroot /var/lib/haproxy |
| | pidfile /var/run/haproxy.pid |
| | maxconn 4000 |
| | user haproxy |
| | group haproxy |
| | daemon |
| | |
| | stats socket /var/lib/haproxy/stats |
| | |
| | defaults |
| | log global |
| | option httplog |
| | option dontlognull |
| | timeout connect 5000 |
| | timeout client 50000 |
| | timeout server 50000 |
| | |
| | frontend kube-apiserver |
| | bind *:16443 |
| | mode tcp |
| | option tcplog |
| | default_backend kube-apiserver |
| | |
| | backend kube-apiserver |
| | mode tcp |
| | option tcp-check |
| | balance roundrobin |
| | default-server inter 10s downinter 5s rise 2 fall 2 slowstart 60s maxconn 250 maxqueue 256 weight 100 |
| | server kube-apiserver-1 192.168.31.203:6443 check |
| | server kube-apiserver-2 192.168.31.34:6443 check |
| | server kube-apiserver-3 192.168.31.46:6443 check |
安装 kubernetes 集群
master1
| | kubeadm init --image-repository registry.aliyuncs.com/google_containers --control-plane-endpoint=192.168.31.230:16443 --v=10 |
| --- | --- |
master2 和 master3 加入集群
| | kubeadm join 192.168.31.230:16443 --token rxblci.ddh60vl370wjgtn7 --discovery-token-ca-cert-hash sha256:d712016d5b8ba4ae5c4a1bda8b6ab1944c13a04757d2c488dd0aefcfd1af0157 --certificate-key c398d693c6ce9b664634c9b670f013da3010580c00bd444caf7d0a5a81e803f5 --control-plane --v=10 |
| --- | --- |
worker 加入集群
| | kubeadm join 192.168.31.230:16443 --token rxblci.ddh60vl370wjgtn7 \ |
| --- | --- |
| | --discovery-token-ca-cert-hash sha256:d712016d5b8ba4ae5c4a1bda8b6ab1944c13a04757d2c488dd0aefcfd1af0157 |
查看集群状态
| | kubectl get node |
| --- | --- |
| | NAME STATUS ROLES AGE VERSION |
| | master1 Ready control-plane 21m v1.28.2 |
| | master2 Ready control-plane 3m46s v1.28.12 |
| | master3 Ready control-plane 2m12s v1.28.12 |
| | worker1 Ready 5s v1.28.2 |
测试
| | # 关闭 master1 的 kubelet 和 apiserver |
| --- | --- |
| | systemctl stop kubelet |
| | sudo kill -9 $(pgrep kube-apiserver) |
| | |
| | kubectl get node |
| | NAME STATUS ROLES AGE VERSION |
| | master1 NotReady control-plane 25m v1.28.2 |
| | master2 Ready control-plane 7m40s v1.28.12 |
| | master3 Ready control-plane 6m6s v1.28.12 |
| | worker1 Ready 3m59s v1.28.2 |
| | |
| | |
| | # 关闭 master1 的 haproxy |
| | systemctl stop haproxy |
| | root@master1:/home/zhy# kubectl get node |
| | NAME STATUS ROLES AGE VERSION |
| | master1 NotReady control-plane 26m v1.28.2 |
| | master2 Ready control-plane 9m12s v1.28.12 |
| | master3 Ready control-plane 7m38s v1.28.12 |
| | worker1 Ready 5m31s v1.28.2 |
| | |
| | # 关闭 master2 的 keepalived |
| | kubectl get node |
| | NAME STATUS ROLES AGE VERSION |
| | master1 NotReady control-plane 28m v1.28.2 |
| | master2 Ready control-plane 10m v1.28.12 |
| | master3 Ready control-plane 9m12s v1.28.12 |
| | worker1 Ready 7m5s v1.28.2 |
| | |
| | # 可以看到 虚拟ip 跑到了 master3 上 |
| | ip a show enp0s3 |
| | 2: enp0s3: mtu 1500 qdisc fq_codel state UP group default qlen 1000 |
| | link/ether 08:00:27:f1:b5:ae brd ff:ff:ff:ff:ff:ff |
| | inet 192.168.31.46/24 metric 100 brd 192.168.31.255 scope global dynamic enp0s3 |
| | valid_lft 41021sec preferred_lft 41021sec |
| | inet 192.168.31.230/32 scope global enp0s3 |
| | valid_lft forever preferred_lft forever |
| | inet6 fe80::a00:27ff:fef1:b5ae/64 scope link |
| | valid_lft forever preferred_lft forever |