A lightweight LVS baby care, support ipvs health check
If ipvs real server is unavilible, remove it, if real server return to normal, add it back. This is useful for kubernetes master HA.
lvscare care --run-once --vs 10.103.97.12:6443 --rs 192.168.0.2:6443 --rs 192.168.0.3:6443 --rs 192.168.0.4:6443
Then kubeadm join can use 10.103.97.12:6443 instead real masters.
Run lvscare as a static pod on every kubernetes node.
lvscare care --vs 10.103.97.12:80 --rs 192.168.0.2:6443 --rs 192.168.0.3:6443 --rs 192.168.0.4:6443 --interval 5
- -t every 5s check the real server port
- --health-port "6443" if not return 200 OK, remove the realserver
- --health-path "/healthz" if not return 200 OK, remove the realserver
If the realserver is on the same host, you need bind vip on a interface
ip link add sealyun-ipvs0 type dummy
ip addr add 10.103.97.12/32 dev sealyun-ipvs0
Clean your environment:
ip link del dev sealyun-ipvs
ipvsadm -C
start some nginx as realserver
docker run -p 8081:80 --name nginx1 -d nginx
docker run -p 8082:80 --name nginx2 -d nginx
docker run -p 8083:80 --name nginx3 -d nginx
lvscare care --vs 10.103.97.12:6443 --rs 127.0.0.1:8081 --rs 127.0.0.1:8082 --rs 127.0.0.1:8083 \
--health-path / --health-schem http
check ipvs rules:
ipvsadm -Ln
[root@iZj6c9fiza9orwscdhate4Z ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 10.103.97.12:6443 rr
-> 127.0.0.1:8081 Masq 1 0 0
-> 127.0.0.1:8082 Masq 1 0 0
-> 127.0.0.1:8083 Masq 1 0 0
As you can see, all the real server added. You can curl vip:
[root@iZj6c9fiza9orwscdhate4Z ~]# curl 10.103.97.12:6443
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
delete a nginx
[root@iZj6c9fiza9orwscdhate4Z ~]# docker stop nginx1
nginx1
[root@iZj6c9fiza9orwscdhate4Z ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 10.103.97.12:6443 rr
-> 127.0.0.1:8082 Masq 1 0 0
-> 127.0.0.1:8083 Masq 1 0 1
delete one more:
[root@iZj6c9fiza9orwscdhate4Z ~]# docker stop nginx2
nginx2
[root@iZj6c9fiza9orwscdhate4Z ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 10.103.97.12:6443 rr
-> 127.0.0.1:8083 Masq 1 0 0
your vip still accessable:
[root@iZj6c9fiza9orwscdhate4Z ~]# curl 10.103.97.12:6443
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
delete all the real server:
[root@iZj6c9fiza9orwscdhate4Z ~]# docker stop nginx3
nginx3
[root@iZj6c9fiza9orwscdhate4Z ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 10.103.97.12:6443 rr
[root@iZj6c9fiza9orwscdhate4Z ~]# curl 10.103.97.12:6443
curl: (7) Failed connect to 10.103.97.12:6443; 拒绝连接
all ipvs destination removed
Add then back:
[root@iZj6c9fiza9orwscdhate4Z ~]# docker start nginx1 nginx2 nginx3
nginx1
nginx2
nginx3
[root@iZj6c9fiza9orwscdhate4Z ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 10.103.97.12:6443 rr
-> 127.0.0.1:8081 Masq 1 0 0
-> 127.0.0.1:8082 Masq 1 0 0
-> 127.0.0.1:8083 Masq 1 0 0
Welcom back!