We use HAProxy with Keepalived to loadbalance traffic and kubernetes master nodes.
Upon a restart of one backend server (one master) TCP connection is closed to fronted on all remaining nodes (other masters & worker nodes).
While I could expect it for a subset of nodes i.e. part of frontend TCP connections are closed because connectivity to one backend server is down (well technically it probably times out because reboot is ungraceful), I wouldn’t expect it for all nodes. It just looks that ALL frontend TCP connections are closed while just SINGLE backend server goes down. Is that correct behaviour or is there some misconfiguration ?
Config is as below:
defaults log global mode http option httplog option dontlognull timeout connect 5000 timeout client 50000 timeout server 50000 frontend frontend-api bind <backend_ip>:7443 bind <frontend_ip>:6443 bind 127.0.0.1:7443 mode tcp option tcplog timeout client 300000 default_backend backend-api backend backend-api mode tcp option tcplog option tcp-check timeout server 300000 balance roundrobin default-server inter 10s downinter 5s rise 2 fall 2 slowstart 60s maxconn 250 maxqueue 256 weight 100 server master1 <backend_api_ip_srv1>:6443 check server master2 <backend_api_ip_srv2>:6443 check server master3 <backend_api_ip_srv3>:6443 check