Keepalived logs "IPVS: No such file or directory" when activating a real server and it is not visible in ipvsadm output

Issue

• With a real server previously failed a healthcheck and has now had a successful one, Keepalived_healthcheckers logs "Adding service [IP]:PORT to VS [IP]:PORT". But sometimes this is immediately followed by a log entry "IPVS: No such file or directory" and the real server is not visible in any of the expected ipvsadm output.

• It may also be seen after this that upon a subsequent healthcheck failure, "Removing service [IP]:PORT to VS [IP]:PORT" log entry will be followed by an "IPVS: No such destination" entry.

  Feb  1 10:05:11 localhost Keepalived_healthcheckers[12345]: Misc check to [10.20.30.1] for [/usr/local/sbin/checker.sh 80 10.20.30.1] success.
  Feb  1 10:05:11 localhost Keepalived_healthcheckers[12345]: Adding service [10.20.30.1]:80 from VS [192.168.10.1]:80
  Feb  1 10:05:11 localhost Keepalived_healthcheckers[12345]: IPVS: No such file or directory
  
  Feb  1 11:35:41 localhost Keepalived_healthcheckers[12345]: Misc check to [10.20.30.1] for [/usr/local/sbin/checker.sh 80 10.20.30.1] failed.
  Feb  1 11:35:41 localhost Keepalived_healthcheckers[12345]: Removing service [10.20.30.1]:80 from VS [192.168.10.1]:80
  Feb  1 11:35:41 localhost Keepalived_healthcheckers[12345]: IPVS: No such destination