How to use Haproxy redis-check with a password
It seems like
option redis-check in Haproxy does not support Redis-databases that requires authentication as of 1.9.6 (newest version).
That means that if you want to check the health of password protected redis-servers, you would have to use a
tcp-check, so you will have to modify your check like this:
listen redisserver bind *:6380 mode tcp server redis_backend someredisserver:11020 option redis-check
listen redisserver bind *:6380 mode tcp server redis_backend someredisserver:11020 option tcp-check tcp-check send AUTH\ aveeeeeryseeeecretpassword\r\n tcp-check expect string +OK tcp-check send PING\r\n tcp-check expect string +PONG