haproxy https health checks

Question

Hi I am using haproxy to load balance my https connections. I want to do active health checks however they don't seem to work. Any tips on how to correctly write the below would be welcome. I have them working fine for http port 80 connections.

frontend incoming_https
  bind *:443
  mode tcp
  default_backend web_https

backend web_https
    mode tcp
    option httpchk GET / HTTP/1.1\r\nHost:\ https://www.mysite.com
    server web-0 xxx.xxx.xxx.xxx:443 check inter 5000 port 443

Answer 1

Yes, you can use option httpchk in tcp mode. Here's the necessary options to search for a string on a page behind ssl:

mode tcp
option httpchk GET /<URI>
http-check expect string <STRING\ WITH\ SPACES\ ESCAPED>
server <YOUR_SERVER_FQDN>:443 <YOUR_SERVER_IP>:443 check ssl verify none

for example, to check a login.html page for "User Name" string:

mode tcp
option httpchk GET /login.html
http-check expect string User\ Name
server www.example.com:443 192.168.1.1:443 check ssl verify none

Note that "check ssl verify none" is required and that any spaces in your search string must be escaped with a \.

Answer 2

You can't use option httpchk in tcp mode.

You'll probably want to read up on option ssl-hello-chk.