Expected Status or String

Change the expected HTTP success status

Use http-check expect to specify the HTTP status code indicating a healthy server. In the following example, the server must return a 200 OK response:

backend bk_myapp
   option httpchk
   http-check expect status 200
   server srv1 10.0.0.1:80 check
   server srv2 10.0.0.2:80 check

As an alternative to http-check expect status, where you specify one explicit status value, you can use rstatus to specify a regular expression to match multiple status codes. In the next example, the health check uses rstatus in conjunction with the negation operator (!) to consider all statuses as valid except for 5xx responses:

backend bk_myapp
   option httpchk
   http-check expect ! rstatus ^5
   default-server inter 3s fall 3 rise 2
   server srv1 10.0.0.1:80 check
   server srv2 10.0.0.2:80 check

Setting an expect string in HTTP and TCP checks

You can specify a string to search for in the body of an HTTP or TCP response.

To specify the string that you expect to see in the body, add the expect string directive to http-check or tcp-check.

In the next example, the response must contain the string "OK".

backend be_myapp
  option httpchk
  http-check expect string OK
  server srv1 10.0.0.1:80   check
  server srv2 10.0.0.2:8080 check

Use the expect rstring argument to specify a regular expression instead of an explicit string.

For the complete list of parameters that can be specified on the expect line, see http-check expect.