HAProxy 에서 Session 공유하기

HAProxy를 이용해서 Load Balancing을 할 때 설정파일에 다음과 같이 추가한다.

물론 사용 언어의 세션 아이디 값에 따라 다르다. 타임아웃은 밀리 세컨드 (1/1000 초)이며 request-learn으로 설정하면 

appsession PHPSESSID len 100 timeout 3600000 request-learn mode query-string

메뉴얼 참조...

appsession <cookie> len <length> timeout <holdtime>
           [request-learn] [prefix] [mode <path-parameters|query-string>]
  Define session stickiness on an existing application cookie.
  May be used in sections :   defaults | frontend | listen | backend
                                 no    |    no    |   yes  |   yes
  Arguments :
    <cookie>   this is the name of the cookie used by the application and which
               HAProxy will have to learn for each new session.

    <length>   this is the max number of characters that will be memorized and
               checked in each cookie value.

    <holdtime> this is the time after which the cookie will be removed from
               memory if unused. If no unit is specified, this time is in
               milliseconds.

    request-learn
               If this option is specified, then haproxy will be able to learn
               the cookie found in the request in case the server does not
               specify any in response. This is typically what happens with
               PHPSESSID cookies, or when haproxy's session expires before
               the application's session and the correct server is selected.
               It is recommended to specify this option to improve reliability.

    prefix     When this option is specified, haproxy will match on the cookie
               prefix (or URL parameter prefix). The appsession value is the
               data following this prefix.

               Example :
               appsession ASPSESSIONID len 64 timeout 3h prefix

               This will match the cookie ASPSESSIONIDXXXX=XXXXX,
               the appsession value will be XXXX=XXXXX.

    mode       This option allows to change the URL parser mode.
               2 modes are currently supported :
               - path-parameters :
                 The parser looks for the appsession in the path parameters
                 part (each parameter is separated by a semi-colon), which is
                 convenient for JSESSIONID for example.
                 This is the default mode if the option is not set.
               - query-string :
                 In this mode, the parser will look for the appsession in the
                 query string.

  When an application cookie is defined in a backend, HAProxy will check when
  the server sets such a cookie, and will store its value in a table, and
  associate it with the server's identifier. Up to <length> characters from
  the value will be retained. On each connection, haproxy will look for this
  cookie both in the "Cookie:" headers, and as a URL parameter (depending on
  the mode used). If a known value is found, the client will be directed to the
  server associated with this value. Otherwise, the load balancing algorithm is
  applied. Cookies are automatically removed from memory when they have been
  unused for a duration longer than <holdtime>.

  The definition of an application cookie is limited to one per backend.

  Note : Consider not using this feature in multi-process mode (nbproc > 1)
         unless you know what you do : memory is not shared between the
         processes, which can result in random behaviours.

  Example :
        appsession JSESSIONID len 52 timeout 3h

  See also : "cookie", "capture cookie", "balance", "stick", "stick-table",
             "ignore-persist", "nbproc" and "bind-process".