To achieve persistence, we will insert cookies in all connections coming from new clients. We will layer-4 load-balance the connections, and at the same time insert a cookie.
The cookie value will contain the server-id to which the connection was load-balanced. Next time when the same client connects, it will present the cookie. Using the cookie value, we will know which real-server to choose and send the connection to it.
ATTENTION: This requires SSL offload - ensure you are using at least ADX OS >= 12.1.
We will use Layer-7 switching using csw to achieve this. There are three important points to note:
Connections from new clients will not have the cookie. Thus, the ServerIron will not know how to switch those. To handle such clients, the ServerIron will send them to a pre-defined group. We need group-id to be assigned to each real-server.
However, once a server is selected, its ServerID will be used as the cookie value. We need server-id,to be used in the cookie value, assigned to each real-server.
For new connections, ServerIron will set a cookie. But we need to define this cookie name so that a set-cookie: CookieName=value can be sent by the ServerIron to the client. We need to define cookie-name under vip.