Irule for Load-Balancing Host Headers and Redirects

I'd probably use a data group to define what Hosts need to be HTTP vs. HTTPS.

HTTP VIP iRule:

when HTTP_REQUEST {
    if { [class match [string tolower [HTTP::host]] equals my_https_dg] } {
        HTTP::redirect "https://[HTTP::host][HTTP::uri]"
    } elseif { ( [HTTP::uri] equals "/" ) and ( [class match [string tolower [HTTP::host]] equals int_redirect_map] ) } {
        HTTP::redirect "http://[HTTP::host][class match -value [string tolower [HTTP::host]] equals int_redirect_map]"
    } elseif { [class match [string tolower [HTTP::host]] equals int_host_map] } {
        pool [class match -value [string tolower [HTTP::host]] equals int_host_map]
    } else {
        HTTP::respond 404 content "...data..."
    }
}

where "my_https_dg" is a string-based data group containing all of the host names that have to be HTTPS.

HTTPS VIP:

when HTTP_REQUEST {
    if { ( [HTTP::uri] equals "/" ) and ( [class match [string tolower [HTTP::host]] equals int_redirect_map] ) } {
        HTTP::redirect "https://[HTTP::host][class match -value [string tolower [HTTP::host]] equals int_redirect_map]"
    } elseif { [class match [string tolower [HTTP::host]] equals int_host_map] } {
        pool [class match -value [string tolower [HTTP::host]] equals int_host_map]
    } else {
        HTTP::respond 404 content "...data..."
    }
}