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TJ_Vreugdenhil's avatar
TJ_Vreugdenhil
Icon for Cirrus rankCirrus
Jun 26, 2017

HTTP Redirect persistence logic

Hello!

 

1) The client comes into the first VIP (SSL offload) and picks a MEM-ID server. Let's say MEM-ID-SRV01. It then talks to Service-SRV-01. The client wants all future connections to stay in the same color servers. (The connections to the back end service srv's are a direct connection (not through the LB).

 

2) MEM-ID-SRV01 will send a redirect back to the client to go to the other VIP(SSL offload). But the requirement is that the request will go to OLB-SRV-01 in this case.

 

Is it best to have the MEM-ID-SRV01 send a specific header or append a unique HTTP path to the redirect back to the client? Then have the 2nd VIP have irule logic to send it to the specific server, or is there a way to create a hash value on the F5 during the initial LB selection and make sure that hash value gets appended to the MEM-ID-SRV redirect back to the client. (This 2nd option would prevent work done on the MEM-ID Servers)

 

Thanks!

 

 

application delivery
hash
header
iRules
LTM
two vip&39s

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  • TJ_Vreugdenhil's avatar
    TJ_Vreugdenhil
    Icon for Cirrus rankCirrus
    Jun 27, 2017

    Here is what I ended up with if it helps anyone else: 

    v11.6.0

when CLIENT_ACCEPTED {
set retries 0
}
when LB_FAILED {
 set number of desired retries to selected node below
if { $retries < 1 } {
  persist none
  LB::mode rr
  LB::reselect pool A-TS-OLB-DMZ-443-POOL
  incr retries
  }
  log local0. "Sending HTTP query [HTTP::query] to node [LB::server]"
}
when HTTP_REQUEST {
   switch -glob [string tolower [HTTP::query]] {
    "memid=1" { node 192.168.112.141 }
    "memid=2" { node 192.168.112.142 }
    "memid=3" { node 192.168.112.143 }
    "memid=4" { node 192.168.112.144 }
    "memid=5" { node 192.168.112.145 }
    default { pool A-TS-OLB-DMZ-443-POOL }
  }
  log local0. "Sending HTTP query [HTTP::query] to node [LB::server addr]"
}