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mpromny_136509's avatar
mpromny_136509
Icon for Nimbostratus rankNimbostratus
Dec 11, 2013

How LTM attaches information about node to JSessionsID ?

Hi all,

 

I'd like to ask whether you could explain me how LTM attaches information about node to JSessionsID used in cookie.

 

Introduction:

 

  • we have pool SRV_POOL: -SRV1 10.10.10.1 -SRV2 10.10.10.2 -SRV3 10.10.10.3 (new)

     

  • system creates cookies with JSessionID

     

ISSUE:

 

Recently we've added additional node to our pool. Issue occurs when request goes to last node and we get: C73AA9C0CC0F1045667015AF8F281AD4.node1 instead of node3

 

Logs:

 

Rule /Common/Node3Log : 10.7.255.251:16966: Used persistence record from cookie. Existing key? /Common/SRV_POOL 10.10.10.3 8080 Rule /Common/Node3Log : 10.7.255.251:16965: Request to .../soria/images/tooltipConnectorRight.gif with cookie: C73AA9C0CC0F1045667015AF8F281AD4.node1

 

Question:

 

Would you please explain me how LTM assignes nodes' information to JSession?

 

Thank you in advance, Mateusz

 

application delivery
deployment
devops
irule
iRules
jsessionid
node
  • Kevin_Stewart's avatar
    Kevin_Stewart
    Icon for Employee rankEmployee
    Dec 16, 2013

    If I may add:

     

    1. The universal persistence iRule (I'm assuming "PI_JSESSION_ID" in this case), should be applied to the universal persistence profile, not the VIP.

       

    2. You wouldn't have two persistence profiles then, either universal or cookie.

       

    3. If you can support cookies, and there's no specific technical reason to rely on the JSESSIONID from the server, I would recommend standard LTM Cookie persistence. You can change the name of the cookie if you need to, but it is easily the most reliable persistence method.

       

  • fpaj_137139's avatar
    fpaj_137139
    Icon for Nimbostratus rankNimbostratus
    Dec 16, 2013

    Hi, I'm working on this issue with Mateusz. It is standalone box, no HA cluster.

     

    fpaj

     

  • mpromny_136509's avatar
    mpromny_136509
    Icon for Nimbostratus rankNimbostratus
    Dec 16, 2013

    Hi Christian,

     

    We have universal and cookie because:

     

    iRULE - uie

     

    virtual - cookie

     

    Virtual server configuration:

     

    ltm virtual PI-SSL {

     

    destination 10.59.20.10:https

     

    fallback-persistence PI_Tomcat-src

     

    ip-protocol tcp

     

    mask 255.255.255.255

     

    persist {

     

    PI_COOKIE {

     

    default yes

     

    }

     

    }

     

    pool SRV_POOL

     

    profiles {

     

    PI-HTTPS-NEW.app/PI-HTTPS-NEW_http_profile { }

     

    PI-HTTPS-NEW.app/PI-HTTPS-NEW_lan-optimized_tcp_profile {

     

    context serverside

     

    }

     

    PI-HTTPS-NEW.app/PI-HTTPS-NEW_oneconnect { }

     

    PI-HTTPS-NEW.app/PI-HTTPS-NEW_wan-optimized_tcp_profile {

     

    context clientside

     

    }

     

    PI-requestLog { }

     

    PI_SSL {

     

    context clientside

     

    }

     

    analytics { }

     

    }

     

    rules {

     

    PI_X-Forward

     

    PI_JSESSION_ID

     

    }

     

    snat automap

     

    source-port change

     

    vlans-disabled

     

    }

     

    IRULE:

     

    when HTTP_REQUEST {

     

    if { [HTTP::cookie exists "JSESSIONID"] } {

     

    persist uie [HTTP::cookie "JSESSIONID"] 500

     

    } else {

     

    set jsess [findstr [HTTP::uri] "JSESSIONID" 11 ";"]

     

    if { $jsess != "" } {

     

    persist uie $jsess 500

     

    }

     

    }

     

    }

     

    when HTTP_RESPONSE {

     

    if { [HTTP::cookie exists "JSESSIONID"] } {

     

    persist add uie [HTTP::cookie "JSESSIONID"] 500

     

    }

     

    }

     

  • Christian_30338's avatar
    Christian_30338
    Historic F5 Account
    Dec 16, 2013

    Thanks. So looking at the output do you have a cookie persistence or a universal persistence profile enabled on the virtual server? Also do you have any iRules enabled influencing the persistence?

     

  • Christian_30338's avatar
    Christian_30338
    Historic F5 Account
    Dec 11, 2013

    Hello,

    I am not sure how you have persistence configured on the F5 but it sounds like the session persistence table needs to be investigated. Use something similar to the following command to check.

    tmsh show /ltm persistence persist-records all-properties

    If your server is generating cookies then then above command can help you to understand which cookie is being persisted to each server.

    What is the lifetime of your cookies that the server generates?

    Christian