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sand87ch's avatar
sand87ch
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Nov 16, 2022

Handling sideband server failure

Hi, In my setup i have a BIGIP virtual server in front of a pool,This bigip VIP has a sideband connectiont o a virtual server that mirrors the requests and respobnses into my bigip VIP server. \Iss...
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sand87ch's avatar
sand87ch
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Hi Kevin,

Our set up has a BigIP F5 that is connected to a customer website in a pool.The client places a request to the wesite via this BIG IP LTM and receives a response.We have irules that connect to the helper VS that to mirror the request and response

We also have a helper VS in the environment.We use this Helper VS to establish a sideband connection to our pool which receives the mirrored request and response to the main BIG IP load balancer.

 

However if the server in our pool goes down then for a small amount of time the requests coming to the customer website via teh BIG IP load balancer is getting interrupted where the client receives a "connection reset " error.This is resullting in stability issue.

 

Is there any way to isolate the connection so that any failure on our pool doesnt cause a connection reset error on the client website?

 

Kevin_Stewart's avatar
Kevin_Stewart
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Nov 17, 2022

Hard to say without a better understanding of your config and current iRule.

  • sand87ch's avatar
    sand87ch
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    Nov 21, 2022

    Hi Kevin,

    I think i could fix my issue if i can get some help with the following info.

    1.How to check if the helper virtual server(not the load balancer virtual server) is down or offline?

    2.How to check if the whole pool is down/offline and not just the members.

    I have seen certain commands but they specify LB::Status which is the staus of the Load balancer virtual server which is not helping me.

    I checked a lot but either its not mentioned anywhere or i may have missed it.

    Any idea?

     

     

    • Kevin_Stewart's avatar
      Kevin_Stewart
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      Nov 21, 2022

      A few options maybe.

      1. Do you have a monitor assigned to the pool? A failed pool should automatically flag the VIP as offline. You may also consider setting the pool's "Action On Service Down" option to Reject.

      2. Use the 'active_members' condition in an iRule:

      when CLIENT_ACCEPTED {
  if { [active_members sideband_pool] < 1 } {
    reject
  }
}
      • sand87ch's avatar
        sand87ch
        Icon for Cirrus rankCirrus
        Nov 22, 2022

        Hi Kevin,

        Please find my answers to your question sbelow:-

        1. Do you have a monitor assigned to the pool? A failed pool should automatically flag the VIP as offline. You may also consider setting the pool's "Action On Service Down" option to Reject.

        Yes.However our pool has an ec2 node that stays green even when the service is down as seen in the below image.Hence the member check fails.

        Which brings me to your next question

        2. Use the 'active_members' condition in an iRule:

        I already have this rule enabled but this fails due to the above mentioned issue.

        Not only this, the problem is that i need to handle the send command error so that the moment any TCP error happens while the traffic is mirrored from the LB to the external mirror pool, the exception is thrown and the execution stops thereby  allowing the traffic to move to the client website

        when HTTP_RESPONSE{

        set send_data [send -timeout $connectionTimeout -status send_status $conn_id $responseData]

        close conn_id ;

        }