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Dana_Knudson_24's avatar
Dana_Knudson_24
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Jan 29, 2016

Floating IP the same on HA pair?

I am setting up a pair of BIG-IP VE in my lab and following a HA lab guide from F5.

 

The configuration has me setting different floating IPs for each BIG IP.

 

BIG-IP_1

 

Internal Self IP 10.128.20.240/24 Floating IP 10.128.20.242

 

External Self IP 10.128.10.240/24 Floating IP 10.128.10.242

 

BIG-IP_2

 

Internal Self IP 10.128.20.241/24 Floating IP 10.128.20.243

 

External Self IP 10.128.10.241/24 Floating IP 10.128.10.243

 

The load balanced web page comes up fine with either BIG-IP_1 or BIG-IP_2 as Active.

 

My understanding is that the floating IP should be the same on each BIG-IP. However, when I try to give the Floating IP the same address on both BIG-IPs the web page will only display on BIG-IP_1 and times out if BIG-IP_2 is Active.

 

I am confused by this behavior. Can someone explain?

 

6 Replies

  • A floating self-IP follows the traffic-group that contains it. A traffic-group can only be active on a single member of a device-group at any given time.

     

    Normal configuration would be that the floating is the same on all units in the same device-group. The fact that you're able to configure them differently means that the two devices are not in sync with each other.

     

    In addition to any non-floating IP addresses, the active device will respond to requests for any floating IP, and any virtual address (the destination field in a virtual sever) in a traffic-group that it is active for.

     

    When a failover event occurs, the newly active device sends out gratuitous arps for the IP addresses that it now owns. It is possible that those garps are being quietly ignored by your network - if this is the case, then clearing the ARP entry on the router (or client, if you're on the same subnet) would resolve that.

     

    BigIP also offers the ability to use a single MAC address for the traffic-group, to work around this sort of problem. You can configure that feature under Device Management / Traffic Groups / . Using MAC masquerade means that not only does the IP address float to the active device, but it takes the MAC address with it.

     

  • Hi Ian,

     

    How can we make standby device of our own choice as Active..??

     

    We have 6 devices in cluster and 2 are for our DR purpose.

     

    Recently we tested the manual failover process by doing force offline on Next active device as we wanted to make standby device of our own choice as Active.

     

    After this step, The device which we wanted to make as active device, came up as Next Active device.

     

    So went into the current active device and forced it offline via the “run /sys failover offline” command.

     

    We were now waiting for device of our own choice to become active, however it did NOT come to active status and under “Current Active Device” it showed unassigned.

     

    We are currently running on 11.4.1 HF9. Did we followed correct process, If yes then Are we hitting any bug?

     

    Any help on this would be much appreciated.

     

    Regards, Mahantesh.

     

  • Failover should occur in the order defined under device-management / traffic-groups / traffic-group- / Failover Order.

     

    Note that the device-group must be in sync for this to work - if you've just changed the order, and not performed a sync (and auto-sync is not enabled), then the next active device shown on the traffic-group will not necessarily reflect the order specified in the failover order.

     

    If the order is configured so that the current device is not allowed, a failover will not be triggered - you will need to do that manually by forcing the active device to standby (or offline, which is a bit overkill)

     

  • Hi Ian,

     

    You mean to say we will not be able to choose next active device of our own choice by changing the failover order under each traffic group..?

     

    currently auto sync feature is enabled on our F5.

     

    Regards, Mahantesh

     

    • IanB's avatar
      IanB
      Icon for Employee rankEmployee
      I said the opposite. Failover should occur in the order you define for the traffic-group. If that's not what you're seeing, then you should open a support case with F5 to investigate the problem.
  • Hi,

     

    This is happening to me as well, I have configured the same Floating IP Address [internal] for both VE F5s before joining them as HA pair, and the behaviour is a bit weird as sometimes, depending on which one is Active and which one is Standby, it loads the page from the Webserver and sometimes it gives me time-out.

     

    I am thinking in building them up again using different Floating IP Addresses and then join them as HA.

     

    Have you manage to resolve that issue? Any suggestion on the new implementation I am going to go through again.