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Kent_Saunders's avatar
Kent_Saunders
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Jan 20, 2021

BigIP DNS failover

We have BigIP DNS servers in 2 AWS regions. The DNS zones are synchronized using iQuery and both DNS servers are registered with the domain. In the event of a failure in the primary region we would like to automatically change an A record to resolve to the DR region. Is it possible to create an iRule that is triggered with a DNS lookup request (for a specific host name) that will then check the bigip health monitor and will respond with the DR IP if the primary DNS is offline? I have not been able to find a command to check the health monitor so I though I would ask here. Using a 3rd party service for DNS is not an option. We are also using DNSSEC.

 

Thanks

BIG-IP DNS
cloud
iRules
  • KeesvandenBos's avatar
    KeesvandenBos
    Jan 20, 2021

    Ok, you have to create two wide ip pools. One primairy with the virtual server of the primairy site, one with the DR site virtual server.

    Then in the wide ip select both pools with the primairy site at the top, for load balancing use Global availability.

    The DNS will return the primairy virtual server, the moment it becomes unavailable the DR virtual server will be returned on a query.

     

    Cheers,

     

    Kees

  • KeesvandenBos's avatar
    KeesvandenBos
    Icon for MVP rankMVP
    Jan 20, 2021

    Hi,

     

    Is this a full region failover or only a failure of the primary BIGIP DNS?

    And under normal circumstances is your DR region up and running?

     

    Cheers,

     

    Kees

  • Kent_Saunders's avatar
    Kent_Saunders
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    Jan 20, 2021

    It would be a for failure of the primary BIGIP. In addition to DNS, it is also running ASM for the web application. If DNS is not available/running on the primary, resolution will still occur - using the DNS server in the other region but we need the record automatically updated if the BIGIP/ASM in the primary site is offline.

     

    Thanks

  • KeesvandenBos's avatar
    KeesvandenBos
    Icon for MVP rankMVP
    Jan 20, 2021

    Ok, you have to create two wide ip pools. One primairy with the virtual server of the primairy site, one with the DR site virtual server.

    Then in the wide ip select both pools with the primairy site at the top, for load balancing use Global availability.

    The DNS will return the primairy virtual server, the moment it becomes unavailable the DR virtual server will be returned on a query.

     

    Cheers,

     

    Kees

  • Kent_Saunders's avatar
    Kent_Saunders
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    Jan 20, 2021

    I started to configure as suggested and I don't think this will work. The DNS zones on both servers are sync'd. Correct me if I am wrong but using a Wide IP with the 2 pools will only ensure that the primary responds to DNS requests first. If the primary is not available, the secondary will respond. The problem is the secondary has the same records. We need need the website's A record to be changed to the DR site.

     

    Thanks

  • KeesvandenBos's avatar
    KeesvandenBos
    Icon for MVP rankMVP
    Jan 21, 2021

    Hi Kent,

     

    Both wide IP pools should contain only 1 ip/record

    The primairy the IP/record of the primairy site. The secondary the IP/record of the DR site.

     

    Cheers,

     

    Kees