SQL ALwaysOn Dependencies

  • Hi all,

    Im having a strange problem. I have 2 Availability Groups set up both of which are working. Except 1 is giving me DNS update errors, Both are setup exactly the same way. We do not use microsoft DNS, we use Infoblox.

    The error im getting is:

    Cluster network name resource '<group_name+listener_name>' failed registration of one or more associated DNS name(s) for the following reason:

    DNS operation refused.

    .

    Ensure that the network adapters associated with dependent IP address resources are configured with at least one accessible DNS server.

    By <group_name+listener_name> i mean for example if the availability group name is 'AG1' and the group listener is 'listener1 then the entry here will be "AG1_listener1"

    and:

    Cluster network name resource 'Cluster Name' failed registration of one or more associated DNS name(s) for the following reason:

    DNS operation refused.

    .

    Ensure that the network adapters associated with dependent IP address resources are configured with at least one accessible DNS server.

    Any ideas?

  • Ok spoke to my network guys and they have added an entry to the DNS servers to allow my SQL boxes IP range to update DNS but what is this dependency and what does it relate too?

  • The reason for this is because of what happens when a failover of a virtual name resource occurs under Windows Server Failover clusters.

    The virtual network name is unregistered in DNS and then the Virtual IP is unbound from the NIC on the current host. The virtual IP address is bound to the NIC on the new node and then the DNS entry is re registered.

    If you're using a Windows DNS server then the permissions required are automatically granted and it works seemlessly, if you use a 3rd party DNS server you have more overhead for zone replication and updates.

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • Thanks for replying Perry, i understand the process of failover but i dont understand the purpose of the dependancy called "AG1_listener1" I cant see anywhere where this is referenced except in failover cluster manager. Its not pingable, isnt referenced in SSMS etc so i wasnt sure why it was failing to updatte a DNS entry for this name as it doesnt exist in DNS.

    The issue is now resolved by allowing DNS updates from my SQL servers IP range but was just wanting to clear up this dependencies meaning.

  • what you're seeing there is just the AlwaysOn listener resource. In the same group\application you should have a Virtual IP and networkname, this network name will be registered in AD and DNS.

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • We ran into the same issue at work. I wrote a longer blog post about the solution here: https://dpattersondba.wordpress.com/2015/06/02/sql-ag-on-infoblox/

    The short version is if you are using InfoBlox, add the IP for each host server (not just the cluster object) to the Update ACL in Grid Control and then restart the Grid Control Service, changes to the ACL will have no effect until the Grid Control Service is restarted.

  • I am getting the error and I am using Windows DNS & AD. Any insights?

  • I had the same isssue. I realized "DHCP Client", "Network Location Awareness" and "Network List Service" services were stopped. After started all these services both of node, the error message stopped.

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