VMWare vCenter Server Heartbeat - How to Use the DNSConfTool Utility

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Summary

This knowledge base article describes how to use the DNSConfTool utility. DNSConfTool was included for use of the multi-identity feature of vCenter Server Heartbeat 6.3 Update 1 to construct and execute the command line(s) to be passed to DNSUpdate.exe based on multi-identity configuration in a LAN (public service name, machine names, public and management IPs).


More Information

vCenter Server Heartbeat v6.3 U1 Multi-ID

vCenter Server Heartbeat in multi-identity when deployed in a LAN, incorporates the concept of three names:

  • Public Service Name - the name vCenter clients connected to prior to installing vCenter Server Heartbeat
  • Primary Machine Name - the machine name of the primary node, used as a management name when passive
  • Secondary Machine Name - the machine name of the secondary node, used as a management name when passive

After installation, clients continue to connect to vCenter Server through DNS via the Public Service Name, while management applications connect to the passive server through DNS via the machine name. Each name is associated with a different IP address in DNS forward and reverse zones. As a result of switchover, the public IP is added to the server that is active while its management IP is removed resulting in the active server having the public IP, which is associated with the public service name in DNS, while the passive server has its management IP that is associated with its machine name via DNS.

DNS Entries: LAN Multi-ID Mode

  • P(+) -> S(-)
    • P(+)
      • Public Service Name -> Public IP
      • Primary Machine Name -> Nothing
    • S(-)
      • Secondary Machine Name -> Secondary Management IP
    • Dnsconftool.exe generated the following the commands for DNSUpdate.exe:
      • Add Public Service Name -> Public IP
      • Remove Primary Machine Name -> Primary Management IP
      • Add Secondary Machine Name -> Secondary Management IP
  • S(+) -> P(-)
    • P(-)
      • Primary Machine Name -> Primary Management IP
    • S(+)
      • Public Service Name -> Public IP
      • Secondary Machine Name -> Nothing
    • Dnsconftool.exe generated the following commands for DNSUpdate.exe
      • Add Public Service Name -> Public IP
      • Add Primary Machine Name -> Primary Management IP
      • Remove Secondary Machine Name -> Secondary Management IP

In addition to generating the DNS commands, dnsconftool.exe also uses nslookup to check DNS to prevent adding unnecessary entries via DNSUpate.exe thereby reducing the time necessary to complete the process. After the DNSUpdate.exe commands have been issued, dnsconftool.exe uses nslookup to verify that DNS entries are as expected and reports back if they are not.

DNSConfTool exit / error codes are as follows:

  • SUCCESS(0) : dnsconftool.exe executed successfully with no errors
  • INCORRECT_USAGE(1) : no parameters were provided to dnsconftool.exe
  • INVALID_PARAMETERS(2) : an invalid parameter was provided to dnsconftool.exe
  • FATAL_WINDOWS_ERROR(4) : an exception occurred when trying to execute a child process for example DNSUpdate.exe, this doesn't indicate an error from DNSUpdate.exe it's a failure encountered by Windows trying to initiate the process
  • MULTIID_NOT_ENABLED(103) : dnsconftool.exe has been executed in an installation where multi-identity has not been configured, no changes to DNS will be attempted
  • DNS_CHECK_FAILURE(104) : dnsconftool.exe has executed but the DNS entries are not configured as expected in DNS



vCenter Server Heartbeat v6.3 Update 1 LAN Multi-ID Preserve Passive IP Mode

vCenter Server Heartbeat v6.3 Update 1 incorporates a different DNS update mode of operation where management IP addresses remain on each of the machines (Primary and Secondary) and also remain associated with the machine names in DNS. Only the Public IP is moved from machine to machine during a switchover, this mode is referred to as the Preserve Passive IP mode.

DNS Entries : LAN Multi-ID Preserve Passive IP Mode

  • P(+) -> S(-)
    • P(+)
      • Public Service Name -> Public IP
      • Primary Machine Name -> Primary Management IP
    • S(-)
      • Secondary Machine Name -> Secondary Management IP
    • dnsconftool.exe generated the following commands for DNSUpdate.exe
      • Add Public Service Name -> Public IP
      • Add Primary Machine Name -> Primary Management IP
      • Add Secondary Machine Name -> Secondary Management IP
  • S(+) -> P(-)
    • P(-)
      • Primary Machine Name -> Primary Management IP
    • S(+)
      • Public Service Name -> Public IP
      • Secondary Machine Name -> Secondary Management IP
    • dnsconftool.exe generated the following commands for DNSUpdate.exe
      • Add Public Service Name -> Public IP
      • Add Primary Machine Name -> Primary Management IP
      • Add Secondary Machine Name -> Secondary Management IP


vCenter Server Heartbeat v6.3 Update 1 LAN Multi-ID No DNS updating

vCenter Server Heartbeat v6.3 Update 1 DNS updating removes the dnsconftool.exe. DNS updating is not performed. Installation Release Notes identified that customers must manually configure DNS with the following parameters:

DNS Entries:

  • Public Service Name -> Public IP
  • Primary Machine Name -> Primary Management IP
  • Secondary Machine Name -> Secondary Management IP

vCenter Server Heartbeat v6.4 WAN Multi-ID

vCenter Server Heartbeat 6.4 incorporates DNS updating for Multi-identity only when deployed in a WAN using Dnsconftool.exe. vCenter Server Heartbeat 6.4 deployed in a WAN is similar to the LAN Preserve Passive IP mode of vCenter Server Heartbeat 6.3 Update 1 except that different Primary / Secondary Public IPs are used.

DNS Entries : WAN Multi-ID Preserve Passive IP Mode

  • P(+) -> S(-)
    • P(+)
      • Public Service Name -> Primary Public IP
      • Primary Machine Name -> Primary Management IP
    • S(-)
      • Secondary Machine Name -> Secondary Management IP
    • dnsconftool.exe generated the following command for DNSUpdate.exe to:
      • Remove Public Service Name -> Secondary Public IP
      • Add Public Service Name -> Primary Public IP
      • Add Primary Machine Name -> Primary Management IP
      • Add Secondary Machine Name -> Secondary Management IP
  • S(+) -> P(+)
    • S(+)
      • Public Service Name -> Secondary Public IP
      • Secondary Machine Name -> Secondary Management IP
    • P(-)
      • Primary Machine Name -> Primary Management
    • dnsconftool.exe generated the following command for DNSUpdate.exe to:
      • Remove Public Service Name -> Primary Public IP
      • Add Public Service Name -> Secondary Public IP
      • Add Primary Machine Name -> Primary Management IP
      • Add Secondary Machine Name -> Secondary Management IP


vCenter Server Heartbeat 6.5

vCenter Server Heartbeat 6.5 uses dnsconftool.exe in a WAN but DNS is not updated in a LAN.

DNSConftool.exe Usage

The DNSConftool.exe tool has been tested and is only supported with the following flags:

  • -auto : in this mode dnsconftool.exe reads the nfprefs and automatically determines the command lines to provide to DNSUpdate.exe based on a combination of the values of the following preferences:
    • PublicIdentityMBean.PublicIdentityMode
    • PublicIdentityMBean.PreservePassiveIPs
    • PublicIdentityMBean.PublicAddresses
    • PublicIdentityMBean.PassiveAddresses
  • -d : debug flag dnsconftool.exe debug (not DNSUpdate.exe)
  • -raw <arg>: passes the argument to DNSUpdate.exe. The available arguments are as per Neverfail KB #389 ( VMware KB 1008449 )
    • For example to get debug from DNSUpdate.exe

      -raw –d
For example, to specify a name server to DNSUpdate.exe
-raw “-ns 192.168.0.20” see VMWare KB 2004370 for more details on the relevance of this

While there are a host of other flags that can be supplied (use –h flag to display them), they have not been tested and are not supported or recommended.


Applies To

vCenter Server Heartbeat, all versions


Related Information

VMware KB 1008449 - Using the VMware vCenter Server Heartbeat Utility DNSUpdate.exe (DNS)

Neverfail Knowledgebase article #389 - How to Use the DNSUpdate.exe (DNS)

KBID-2586

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