vCenter 6.7 Update 3 HA with DDNS – Disable DDNS on vCenter

As it stands today (11/11/2019), vCenter 6.7U3 has been released with a new DDNS “feature” that seems to be creating an issue when leveraging vCenter HA. The issue is that when vCenter updates DNS, it sends both the management IP and the HA IP. The HA IP should really never be seen by the end user. Since both IPs are updated in DNS via DDNS, you get a round-robin situation for the name that you have allocated to your vCenter appliance.

This will take you through updating vCenter so it doesn’t do DDNS and hence does not create two DNS entries for your vCenter server. Having said that, you will have to create a static DNS entry for your vCenter server (which is the normal operation when deploying vCenter anyway).

Please see the Release Notes to read more on the DDNS feature.

Disable DDNS on vCenter

  1. We are going to need to SSH into your vCenter server. 
  2. Type the following to remove the cron job. Feel free to back the file up.

    cd /etc/cron.d/

    rm -f dns_update.cron

  3. We now have to deal with a python script that runs. Type the following:

    ps -eaf | grep ddns

  4. This will give you a PID for the following:



  5. For this example, we are grabbing the 4431 PID and executing the following:

    kill -9 4431

  6. Let’s validate that we have killed it.

    ps -eaf | grep ddns

  7. Just make sure the ddns.py script isn’t running.
  8. Now we need to do an edit.

    cd /usr/lib/applmgmt/support/scripts/

    vi prestart-applmgmt.sh

  9. Since you are in vi, lets hit the / key and type: DDNS
  10. You will find the following lines that you need to comment out. Please see the below snippet of what needs to be commented:



  11. Note that we’ve added a # in front of each of the lines we no longer want to run. Now hit ESC and type:

    :wq!

  12. Once you hit ENTER the file will be saved and you’ll return to a command prompt.
  13. Now we need to restart a service:

    service-control –stop applmgmt

    service-control –start applmgmt

  14. vCenter should no longer update DNS.

2 Replies to “vCenter 6.7 Update 3 HA with DDNS – Disable DDNS on vCenter”

    • Thanks. I haven’t tested U3b but I did figure VMware would address the issue (which is why I was so specific in my post title to the specific version). I know when I tested U3a, it was not fixed. 🙂

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