VIDM loses DNS settings after applying patch

Products

• VCF Operations/Automation (formerly VMware Aria Suite)

Issue/Introduction

• Applied patch CSP-102092 as per KB CSP-102092 Patch Instructions for VMware Identity Manager 3.3.7 , after the reboot of the appliance DNS settings are lost in /etc/resolv.conf 
• Applying the steps in the KB VIDM DNS changes after restart temporarily resolve this, but after a reboot the DNS settings are lost again
• The KB DNS settings are not being imported from vCenter after upgrading Identity Manager does not resolve the issue
• Running the command systemctl status systemd-resolved in VIDM root ssh session shows that the systemd-resolved.service is disabled 

  systemd-resolved.service - Network Name Resolution
  Loaded: loaded (/usr/lib/systemd/system/systemd-resolved.service; disabled; vendor preset: enabled)

Environment

VIDM 3.3.x

Resolution

1. Take snapshot of all VIDM nodes in the cluster , please do not move forward until you have snapshots taken
2. Run the command :
   • sudo systemctl enable systemd-resolved.service
   • sudo systemctl start systemd-resolved.service
3. Repeat step 2 for each VIDM node in the cluster 
4. Reboot the cluster as per KB Graceful Shutdown and Power On of a VMware Identity Manager PostgreSQL cluster 
5. Confirm if DNS settings remain in /etc/resolv.conf 

Additional Information

Network not found error or networking information gets reset to old entries after upgrading VMware Identity Manager or after applying patch