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Follow these steps to update DNS Relays running on virtual machines (VMs) when the VM image must be updated. 

The DNS Relay updates automatically when using the images provided in the DNSFilter dashboard: no manual action is required. However when the VM image needs upgrades the DNS Relay must be redeployed. 

These steps use Ubuntu OS as an example, but similar steps apply to any VM. 

✍️ When updating the underlying VM image, redeploy the DNS Relays using the latest image and configurations from the Relay Install section of the dashboard.

Recommended Upgrade Process

Follow these steps to ensure a smooth transition with minimal network disruption.

1. Review and record the IP configuration of each existing relay

2. Generate replacement images

   1. Create new relay images with distinct hostnames for clarity
   2. Assign new IPv4 addresses to avoid conflicts with existing relays

3. Deploy and test the new relays

   1. Set static IP addresses on new relays

   2. Confirm network connectivity using the DNS Relay Deployment Guide

4. Configure networks to route traffic through the new relays

5. Ensure all devices and networks are functioning correctly with the updated relays

   1. Running new and old relays concurrently allows testing before full migration

6. Decommission old relays

   1. Remove old relays from the network 

   2. Devices with static DNS entries must be updated before decommissioning old relays

Alternative Approach: Existing relay IPs can be reused, but migration must occur one relay at a time to prevent network conflicts. The method above provides greater flexibility and minimizes potential downtime.