You created a route using --tags no-ip to point 0.0.0.0/0 to a VM NAT gateway. What command makes existing instances use that tagged route?

To make existing instances use a route that is associated with a specific tag, you must apply that tag to the instances. The gcloud compute instances add-tags command is used to add new tags to existing virtual machine instances. By adding the no-ip tag to your instances, they will then match the route's tag and direct their 0.0.0.0/0 traffic to the specified NAT gateway. sudo sysctl -w net.ipv4.ipforward=1 enables IP forwarding on a Linux instance, which is necessary for a NAT gateway VM to forward traffic, but it doesn't assign tags to client instances. gcloud builds submit is for Cloud Build, unrelated to VM instance tags. gcloud compute instances create is for creating new instances, not modifying existing ones.