Tor relay/exit nodes under preemptible VMs

Running multiple preemptible nodes for redundancy is a bad plan. If the preemptible nodes are running in the same region they are quite likely to be shut down simultaneously due to increasing demand in the region.

Preemptible nodes in different regions are less likely to be shut down simultaneously, but the risk still exists and can depend on what other GCE customers are doing, which is entirely outside your control.

Don't use preemptible nodes if you care about availability. They are suitable for batch processing where being preempted isn't much of a problem and you can just do the processing at a later time.

Is safe to run preemptible nodes that shuts down at 24 hours of running or less? (IP address assignment are dynamic and the same IP for a new node is not guarranteed)

Safe? Sure. But you'll never see any traffic to them. There is an excellent writeup on the way Tor vets new relays and exit nodes here: The lifecycle of a new relay

Essentially any new relay is "tested out" for 60+ days before it sees any real traffic. I can vouch that this is accurate as I've been running a Tor relay for about 2 years. You're unlikely to see any real traffic unless your nodes keep the same IDs each time they are restarted, and if your node cannot prove to be reliable it will likely be placed lower down in the food chain.

Additionally if the node goes offline for a long time, you may have to re-sit those waiting periods. My relay was offline for 3 months as I moved countries and I'm yet to see traffic return to what it used to be.

You can see what Tor believes about your relay by looking it up on their metrics page. For example, here is mine.

Are the g1-small VM specs enough to run a high performance node?

Tor's idea of high performance is different to the general internet at large. For example I am running mine on a pretty old Intel NUC with a pretty old Intel Celeron processor and a sad amount of RAM and it caps out at about 70Mbps - because that's all that OpenSSL can push through the CPU. 70Mbps is very large for a Tor relay (maybe not an exit node). I'd imagine even a basic semi-modern small VM would be able to outpace it.