GCP抢占式VM公网访问及配额问题咨询：是否需切换至AWS？

Hey there, let's break down your problem and fix it step by step—no need to jump to AWS just yet, since GCP's preemptible VMs are a great fit for your workload!

First: Correcting Your Cloud NAT Misunderstanding #

You mentioned GCP NAT feels like 1:1, but that's only if you've configured Static NAT mappings (used for external traffic to reach internal VMs). The default Cloud NAT setup is actually multi-to-one SNAT—meaning dozens of internal VMs can share a small pool of public IPs (even just 1!) to access external services like your Cloud Run API. This was likely a configuration misstep on your end.

Practical Solutions to Fix Your Quota & Access Problem #

1. Configure Default Cloud NAT for Multi-to-One Outbound Access #

This is the quickest fix to bypass the public IP quota limit:

• Deploy preemptible VMs without public IPs: When creating VMs, uncheck the "Assign public IP" option. They'll only have internal IPs in your VPC.
• Set up a Cloud NAT gateway: In your VPC dashboard, create a NAT gateway tied to the subnet where your VMs live. Leave "Static NAT mappings" blank (this is the key to avoiding 1:1).
• Verify routing: Ensure the subnet's outbound routes point to the NAT gateway. All VM traffic to your Cloud Run API will now route through the NAT's public IP(s), no individual VM public IP needed.

2. Use Serverless VPC Access for Private Cloud Run Access (Better Long-Term) #

If your Cloud Run API only needs to be accessed by your VMs, cut out the public internet entirely:

• Create a Serverless VPC Access Connector: This links your Cloud Run service to your VPC's private subnet.
• Update Cloud Run configuration: Associate the service with the connector, and set ingress to all (if you still need public access) or internal-only (if only VMs need access).
• Access Cloud Run privately: Your VMs can now reach the Cloud Run API using its internal DNS name or private IP, no public IPs required for either VMs or the API. This is more secure, lower latency, and completely avoids public IP quotas.

3. Bonus: Optimize Quota Usage (If Needed) #

• Check for unused public IPs: Make sure you're not holding onto unused static public IPs that eat into your quota.
• Shared VPC (Enterprise): If you're part of an organization, use Shared VPC to pool quota across multiple projects—this can help if you need more public IPs for other use cases.

Should You Switch to AWS? #

Absolutely not. Your workload is a perfect match for GCP preemptible VMs:

• No bidding required (unlike AWS Spot) — you get consistent low pricing.
• 30-40 second startup time beats AWS EC2's 1+ minute launch.
• 5-minute to 1-hour workloads fit perfectly within GCP preemptible's 24-hour maximum runtime (you'll get a 30-second shutdown notice if the VM is reclaimed).

Switching to AWS would introduce the very problems you want to avoid: bidding uncertainty, slower startups, and more operational overhead for spot instance management.

内容的提问来源于stack exchange，提问作者Gary Leong