If you want to run a validator node, you will first need a machine that is powerful enough to facilitate all of the required computation. We understand that for practical reasons a lot of the validators will choose one of the cloud providers. That said, the best thing from a decentralization standpoint is to run the node on your own machine.
A general remark for choosing your hardware setup is that you want the machine to have fast I/O. As such, NVMe SSD disks are recommended, as well as making sure that the network has low latency and is reliable.
Below you will find a reasonably powerful setup that should allow you to run your node comfortably, without worrying about the 'hiccups' (which can impede block production).
- CPU: modern desktop x86_64 (Intel, AMD) processor with at least 8 cores
- RAM: 32GB
- Storage: 2TB NVMe SSD
- Network: 100+Mbps (with low latency)
- AWS: c5d.2xlarge or, more comfortably: c5d.4xlarge
- GCP: c2-standard-8
- Azure: F8s (+ additional persistent storage)
A closing remark would be that while most of the times you could get away with using slightly less powerful machines, it becomes a gamble that validators usually want no part of.