To come up with our on-prem compute costs, we baked in the cost of power, real estate, staff, taxes, network infrastructure, servers (both in-use and in reserve), etc. On the AWS side, we used 3 year RIs and Savings Plan. After all that, there was around a 30% cost advantage on-prem. That's non-trivial, but not as big as one might think.
Outbound networking, however, is ludicrously cheaper on-prem. It's about 85% cheaper on-prem than in AWS. Bandwidth is not expensive outside the public cloud.
In fact, egress volume is the #1 cost driver for us moving a service on-prem or building it there to begin with. Some of the AWS managed services are also very pricey, but nowhere near the egregious markup of egress bandwidth.
the notion, "the cloud is expensive", ignores the fact that the cloud is not just rented hardware, but staff, facilities, planning, management, etc..
there are businesses where it makes more sense to own hardware and employ your own staff, but if you just want generic compute and storage, you're unlikely to do it as well for less.
also you cannot easily source arm hardware commercially, there is the honeycomb lx2, and its' lead time is months for a single unit. if you want hundreds of nodes, you're gonna use a cloud provider who manufactures their own silicon.
(I'm guessing self-host realistically means "get a VM on AWS", which is probably fine for CI if you already use AWS. A little annoying to have another monthly bill to pay if you don't, though.)
https://www.reddit.com/r/googlecloud/comments/vy8hx3/ama_wit...
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