> Then, at some point, that dynamic changes as you have a better understanding of your needs, the bills start to build up and the architecture is in less flux. You might also have a bigger team and can afford to start allocating more resources to operation. That is the point when it it might make sense to migrate over to self-managed.

I completely agree, and I had this discussion with my direct manager in the past. Yet, even if the potential savings are significant, managers might not be too keen on investing on switching your infrastructure. Running your own infrastructure is risky, and although top managers enjoy lower utility bills they don't enjoy the sight of having a greater risk of suffering downtime, specially if the downtime is self-inflicted and affects business-critical services.

So, if this transition doesn't go perfectly smoothly... The people signing for the migration to self-hosting services might be risking their whole career on a play that, at best, only brings some short-term operational cost savings. Does this justify a move whose best case scenario is equivalent to a AWS discount?

For sure, there are a lot of factors to consider here. For heavy workloads where you need solid I/O, the cost for the same performance on baremetal vs VMs on cloud can be >4x so you could even afford to have a duplicate setup on another network for redundancy and still be saving.

Moving workloads in-house does happen. But, in general, you're right. It's hard to advocate for a near-term expensive (in time and money) and at least somewhat risky (expect some nights and weekends crises) migration for possibly some longer term cost benefit (assuming you've accounted for all the costs). Which BTW neither you nor your manager may still be around to take credit for. And also BTW is at least somewhat counter to what companies are doing in general, for better or worse, and which execs will probably rightly see as a potential distraction from whatever the company is trying to accomplish.

Frankly the whole discussion mostly highlights that these are things you need to think about upfront before you're fully committed.

Back in the day, when I was part of a startup, the DB guy was all into making us write “provide agnostic” sql in case we ever wanted to switch to Mysql or Oracle. We were actually using Postgres. This was a nightmare.

Things started improving when we said ‘f-it we are not moving out of Postgres, let us at least use the best features of PG’

There is a similar problem when trying to use AWS with the constant thought about moving out of AWS at some point.

Yeah, this is a bit what I mean with doing it pragmatically - at least when you choose provider-specific services know that either 1) you have an idea of how you would migrate it or 2) it is a conscious decision to leverage a USP. By taking the provider-agnostic paradigm to the extreme, you have the least common denominator, getting none of the upsides.

> Start out on AWS/GCP/Azure in the initial phase when you want to optimize for velocity in terms of pushing out new functionality and services.

Have you ever done this? It's exorbitantly hard to migrate off of a cloud provider, and few ever do.

I agree that migrating off a cloud provider can be very hard. However, architecting your system with portability in mind can help a lot, as rumanator points out:

> I think building somewhat cloud-agnostic to ease friction of provider migration is good

Of course, that's not always an option if the system is already built, but it's definitely a good approach.

I have and It’s only hard if things aren’t dockerized imo. If everything is in something like cloud foundry it will be much harder.

If you don’t have heavy AD and policies in place even better.

+1 on containerization, and I would add that controlling your container orchestration service (particularly ingress and security) is another key factor. Whether someone uses Docker Swarm or Kubernetes, this setup enables anyone to redeploy their entire applications at a blink of an eye, regardless of which cloud service provider you use.

If your entire infra is dockerized, you are in the vast minority and should probably be discarded as an outlier.