Since 2013, I have tried to adhere to the detailed steps written in this Continuous Integration recipe which have always served me well. Obviously managing a plethora of websites well on a public server is a serious undertaking.
And please keep in-mind, no matter how small your business requirements, (and investments), might be initially, no one outgrows free, open-source Drupal, which is why governments consistently choose to use Drupal to best communicate and interact with their constituents.
Imagine what high value websites, such as fbi.gov or justice.gov, are to hackers. Those United States Government websites are built with Drupal, as are most government websites in The World, by far, (as are most large-budget, important websites, period). So of course not just any common data center arrangement will do for the United States Federal agencies, which is why the US FedRAMP security assessment, authorization, and continuous monitoring for cloud products and services exists.
Imagine a holiday or weekend, (or night), when the, (certified), Drupal developers aren't working and available, can't be reached, and the website is hacked. That's why websites are hosted in a FedRAMP maintained environment.
Acquia is the 800 pound corporate gorilla in the Drupal economy and provides both an extremely profitable FedRAMP hosting business, and certification services for Drupal developers like me, which makes sense for Acquia's profit-driven quality control motivation when you think about their certification program. I doubt their certification department generates serious, interesting revenue for Acquia otherwise.
Stepping away from government examples, Acquia isn't the only closed-source hosting company. A few others are Pantheon and Platform.sh. All of these are examples of closed-source hosting companies because as an open-source Drupal developer responsible for my own development and testing resources, I have no idea how their servers are configured. Meanwhile, developers like me are constantly asked by clients to use their chosen interfaces and processes. And these hosting companies charge by the website, and I'm just a single developer, so what to do for my own recommended hosting requirements?
Of course I turn to open-source, and given my long history with Drupal I'm familiar with the storied history of Bright in Vancouver and how they open-sourced their server software when Bright's business sadly collapsed, (and most of those developers went on to found Acquia). The name of this server code is called Ægir, which means a personification of the sea in Norse mythology, and has been continuously developed ever since, and many variations of it exist, such as OpenDevShop.
However I'm here today to sing the praises of BOA, which is an acronym for Barracuda, Octopus, and Ægir. I've been using this public-facing server Distribution for well over a decade. It's free and makes for a mighty $20/monthly hosted server capable of managing hundreds of sites if need be, with satellite, load-bearing recipes, and a wonderfully reliable migration workflow. Do not forget, for every website probably exists a Development, Staging, and Production version in the very least. For more information about BOA, this article explains it very well. So who maintains such a professional, trusted tool? Omega8.cc who also sell support for the open-source public server software I use and trust.
Unless the website requirements don't require any fancy stuff, in which case Tome is a great way to make a super-efficient, static website cable of being hosted for less than the price of coffee, (think brochure-ware with no interactivity possible, so nothing like a 'contact us' form is possible). If that's your only business requirement, you can host your static website at Dreamhost using their Shared Unlimited subscription for less than the price of a single coffee/monthly, (while still enjoying all of Drupal's user-friendly content management features to update your multiple domains/email addresses/websites upon your whim and fancy, while also including https/SSL encryption).