> We don't expect most web sites to use it.

A fortiori, this indicates it was perhaps not a great use of engineering resources.

> Most of the world is still waiting.

Sadly true. If anyone wants a sobering overview of vaccination around the world, I suggest checking out this site (https://timetoherd.com/). But this has to do with the fact that vaccines are in short supply rather than websites crashing due to http requests. A Cloudflare internet waiting room does nothing to alleviate that global supply problem.

> As I tried to explain in my previous reply, there is no general solution that would allow infinite scalability of overlapping transactions.

True as well. There is no disagreement here. There will probably never be absolute perfect global consistency in a network of networks with distributed computing and storage. That does not mean you cannot attempt to increase the consistency. Similarly, you will probably never reduce http request response times to 0ms or reduce worker processing times to 0ms. But you can (and are trying to) reduce the latency as much as possible.

> For example, if you want to store a counter that can be atomically incremented, there are ways to scale that by using a tree topology with branches aggregating batches of requests to submit to the root node.

That seems like an interesting avenue to pursue. It definitely would be a better use of engineering resources.

> You have to consider not just the technical challenge here, but the human organizational challenge of software development and speed of deployment.

Sure. You also have to consider that this is not just a network engineering problem. It is a product design problem as well. And that there is a risk of over-engineering an unwarranted solution. When I said design to scale from the ground up, I did not mean exclusively from a network standpoint.

Let's quickly walk through a potential product design for vaccination. As has been done in many cases, folks can be pre-assigned an appointment time and day and location. There are indications that this actually increases overall attendance. This also has the added benefit of reducing the operational software challenges you allude to. No need to worry much about devops. This would simplify implementation greatly. The appointments can even be batch processed offline one by one asynchronously.

I can elaborate on this design and could anticipate your likely objections. But that is beyond the scope of this reply. The takeaway is that there is a product design solution that largely does away with the network engineering problem of having too many synchronous realtime requests for potentially inconsistent data.

> That's valuable, and it has actually helped a lot of people get vaccines in the real world

Let's assume the synchronous solution for the entire population is the only solution. And that the server crashes returning a 503. It may not be good from Cloudflare's perspective. But the question is did it help or hinder vaccination.

You seem to accept as a foregone conclusion that it would hinder. Let's entertain the possibility that it helped.

Those that are keen to vaccinate will try again in an hour or whenever the server is back up. If anything, it will more evenly distribute the requests over time. Those folks would vaccinate regardless of whether there is a Cloudflare internet waiting room.

How about those that were reluctant to vaccinate? Let's assume they think getting the vaccine is unreasonable. Stories of the website crash may be on the local evening news. These previously reluctant folks may feel like they might miss out. They might begin viewing getting the vaccine as a more reasonable option.

You might think this is absurd. Is it as absurd as otherwise reasonable folks hording toilet paper during the early lockdowns? Are you certain none of your Cloudflare colleagues were among those folks?

The internet system is complex. The vaccination system is complex. I do not presume to understand all the ins and outs of either let alone both.

I am not criticising the team members. I am sure they are competent and well intentioned individuals
who just wanted to do their part to help out with the vaccination.

What I posit is that the internet waiting room is inconsistent with the mission of Cloudflare for a better internet. Any suggestions that an internet waiting room for vaccination was a net positive for vaccination and better than all other practical alternatives are dubious at best.

The information presented thus far has not led me to reconsider this position. But I am still open to reconsidering. You are more than welcome to invite the actual team behind the internet waiting room. Perhaps they can share some insights into their rationale at the time. Hopefully they can approach the exercise with a reciprocal willingness to reconsider their own positions.