Okay - I'm intrigued. How do you recommend managing infrastructure which consists of thousands of servers? With k8s - you just delete the pod and it gets recreated with a clean image within a few seconds. What's your proposal?
Seriously though, payment infrastructure actually is known for its reliability and fault tolerance. Banking systems don’t go offline terribly often.
Nowhere did I say you should be on one incredibly large server, nor that you should have a single point of failure. That wouldn't be simple, either, because it would fail to support the prime directive, or would require a great deal of gymnastics to. It's about balance. You don't need thousands of servers to make a reliable system.
I don’t know if they have a specific reputation for it. But their services were very reliable and resilient.
> The main reason banks don't go offline is because the core critical infrastructure is running on 50 year old mainframes that no one is allowed to touch because all of the greybeards with actual talent who made them are pushing up daisies.
This isn’t really true at all. The banks central ledger will likely be running on DB2, and that will almost never fail. But most of their infrastructure runs on more “modern” systems (DB2 is still modern if we’re being honest, it’s just more specialized). When you swipe your card somewhere, nearly all of the systems the transaction passes through are ordinary web services, running on ordinary architecture. That’s where the greatest risk of service disruption is. It’s just the final side effect is updating a record in a DB2 database somewhere.
Most banks also outsource a lot of the core system maintenance directly to IBM. A typical software or infrastructure engineer in a bank will have absolutely no contact with those systems.
> Nowhere did I say you should be on one incredibly large server
No, you just seem to think that reducing the number of components in your infrastructure is the key to reliability. If you want fault tolerance, then you generally want redundancy, and you want your services to fail gracefully (ie, not take down other non-dependant services when they do). Both of those things require deploying more servers.
If points of failure are a concern, then you also need to account for the fact that every single time you make a manual change you are creating a new point of human failure (with humans generally being the least reliable part of any well designed system). If you automate a change, you can spend more time scrutinizing it for mistakes, and be reasonably sure it’s deployed exactly the same everywhere. Combine that with blue/green, rolling or canary deployments, and automated testing, and you end up with something much more reliable than shelling your way across the entire infrastructure to deploy a single change. To suggest that deploying less infrastructure is a superior alternative really just comes across as ludditism.
What makes banking systems reliable is that there's so much built in latency in every operation that nobody really notices if something is down for six hours.
This is true for settlement, but not authorization. When you spend your money it could be hours or days until the transaction is correctly reflected in your balance. But in order to spend it in the first place the transaction has to be authorized, and this happens in real time. Depending on where you live, who you bank with, what kind of card you’re using, how you’re using it... this authorization may rely heavily on your bank being available for online transaction processing, or not very much. But unless you’re doing a transaction with one of those imprint devices, your transaction must be authorized in real time by somebody.
I carry some cash too. But the times I’ve needed it were for things like an outage of the internet connection at a restaurant, or an issue with a payment terminal provider (or for the very uncommon cash-only merchant).
> Nowhere did I say you should be on one incredibly large server, nor that you should have a single point of failure. That wouldn't be simple, either, because it would fail to support the prime directive, or would require a great deal of gymnastics to. It's about balance. You don't need thousands of servers to make a reliable system.
Heh those things go offline every night for 2 hour maintenance.
Also fun when those nice single points of failure crash (they do)
Source: work at a shop trying to _get out of_ greybeard mainframe to get more reliablity
How large is the company you work for (employees or revenue)? How many servers do you have to support that company?
“SourceHut [of which ddevault is the founder] has 10 dedicated servers and about 30 virtual machines, all of which were provisioned by hand... [It] made 4 thousand dollars in Q1 with two employees and an intern.” (from https://sourcehut.org/blog/2020-04-20-prioritizing-simplitit...)
> Oof... The smartest people I know generally assume the least of situations they are not intimately familiar.
Yeah, I generally think highly of Drew’s opinions on technical matters, but this thread is just painful to read.
Anyone whose properly managed more than a few servers realizes and understands this.
The correct way would be to just document the changes.
Maybe "don't have thousands of servers" is just a bad take :)
You haven't caught on that no one has said automation replaces testing or other processes but that seems to be the drum you're banging on. Ansible or whatever tool doesn't replace testing, monitoring, pentests, whatever else you want to do. Automation lets you fix the issues faster and replace servers faster and more reliably, once you have done the testing that you have to do either way.
Another part of the problem is that in the past they invested in every platform under the sun that ran the financial applications they required, so there was a lot of legacy platforms that they couldn't yet rationalize away (AIX, Solaris etc).
The other problem is that they are incredibly risk averse, and thus will build new platforms extremely slowly and only after immense testing will they cut over from the old platform to the new platform. They are typically averse to consolidation or rationalisation since the ongoing stability of the application is the most important factor to their business.
A virtualization umbrella project that I was working on 10 years ago for this bank that covered several "core" platforms (AIX, VMware, Solaris, etc) is still under way as we speak, with many applications still to be migrated from old platform to the new one, despite the original "replacement" hardware now being obsoleted by the manufacturer already, according to those I know that still work there. I wonder if they'll ever finish.
Now, at my current gig - we have 43 nodes - but each node can run 100+ k8s pods (and, they are beefy 768 GB nodes). Our administration overhead, in terms of people/effort/auditing is a fraction of what it was at the last gig. Also - Disaster and failover is just a matter of bringing up the clusters and persistent stores in another region. No need to keep compute on standby. This week, we're even doing a migration of a cluster from GKE to Azure. And it started out on AWS (though not in production) - I'm not in the sysadmin world anymore, but from what I've seen, things like k8s have made it a heckuva lot easier to do big things with fewer people.