Tuesday, 25th of Jun 2019
The Serverless Post Office
Post Offices don’t need servers! Which is why they make the perfect example to explain the benefits of serverless in a practical example that everyone can understand.
A Post Offices purpose is fairly simple, mail is dropped off and it gets sorted, then delivered to its final destination.
In order to deliver mail through a traditional setup there are a lot of overhead.
A physical building is required to collect and sort the mail. Rent is paid on the property Electricity is needed to keep the lights on because mail can’t be sorted in the dark. Building maintenance is required to stop the whole place falling into disrepair. The buildings need a fit out of things like cash registers to keep the postage stamps safe and locks to ensure the mail isn’t stolen.
All these overhead costs are charged monthly and they continue to tick over regardless of the Post Offices opening hours or inbound mail. Let’s say these equal $100 per month.
If one letter is dropped off for delivery in a month, the cost of that delivery is $100. Whereas if 100 letters are dropped off, the cost per delivery is reduced to $1 per letter - a bit more reasonable. What is 1,000 or 100,000 letters were dropped off? Great! We can get the cost down to $0.10 or $0.001 per letter - awesome! When running at low capacity it’s very expensive, but at scale it’s super cheap.
However, with the reduced cost comes the pain of slow delivery, the mailroom cannot sort and deliver all the mail, more letters are coming in then going out, it keeps piling up. To deal with this problem new Post Offices are required, which brings all those fixed overhead costs to a new location and it causes the average cost per letter to increase again.
This is how traditional Post Offices work, a serverless one is totally different.
When utilising serverless mail delivery the overheads are no longer a fixed monthly cost, instead they are costed at a per letter basis, let’s say $0.005 per letter. Once a letter is dropped off the Post Office is created, lights are turned on, cash registers are installed, mail is sorted and pushed out the door. The staff then leave the Post Office and shut it down.
The serverless Post Office can handle so many letters, they can keep coming in, and instead of ending up in a huge pile and delaying their delivery, the Post Office simply opens another store and the workers start processing the new mail in that location.
That cost per letter stays the same, 1 letter with one Post Office is $0.005. When a flood of millions of letters come in and hundred of thousands Post Offices open their doors to process all the letters, the cost remains $0.005 per letter processed.
More towns are starting to use these types of Post Offices because they make a lot of sense, and their letter business is unpredictable and sporadic, around Christmas time it booms, around Mother’s Day and Father's Day it gets a healthy flutter. It isn’t worth having all the traditional Post Offices sitting idle, paying all those fixed costs just so they can process mail several times a year, instead towns want serverless!
Understanding the serverless paradigm with this Post Office example has hopefully helped you understand what servlerss is?.
Substituting the examples with a practical example can be done with the following translation table.
|Rent||Datacenter / Rackspace costs|
|Electricity Costs||Running costs|
|Building Maintenance||System maintenance / patches|
|Collecting Mail||Ingress packets|
|Office Fitout / Cash Registers & Locks||Software & Security|
|Delivering Mail||Egress packets|
|Towns||Customers / System admins|
If in the near future we can take serverless practices offline then I’m sure Post Office customers & towns would love the idea of serverless. Unfortunately no one has worked out how to clone a building and its workers instantly, and cease their existence just as quickly. For now it’s confined to the IT world and Franklin loves it!
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