The Life of a System Call: Who Actually Answered
Here is a small program. It opens a file, forks, waits for the child, asks its own PID and exits — five library calls, and I wrote every one of…
etcd, Honestly
Six stages, from the member that answered to the restore that hands your data back on a clock that has been wound backwards. Why a successful etcd restore can break…
The Life of a Unix Socket
Seven stages, from an object with no name to a name with no object. Why every diagnostic tool on the machine prints a path it never checked, why only the…
The Life of a Certificate
The six stages between an ACME account and a certificate your server is actually serving, and the two private keys that never meet. Why a renewal that succeeds proves nothing…
How a Path Becomes a File
Path resolution is not a function from strings to strings. The six stages between a pathname and an open file: the trailing slash that defeats O_NOFOLLOW, why .. is a…
The Life of a File Descriptor: Seven Stages from open() to close()
A file descriptor is a small non-negative integer, and almost everything difficult about Linux plumbing comes from one fact about it: the number is yours, and the thing it points…
Kubernetes, Honestly: Seven Stages Between kubectl apply and a Running Container
You run kubectl apply -f deployment.yaml, wait, and a container is running on a machine you did not choose. Between those two moments sit seven stages, exactly two synchronous calls,…
The Life of a Package: Eight Stages Between apt install and Working Software
You type apt install nginx, watch some text scroll past, and have a web server. Between those two moments sit eight stages, two entirely different trust models, and one asymmetry…
The Life of a Login: Seven Stages Between a Password and a Shell
Somebody types a password and gets a shell. Between those two events sit seven stages, several configuration systems that do not know about each other, and a set of decisions…
What Happens When You Type a URL: The Six Stages Before Anything Is Rendered
It is the oldest interview question in web engineering, and the answer everybody links to is roughly a decade out of date. The canonical write-up on GitHub still describes the…