Original, source-backed articles about running small systems, static sites, HTTP, DNS, TLS, and operations.
Posts are original articles written for this site. Each one is script-free, source-backed, and tied to the same operational reality the rest of the site records: how a small, static, publicly served system is built, secured, and kept honest.
Postgres jsonb stores JSON for querying
PostgreSQL offers two JSON storage types with different representation costs. json validates and retains the input text, while jsonb converts it into a decomposed binary value. Both support extracting fields and paths. Choosing between them is primarily a decision about preserving representation, processing documents repeatedly, and supporting the operators your queries need.
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Cache freshness is judged against a clock
A cache does not receive a new freshness allowance every time another cache forwards a response. It must account for age already accumulated along the delivery path, then add its own residence time. Otherwise a chain of individually plausible sixty-second caches can keep old content reusable much longer than the origin intended.
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TCP window scaling enlarges receive-window encoding in each direction
TCP’s header has a 16-bit receive-window field. Window scaling lets established connections interpret that field using a shift negotiated during setup, allowing a receiver to advertise more than 65535 bytes of space. The two directions can use different shifts. The extension enlarges the encoding of receive-window information; it does not directly enlarge every buffer or guarantee that a sender will keep that much data in flight.
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A token bucket bounds admission and allows bursts
A token bucket bounds admitted work while allowing accumulated credit to be spent in a burst. It does not automatically space requests evenly, guarantee completed throughput, or cap the number of operations still running. Those are separate scheduling and capacity questions. The bucket’s two parameters describe a budget, not a promise that the service can perform it.
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A fencing token guards against a stale leader
A lease can expire while its holder is paused, yet the old process can resume and send a delayed write. The storage service needs a way to reject superseded ownership. A fencing token supplies an ordered ownership epoch that travels with each mutation. Its protection depends on the resource checking the token, not merely on a lock service issuing one.
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Shell positional arguments are a numbered list
A shell script receives an ordered argument list, not a single command-line string that it must split again. Positional parameters expose that list as $1, $2, and subsequent entries; $# reports its size. A small fixed interface can use these positions directly. Optional settings and flags benefit from explicit parsing, but either design still needs to define the permitted count, empty values, and failure behavior.
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A systemd oneshot completes one activation
A Type=oneshot service represents finite work whose startup completes when its start commands finish successfully. That makes it useful for setup steps and scheduled jobs whose completion matters to a dependent unit. The word oneshot describes one activation’s process model. It does not create a permanent record that prevents the task from running again after a restart, another activation, or a reboot.
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Kubernetes rolling updates replace pods gradually
Choose the release shape before its speed. Can old and new versions process requests together? Can they share storage and ownership safely? What happens if the new version cannot start? Those answers determine whether a Deployment should overlap versions with RollingUpdate or stop the old version before replacement with Recreate. The companion article handles rollout pacing and live observation.
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