Blog — page 3 of 38
Firecracker vs FreeBSD Jails: Two Honest Answers to the Same Question
Jails predate Linux containers by a decade and are better designed than them. They also share the host kernel, which is the entire comparison. Everything else is downstream of that one sentence.
Audit Trails When the Machine Is Gone in 200 Milliseconds
The thing that makes a sandbox safe — it is destroyed — is exactly what makes "what did the agent do at 03:14?" unanswerable. You cannot keep the machine. You can keep its memory and disk.
Top 10 Disposable Development Environment Platforms in 2026
Creating environments is the easy half. This is a roundup graded on the hard half: what actually gets destroyed when you destroy one, what survives that you did not plan for, and who else feels it.
Top 6 Throwaway Postgres Platforms for Testing in 2026
A database for a human to poke at and a database for forty parallel CI jobs are not the same product. The axes that decide the automated case are parallel isolation, seed-cost amortisation, and what leaks when a run is cancelled at 40%.
Running MATLAB and Octave Workloads in Isolated microVMs
Most runtime isolation problems are technical. This one starts with a contract: you cannot fan out 200 MATLAB processes without the entitlements to match. Here is the honest version — licence manager, MATLAB Runtime, Octave's real compatibility cliff, and why the guest boundary wants to be a VM.
Self-Hosting a Compiler Explorer: Running Strangers' Compilers Safely
"I'm not running their code, I'm only compiling it" is the most expensive sentence in this genre. A compiler is a programmable machine with a filesystem, a plugin loader and an unbounded appetite for RAM — and on a compiler explorer, the flags are user input too.
Optimisation Solver as a Service: Isolating Jobs That Run for Hours
Nearly every compute platform assumes it can predict how long a job will take from the shape of its input. A mixed-integer program is a counterexample: the same model class solves in 200 ms or runs until you stop it, and nothing in the file tells you which. Everything downstream of that — timeouts, memory, placement, reproducibility — has to be designed for the bimodal case.
Notebooks in Production: Parameterised Runs in Disposable microVMs
The quarterly board metric comes out of cell 34, which must be run in order, by Dmitri, on his laptop. The notebook is not the problem. The laptop is. Papermill turns the notebook into a batch artefact; a disposable microVM per run turns it into one you can trust.
Build, Boot, Test: Kernel CI on MicroVMs (and Where It Stops)
"Does this patch boot" should be a per-commit check, not a nightly. A microVM makes the boot step sub-second and a git bisect a coffee break — right up to the device model, the nested-virt wall, and the fact that you cannot swap our guest kernel.
Shadow Traffic and Replay: Testing a Rewrite Against Real Requests
Nobody wrote down what the old service does, and some of its bugs are load-bearing. Production traffic is the only artefact that has never been wrong about it — which makes diffing two implementations against the same requests the only honest test you have. Then the mirrored POST charges the card twice.
Mutation Testing at Scale: Thousands of Broken Builds on Purpose
A test suite is a claim: that if this code were wrong, something here would fail. Mutation testing is the only honest way to check that claim — break the code on purpose, thousands of times, and see what the suite notices. Which makes it a scheduling problem.
Your Dependency Bot Runs Strangers' Install Scripts
An automated dependency bot is a privileged robot on a cron whose entire job is to fetch third-party code and run it. The fix is not to stop it executing — it is to make sure the thing executing and the thing holding the token are never the same machine.
Top 7 Ephemeral Development Environment Platforms in 2026
An environment is ephemeral when it is created from a definition, nobody is sad when it dies, and the 400th costs the same as the 4th. Most "cloud dev environments" fail at least one of those tests.
Top 8 Throwaway Postgres Platforms for 2026
A disposable database is not a feature, it is one of three mechanisms with genuinely different properties — and the one that starts empty can only ever run your unit tests.
Lighthouse and axe-core Audits, One MicroVM Each
Forty Lighthouse runs sharing a kernel all report a worse LCP than the truth, and the variance swallows the regression you were hunting. The isolation here is not a security control — it is a scientific one.
One microVM per Attendee: Hands-On Labs for a Whole Room at Once
Two hundred people arrive inside the same ninety seconds, all do the same thing at the same time, and all vanish at 5pm. That load shape breaks pre-provisioning in both directions — and it is exactly what snapshot-restore-per-create is for.
Extracting Untrusted Archives: Zip Bombs, Zip Slip, Symlink Escape
Archive extraction is one of the few operations where the attacker picks the amplification factor. You cannot inspect your way out of that. You can only put it somewhere you are willing to lose.
A Regex Is Untrusted Code That Does Not Look Like Code
Nobody reviews a regex in a form field as code. But a nested quantifier on a backtracking engine is a denial-of-service primitive with a one-line source file — and the attack payload is usually a badly-typed email address, not a pattern.
Can Firecracker Run Windows? No, and the Reason Is the Point
The answer is no, and it is not an oversight or a roadmap item. It falls out of the one decision that makes a microVM boot in milliseconds — and the set of guests Firecracker does support tells you exactly why.
Cold Start Is Four Problems: JVM Warmup vs the microVM Snapshot
A Firecracker snapshot is a memory image, and a warm JIT lives in memory — so snapshotting at the right moment fixes a layer of cold start that nobody expects it to. Then it hands you a guest that believes it is still last June.
Locale, Timezone and Encoding Bugs That Only Appear in Ephemeral Sandboxes
Your code did not change. The environment's opinions changed — and a snapshot makes them permanent in a way a container restart does not.
Julia, R and the Cost of the First Import
Web runtimes are cheap to start and expensive to run. Scientific runtimes are the opposite: the first call is catastrophic and every call after it is free. A sandbox that starts clean throws away exactly the cache that matters — unless the sandbox is a memory image.
What FedRAMP Asks of a Platform That Runs Untrusted Code
An ephemeral-by-design fleet is hostile to a control set that assumes a stable, enumerable inventory — and a snapshot memory image is an asset class nobody wrote a control for.
Distributed Data Processing on Ephemeral MicroVM Fleets
Fork sixty-four workers from one parent that has already resolved the dependency closure, and they will be running in under a second. Ask any two of them to exchange a shuffle block and the host firewall will drop the packet, by design.