Blog — page 5 of 38
Bare metal vs cloud VMs for running Firecracker
If you run microVMs, you run a hypervisor — and the layer underneath it is an architecture decision, not a procurement detail. Nested virt taxes every exit and every page fault; bare metal hands you the machine and the pager. Here is the ledger I actually use.
A plain-English glossary of sandbox and microVM terms
This vocabulary is genuinely confusing, and a lot of it is vendors using one word for three things. Here is the glossary I wish someone had handed me: 48 terms, each with the distinction that actually matters and the specific way people get it wrong.
Your benchmark ran at a different clock speed than production
The same core does not run at the same speed twice. Governor, turbo bin, how many neighbours are busy, thermal headroom and ramp latency all move it — which is why the first sandbox on a quiet host looks fast and the fiftieth on a busy one gets blamed on the platform.
Rate-Limiting the Network on a Per-Sandbox Basis
Everyone sets a CPU limit and a memory limit. Almost nobody sets a network limit, and then one tenant saturates the host NIC and every other sandbox on the box gets slow for reasons that appear in none of their own metrics. Here is where the enforcement point actually is, and which end of the veth pair it belongs on.
Spectre, Meltdown, and What a microVM Actually Protects You From
KVM stops a guest from naming host memory. It does not stop the CPU from guessing about it. An honest tour of the transient-execution families for people running multi-tenant compute — how to read your host's actual exposure, what the mitigations really cost, and the part no VMM choice fixes.
Immutable microVM Rootfs with dm-verity
"Read-only" is a promise the guest makes to itself. dm-verity is a Merkle tree the kernel checks on every block read — so tampering is detected rather than merely discouraged. Here is the wiring, the Firecracker boot args, and an honest account of what it does not cover.
Signing and Attesting microVM Templates
A signature over only the rootfs leaves the snapshot unsigned — and the snapshot is a fully booted kernel's memory, restored on every create without ever executing a boot-time integrity check.
Saying No Correctly: Admission Control for Sandbox Fleets
Almost no capacity bug is 'we ran out of RAM.' It is either a yes you could not fit, or a no you did not have to give — and the second one is more expensive, because it looks like your platform is broken.
Golden Images vs Snapshot Baking
A golden image removes install time. A snapshot removes boot time. Those are different costs, which is why the answer is almost always both — and why the snapshot quietly freezes your RNG, your clock, and anything that was in RAM at bake time.
Running Firecracker Under Nomad
Nomad will happily place a Firecracker microVM on a host, restart it, and register it in Consul. It will not clone your rootfs, build your network, restore your snapshot, or notice that the guest inside your perfectly healthy VMM process has been wedged for ten minutes.
The Best Multi-Tenant Isolation Platforms in 2026
You are not shopping for a sandbox. You are shopping for an isolation boundary between one paying customer and the next — and the right one depends entirely on what your tenants are allowed to do.
Scanning Package Postinstall Scripts in a microVM
The only reliable way to find out what an install script does is to run it — which is the exact thing you were trying to avoid. So run it somewhere disposable, with the network turned off, and let the package tell on itself.
Running Customer Trading Strategies in Isolated microVMs
Your customers write strategies. Your infrastructure runs them, next to each other, holding credentials that place orders. This is the untrusted-code problem with a P&L attached.
Isolating Customer-Managed Key Operations in microVMs
You shipped BYOK to close an enterprise deal. Now your process unwraps tenant A's data key on a heap that also serves tenant B — and a heap dump is a remarkably efficient way to violate a data-processing agreement.
How to add human approval to agent code execution
The gate that asks about everything gets clicked through by Thursday. The useful design asks about almost nothing, because isolation earns you the right not to ask.
The best AI agent guardrail tools in 2026, by layer
Most teams buy one guardrail product and think they're covered. The layers solve disjoint problems, and only one of them is deterministic.
How to run SWE-agent in a sandbox
SWE-agent hands a language model a shell over your repository. On a laptop, that shell also reaches your SSH keys. Here is the isolated version.
How to sandbox code from Cline and Continue
The approval prompts work — for about a day. Then you turn on auto-approve, and a model has an unattended shell next to your cloud credentials.
How many sandboxes should a multi-agent system have?
Most teams pick their multi-agent isolation topology by accident and find out which one they picked when it breaks. There are three, and the choice is decidable.
What is a deep research agent?
Every provider now ships something called deep research. Underneath the label they are the same shape: a loop that keeps searching until it decides it knows enough.
How to give a Haystack agent a code execution tool
Haystack thinks in pipelines and components, so the first question is not how to write the tool. It is whether code execution should be a tool at all.
Agent tool permissions, explained
Your agent has six tools and the whole authorization story is "the model decides". Here is where the decision should actually live.
How to hand off work between AI agents
A handoff summary is a lossy channel, and most chains use it as the only channel. Here is what to send instead, and how to hand over the environment rather than a description of it.
How to run a RAG pipeline in an ephemeral sandbox
Query time touches your own index. Ingestion touches whatever a user uploaded. Only one of those stages needs a kernel boundary, and it is not the one most tutorials worry about.