the complete set

Everything crucible does.

One static Go binary: the daemon, the CLI, the TUI, and the MCP server. Runtime through platform, isolation through observability.

Isolation & security

Firecracker microVM per sandboxEvery workload is a real hardware VM with its own kernel.crucible run

Jailer + KVM confinementchroot, seccomp, cgroups, and dropped capabilities around each guest.--jailer-bin

Per-sandbox network namespaceOwn veth, subnet, DHCP, and DNS proxy; no shared network.netns

Default-deny egressNo network unless allowlisted by hostname or public CIDR.--net-allow

SSRF range-filteringMetadata, link-local, and RFC1918 blocked even with full egress.--net-full-egress

Scoped policy tokensAPI keys bound to operations, egress ceilings, resource caps, and expiry./whoami

Resource capsPer-sandbox vCPU, memory, disk, and timeout ceilings.--memory --vcpus --disk

The fork primitive

Live snapshotFreeze a running guest: memory, page cache, and writable rootfs.snapshot create

ForkBranch independent copies of a snapshot in about 125 ms.fork --count

Lazy userfaultfd memoryChildren page in only the working set they touch, not full guest RAM.userfaultfd

Copy-on-write rootfsO(1) disk clone on reflink filesystems; hundreds of forks bounded by RAM.--work-base

Clone-safetyReseed RNG, rotate machine-id and netns before a fork is reachable.fatal-before-reachable

Images & files

Boot any OCI imageRun unmodified Docker images in a microVM, no rebuild.crucible run <image>

BuildTurn a Dockerfile context into a bootable image.crucible build

Private registriesPer-registry credentials feed every pull, including app re-pulls.registry login

File push & pullCopy files and directories into and out of a live VM.crucible cp

SizingGrow the rootfs and set memory and vCPUs per run.--disk --memory --vcpus

Prebuilt profilesEight language and runtime rootfs profiles out of the box.--profile

Durable apps

Deploy durable appsDesired-state services the daemon keeps alive across restarts.app create

Reach by nameAn ingress proxy routes web.<domain> to the current instance.ingress proxy

Self-healingA crashed instance is reconciled back from spec automatically.reconcile

Zero-downtime updatesBoot, health-gate, flip the route, drain the old instance.app update

Config & healthEnv vars and exec health checks per app.--env

Operate by nameexec, logs, and shell resolved to the current instance per call.app exec / logs / shell

Scale

Scale to zeroIdle apps sleep to ~0 RAM and wake in place in about 125 ms.--min-scale 0 --idle-timeout

Scale outN replicas forked from a golden snapshot, P2C load-balanced.--min-scale --max-scale

AutoscaleReplica count tracks request concurrency.autoscale

App-to-app networkingPrivate, default-deny calls between apps at <app>.internal.--can-call

Observability

Per-app metricsRPS, latency, errors, replicas, and wake counts on /metrics./metrics

OTLP exportMetrics and logs to any collector; honors OTEL_* env.--otlp-endpoint

Grafana dashboardA reference dashboard ships with it.grafana-dashboard.json

pprofDaemon profiling on a loopback-gated port.--pprof-listen

Packet captureHost-side pcap of a sandbox or app, on demand.sandbox capture

Durable logsPer-sandbox logs that outlive the VM, streamable live.crucible logs -f

Interfaces & control

CLIA fast, scriptable command for every operation.crucible

TUIA live terminal dashboard of sandboxes and apps.crucible tui

MCP server27 scoped, policy-gated tools so agents drive the runtime.crucible mcp serve

Go SDKThe typed client the CLI, TUI, and MCP all use.sdk

One REST APISpec-generated and drift-checked, documented byte by byte.openapi.json

API-key authOff on loopback, required everywhere once any key exists.bearer

on any Linux + KVM box

One binary. Install and run.

The installer provisions Firecracker, jailer, and the guest kernel, then starts the daemon under systemd.

$ curl -fsSL https://github.com/gnana997/crucible/releases/latest/download/install.sh | sudo bash -s -- --with-deps --enable

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