Run a container or microVM

A compute workload runs a long-lived server — a container image or a microVM — behind a route, next to your static content and Wasm handlers. Use it when a Wasm handler is not enough: an existing container image, a language runtime, or code that needs a full OS. For the choice between a handler, a container, and a microVM, see Compute: handlers vs containers vs microVMs.

Compute backends are Linux-only and capability-detected at startup: a container backend where the host allows it, and a microVM backend where /dev/kvm exists. Enable compute by adding a compute: section to boatramp.cfg (see the schema).

Deploy a container image

compute build takes an OCI image reference, builds an ext4 root filesystem from it, uploads it, and registers the workload in one step. It needs the mke2fs tool (e2fsprogs) on the host and a kernel blob provisioned once.

boatramp compute build web \
  --image nginx:1.27 \
  --kernel <vmlinux-blob-hash> \
  --port 80 \
  --vcpus 1 --mem-mib 256 --replicas 2

built ext4 rootfs from nginx:1.27 (1024 MiB) — blob sha256:1a2b…
workload web set: 2 replicas, port 80, isolation trusted

The scheduler places the replicas on nodes that advertise compute capacity and reconciles them toward the desired count. Check status:

boatramp compute ls

NAME  REPLICAS  PORT  ISOLATION  STATE
web   2/2       80    trusted    Healthy

Choose the isolation level

--isolation decides which backend may run the workload:

boatramp compute build tenant-app --image ghcr.io/acme/app:1.4 \
  --kernel <vmlinux-blob-hash> --port 8080 --isolation untrusted

Under the strict multi-tenant security posture, shared-kernel (container) compute is disabled, so every workload runs in a microVM regardless of --isolation. See Choose a security posture.

Set a workload from existing blobs

If you already pushed a rootfs and kernel, register the workload directly with compute set (same flags as build, minus the image build):

boatramp compute set api \
  --rootfs <rootfs-blob-hash> --kernel <vmlinux-blob-hash> \
  --port 8080 --replicas 3 \
  --entrypoint /usr/bin/api --env LOG=info

Inspect a workload’s desired state:

boatramp compute get api

Next steps

• Scale compute to zero when a workload is idle.
• Load-balance & proxy upstreams to route traffic to it.