Share a drive read-only - sandkiln

A common pattern: one drive holds data or a base layer many sandboxes need to read, but none of them need to write. Read-only sharing exists for exactly this — no per-sandbox copies, no coordination needed.

Seed it once

A drive read-only-shared later still needs writing at least once, before anything ever attaches it read-only — a read-only mount can’t format or write to it.

curl -X POST http://127.0.0.1:7777/drives -d '{"size_mib": 512}'
# {"id": "<drive-id>", ...}

curl -X POST http://127.0.0.1:7777/sandboxes \
  -d '{"drives":[{"id":"<drive-id>"}]}'
# attach read-write, seed it, then stop this sandbox (or delete it with ?keep=false)

import { Drive, Sandbox } from "sandkiln";

const drive = await Drive.create(512);
const sandbox = await Sandbox.create({ drives: [{ id: drive.id }] });
// attach read-write, seed it, then stop this sandbox (or delete it with keep: false)

from sandkiln import Drive, DriveAttachment, Sandbox

drive = Drive.create(512)
sandbox = Sandbox.create(drives=[DriveAttachment(id=drive.id)])
# attach read-write, seed it, then stop this sandbox (or delete it with keep=False)

kiln drive create 512
# prints the new drive's id

kiln sandbox create --drive <drive-id>
# attach read-write, seed it, then stop this sandbox (or `rm --destroy`)

Attach it read-only, as many times as you need

curl -X POST http://127.0.0.1:7777/sandboxes \
  -d '{"drives":[{"id":"<drive-id>","read_only":true}]}'

const reader = await Sandbox.create({ drives: [{ id: drive.id, readOnly: true }] });

reader = Sandbox.create(drives=[DriveAttachment(id=drive.id, read_only=True)])

kiln sandbox create --drive <drive-id>:ro

Repeat this against as many sandboxes as you want — every one succeeds, concurrently, as long as every existing holder and every new attach are all read_only: true. A single read-write attach — existing or newly requested — still needs exclusive access; see Drives for the exact rule.

Check who’s holding it

curl http://127.0.0.1:7777/drives

const drives = await Drive.list();

drives = Drive.list()

kiln drive ls

attached_to lists every current holder (sandbox <id> or snapshot <id>) with its read_only flag — useful for confirming a conflict’s actual cause, or checking a drive is free before deleting it.