# Restore a cluster > Putting a cluster's identity back onto a re-flashed control plane from an adopted backup disk — the first-run-only window, why it needs no sign-in, and why your app data is deliberately left alone. Written for Rasputin 2026.08.5. This is the screen you use after the machine running your control plane died. You flash a replacement, plug your backup disk into it, and `/restore` puts your cluster's identity back onto the new box — your operators, your passkeys, your nodes' tokens, and your cluster's certificate authority. It is a rare, one-way, one-time job, and three things decide whether it will work at all. Check them before you start: - **The disk must have been *adopted*, not claimed as blank.** See [Only an adopted disk can be restored from](#only-an-adopted-disk-can-be-restored-from). - **The replacement must be flashed with the *original* cluster name.** See [The cluster-id refusal](#the-cluster-id-refusal). - **You need the passphrase or the recovery code.** Either alone is enough; without both there is no path. `/restore` is **not** part of first-run setup. It is reached from the sign-in page, or by typing the address. `` below is the name the dead cluster answered to, and `` the identifier of one backup. ## Do this 1. **Flash the replacement control plane with the same cluster name the old one had.** 2. **Plug the adopted backup disk into the replacement machine.** Restore reads the disk locally, so it must be on this box. 3. **Go to the sign-in page.** With a backup set attached it grows a section offering **`RESTORE FROM BACKUP →`** and names how many sets it can see. Typing the address `/restore` also works, including with no disk attached yet. 4. **Pick the disk under `1 · BACKUP DISK`.** If exactly one can be restored from, it is selected for you. `SCAN AGAIN` re-scans if you plugged the disk in late. 5. **Pick a generation under `2 · GENERATION`** — newest first, newest usable pre-selected. The **IDENTITY ONLY** notice then names every app volume that will *not* be restored. 6. **Under `3 · UNLOCK THE ARCHIVE KEY`, choose `PASSPHRASE` or `RECOVERY CODE`** and type your secret. A recovery code ignores dashes and letter case; submit stays disabled until what you typed reduces to exactly 32 characters, which is a useful check you dropped none. 7. **Press `RESTORE THIS GENERATION`.** The identity set is staged and verified, the control plane restarts onto it, and the page waits — up to four minutes — for it to come back reporting operators. 8. **Press `SIGN IN WITH YOUR PASSKEY`** and use the passkey you had before the machine died. 9. **Check your nodes.** They reconnect with the tokens they already hold and need no re-enrolling. A node enrolled *after* the re-flash holds the wrong certificate authority; the control plane re-delivers it automatically, shown under **Mesh → DEVICES** as `TRUST STALE · re-delivering`, which clears itself. 10. **Restore app data per app, from Apps, only if you need to** — see [Identity only, and why](#identity-only-and-why-your-app-data-is-left-alone), and [Restoring one app's data](/docs/your-apps/#restoring-one-apps-data) for that flow. ## Only an adopted disk can be restored from This is the precondition, and it is not decided on this page. It was decided on **Storage**, possibly months ago. A backup disk carries the two sealed copies of its archive key in its own marker file, and `/restore` needs those copies — they are what your passphrase or recovery code unwraps. - **A disk you adopted** — taken over as it stood — still carries them, and can be restored from. - **A disk you claimed as blank, wiped, or reformatted does not.** Claiming destroys the marker, and with it the only copies of the wrapped key. The archives may still be sitting there; nothing will ever open them again. **What you cannot take back.** That one. If you plug a disk in to restore from it and the drawer on Storage offers you both paths, adopt. The green callout says so in as many words: *"If you plugged this disk in to restore from it, this is the choice you want."* ## Why this page needs no sign-in, and when it closes forever The page and the two endpoints behind it are **unauthenticated**, and they have to be. A re-flashed control plane has no users, so there is no session to require and no passkey to present. Requiring one would make restore impossible in exactly the situation restore exists for. What gates it instead is the fact that decides whether a box is at first run at all: **does any operator exist?** The moment the first passkey is registered, both endpoints answer with a refusal and **stay closed for the life of the installation**. There is no setting, no override, and no re-opening. Visit `/restore` on a cluster that is already set up and the whole page is a refusal plus a `SIGN IN` button. **What makes that safe is custody, not authentication.** The control plane will only unpack an archive whose key *you* supplied, and only a key that proves it belongs to the disk in front of it: - The archive's contents are sealed under a key that exists only in two wrapped copies on the disk itself, openable by your passphrase or your recovery code and nothing else. - Before anything is touched, the supplied key must derive the **public key written on that disk's own marker**. A key that opens some other disk is refused. - There is deliberately no separate signature to check: a signing key that survived a re-flash would be the same custody problem over again. So restoring onto a fresh box needs all three of: reach to a freshly flashed machine on your network, your backup disk physically plugged into it, and your custody secret. That is a description of you, doing the thing this page is for. It is the same open window that first-passkey registration already accepts on a fresh box on a private network, and it closes at the same moment. **What that does not protect.** Restore stays open until the first passkey is registered, and the archive secret is the only thing authorizing it. So the practical care is ordinary: keep the backup disk and its secret apart rather than together in the same bag, and register the first passkey on a replacement box once you are done rather than leaving it unfinished. **What you cannot take back.** Registering the first passkey. Do the restore *before* you create an account on the replacement — getting back to this page afterwards means re-flashing the control plane onto a fresh partition. ## Where your secret goes The page states it under the form: *"The secret never leaves this browser. It unwraps the disk's archive key here; that key is checked against the disk, sent once to the controlplane over its secure connection, and discarded on both sides when the restore ends."* That is literally what happens. Your passphrase or recovery code is used **in the browser** to unwrap the disk's archive key. The browser then checks that the unwrapped key really belongs to this disk before sending anything. The control plane repeats that check on its own side, against the marker it reads off the mounted disk rather than the listing your browser worked from — so the two catch different things: a wrong secret never leaves the browser, and a right-looking key aimed at the wrong disk is stopped by the control plane. Only the unwrapped key is transmitted, once, for this one restore, and both sides overwrite their copy when the restore ends — bar one copy of the encoded key inside the request itself, which the control plane cannot overwrite and instead drops with the request. **What that protects.** Your passphrase and your recovery code are never sent anywhere and are never stored on the cluster. A wrong secret fails in your browser, before anything is submitted. **What it does not protect.** It is the same property that means nobody — Rasputin included — can recover a backup set for you if you lose both secrets. There is no escrow behind this. ## Identity only, and why your app data is left alone Read this before you start; it is the single most misread thing about restore. **Restored — the identity set:** - The control plane's database: your operators, your **passkeys**, your nodes' enrollment tokens, and your app declarations. - The **mesh certificate authority**. - The **mesh state**. **Not restored — your app data.** Every app volume the generation holds stays **sealed on the backup disk**, untouched. The page names them by volume twice: once under the generation you picked, and again in the result. > **IDENTITY ONLY.** This restores the database (users, passkeys, node tokens, app > declarations), the mesh certificate authority and the mesh state. **Why the separation exists.** This is a design decision, not an unfinished feature. A restored control plane is usually standing in front of **nodes that were never wiped**. The machine that died was the control plane; your compute nodes kept running, and the app data on their disks is very likely **newer than anything in any archive**. A restore that automatically pushed archived volumes over them would not be a recovery — it would be automatic data loss, performed without asking you first. **So the second half is a deliberate, per-app, post-login action:** sign in, open **Apps**, select the app, and choose **`RESTORE DATA FROM A BACKUP…`** from its drawer. One app at a time, one generation you pick, with the archive secret asked for again. Nothing restores app data automatically, ever. That flow is documented in [Restoring one app's data](/docs/your-apps/#restoring-one-apps-data). **What you cannot take back — and what you can.** Nothing is written over your live installation when you submit. Everything is extracted into a staging area and verified file by file against the manifest; it moves into place once, at the next start, before any database is opened. The fresh install's own identity files are moved aside rather than deleted, and a restore that fails leaves the machine exactly as it found it. Nothing on the backup disk is modified at any point, so there is no risk in trying again. ## The cluster-id refusal If the archive was written by a cluster with a **different name** than the one this box was flashed with, the page refuses to submit and explains why in full — that the archive's passkeys bind to `.local`, that your nodes dial that name, and that you should re-flash with the original cluster name before restoring. **This is not pedantry about labels.** Your cluster's name is load-bearing in two places the archive cannot reach: - **Your passkeys are bound to `.local`.** A browser will not offer a passkey to a site with a different name, so restored passkeys on a differently-named box are unusable credentials. - **Every node's connection address is derived from it.** Restored node tokens would have your nodes dialling a name that no longer answers. The archive restores credentials and tokens. It cannot restore the hostname — that was written when you flashed the machine. **So the fix is to re-flash the replacement with the original cluster name and come back.** Nothing is wrong with your disk, and refusing is the right outcome: the alternative is a box that half-works, with credentials nothing will offer and nodes calling an address that does not exist. ## If it does not come back — the four-minute deadline The page polls every couple of seconds, waiting for the control plane to come back **reporting operators** — which is the only real proof that the restored database is the one now serving. That is why the wait is not a spinner with a guess on it. It waits four minutes, which is generous on purpose: a restart is seconds, but an appliance with no battery-backed clock can hold its HTTPS listener considerably longer while it settles its time. After four minutes the page says the restore is staged but the control plane has not come back, and that **nothing on the backup disk was changed**. What to do, in order: 1. **Press `RELOAD`.** If the control plane came back while the page was not looking, this finds it. 2. **If the address does not answer at all, power-cycle or restart the machine.** The staged restore is not lost — it applies on the next start, whenever that is. **The backup disk does not need to be attached for that restart**: everything the restore needs was copied off it before the page ever said `RESTORING`. ## Troubleshooting **`Restore is offered only before the first operator is registered`.** A passkey has been registered on this box and the window is closed permanently. Re-flash the control plane, then restore before registering anything. **You cannot find restore in first-run setup.** It is not there and never was. Identity restore lives at `/restore`, reached from the sign-in page — a first-run branch on a replacement machine, not a step of setup. **`No attached disk carries a Rasputin backup set`.** The disk is not attached, not mounted, or is not a Rasputin backup set. Attach it to *this* machine and press `SCAN AGAIN`; restore reads the disk locally. If this cluster's ledger knows about a claimed target that is not attached, the page names it with its last health check rather than showing an empty list — a brand-new replacement has no ledger, so it will not show that. **A disk row says `cannot restore`.** An amber sentence under it says why, and most reasons are terminal for that disk: you pointed at the boot medium; the marker could not be read or names no partition UUID; the disk could not be mounted; the disk's archive key predates the keypair design and this build cannot open its generations; or the disk is a valid backup set whose every generation is unusable. The rows are not clickable, deliberately. **The disk is fine but every generation is unusable.** The reason is in amber on each row. The common one is a re-keyed disk — a generation sealed to a key the disk's marker no longer names, which your current secret cannot open. Others: no identity archive in the generation, a damaged manifest, a manifest written by a newer Rasputin than this image (flash a newer image), or a manifest naming no database, which restores nothing this page puts back. **A generation is badged `incomplete` — can you still use it?** Usually yes. `incomplete` means the run that wrote it did not reach everything it meant to, which mostly concerns app volumes. It is still restorable if it holds the identity set. Note the badge and the headline do not spell it the same way — the badge is lower case and the headline shouts it. **A disk badged `2 generation(s)` shows five rows.** The count is only of generations this build can actually restore from. Section 2 lists the unusable ones as well, with their reasons. **`That does not open this disk's archive key.`** Wrong passphrase or recovery code — and **nothing was sent**, this failed in your browser. Try the other custody path. A recovery code ignores dashes and case, and its alphabet has no `I`, `L`, `O` or `U`; the field strips punctuation and upper-cases what you type but does not reject those letters, so an `O` typed where a `0` belongs still counts toward the 32 and fails here. **`The controlplane refused the key: it does not belong to this disk.`** This is the control plane's check, not the browser's. It re-derives the public key from the key it was handed and compares it with the marker on the disk it actually mounted, so you see this when the key that arrived belongs to a different backup set, or the disk under it is not the one the request named. Restore from the disk the key belongs to. A key mismatch reported during *unlock* is a different fault — there the secret is right and the disk's own records disagree with each other; that one fails in your browser and never reaches the control plane. **`a restore is already prepared and waiting for the api to restart`.** One restore is staged already. Restart the control plane to apply it. One at a time, by design. **`the archive did not pass verification`.** A file in the archive failed its digest or structure check. Nothing was written. Try an older generation. **`restore is not configured on this api`.** This build of the control plane has no restore surface wired. Nothing on this page will help; flash an appliance image. **The page sits in `STILL WAITING`.** The control plane has not come back with operators within four minutes. `RELOAD`, then restart the machine by hand — the restore applies on its next start, with or without the disk attached. **Restored, but an app has no data.** Expected. App volumes are never restored by this page. Restore them per app from the app's drawer in **Apps** — see [Restoring one app's data](/docs/your-apps/#restoring-one-apps-data) — after checking whether the node's own copy is newer, because in many recoveries it is, and the right answer is to restore nothing. **Your old passkey is not offered on the sign-in page.** The cluster name does not match the one the archive was written by. See [The cluster-id refusal](#the-cluster-id-refusal).