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Version: Next

Backup and restore

When: on the database's schedule; before an upgrade; a restore after a loss, a corruption or a failed upgrade.

Who: the platform operator, with the database's and the KEK's administrators.

What to back up​

The store holds everything but the KEK. Material in it is sealed: without the KEK it does not open.

  • The database (SQLite, PostgreSQL, SQL Server): as any database. It holds the secrets, variables, grants, delegation grants and the wrapped data keys.
    • The installation id (the installation table, made by the migration) is in every MAC of a SQL store. Keep it with the backups: lost, every row is refused, and the service never makes a new one.
  • The Kubernetes store: the namespace's tresor resources (kubectl get tresor), with Velero or the cluster's backup. state.instance (the namespace by default) is in every MAC: keep it stable, and restore into the same namespace, or set state.instance to the old one.
  • The KEK, as carefully as the backups:
    • Key Vault: purge protection on, and every version a backup's data keys name;
    • Vault Transit: Vault's own backup. The key is never exportable (the service refuses such a key);
    • AWS KMS, GCP Cloud KMS: both keys, and every version a backup's data keys name;
    • a local key: its value, apart from the database's backups.
  • The configuration: the chart's values, the recipe's parameters, the file. The KEK's settings name the key.

A backup holds its own data keys. A data key retired since, or a leaked one, still opens it.

Restore​

  1. Stop the service (Kubernetes: kubectl -n tresor scale deploy/<fullname> --replicas=0).

  2. Restore the store:

    • a database: as any database, with its installation table;

    • the Kubernetes store: the CRDs first (helm pull oci://ghcr.io/hugr-lab/charts/tresor-server --version <version> --untar && kubectl apply --server-side -f tresor-server/crds/, the release's chart version). A restore (Velero) writes as another account than the service's: remove the admission policy's binding for its duration (step 4 puts it back).

      kubectl delete validatingadmissionpolicybinding <fullname>-<namespace>
      # the restore

  3. The same KEK and configuration as when the backup was taken - any previous KEK its data keys are under in keys.previous. The same version of the service, or a newer one: an older one refuses a database a newer one migrated.

  4. Start the service: on Kubernetes, helm upgrade with the release's values and chart version - it puts the admission policy's binding back and scales the Deployment to its replicas (not before step 3: Helm restores the replicas a manual scale set to 0).

    helm upgrade <release> oci://ghcr.io/hugr-lab/charts/tresor-server --version <the release's chart version> \
      -n tresor -f values.yaml

Check​

  • Readiness: state and keys are ok. On the Kubernetes store, a wrong KEK or instance is not ready (the installation's mark does not verify).
  • A read: a secret reads through the protocol, or the console.
  • refs exits 0: the references resolve with the configuration.
  • The console's Service screen: the store, the KEK, the data keys.
  • The log: no row refused (tresor.state.left_out at 0, Observability). Minted tokens are minted again.

Back​

Restore again from another backup; the restore replaced the store. What was written after the backup is lost: grants revoked since are back, secrets deleted since are back. Check them with the secrets administrators.