From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [IPv6:2a01:7e0:0:424::9]) by lore.proxmox.com (Postfix) with ESMTPS id E86501FF137 for ; Tue, 14 Apr 2026 14:59:17 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 58E651864F; Tue, 14 Apr 2026 14:59:52 +0200 (CEST) From: Christian Ebner To: pbs-devel@lists.proxmox.com Subject: [PATCH proxmox-backup v3 30/30] docs: add section describing server side encryption for sync jobs Date: Tue, 14 Apr 2026 14:59:23 +0200 Message-ID: <20260414125923.892345-31-c.ebner@proxmox.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260414125923.892345-1-c.ebner@proxmox.com> References: <20260414125923.892345-1-c.ebner@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1776171503747 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.070 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Message-ID-Hash: OQ37BDE2LPDNA5OP45GXVLBNBG56TCKB X-Message-ID-Hash: OQ37BDE2LPDNA5OP45GXVLBNBG56TCKB X-MailFrom: c.ebner@proxmox.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list List-Id: Proxmox Backup Server development discussion List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Especially clarify the terminology of active encryption key, associated keys, key archiving and requirements for removal. Signed-off-by: Christian Ebner --- changes since version 2: - not present in previous version docs/managing-remotes.rst | 49 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) diff --git a/docs/managing-remotes.rst b/docs/managing-remotes.rst index 95ac4823c..182fbda09 100644 --- a/docs/managing-remotes.rst +++ b/docs/managing-remotes.rst @@ -302,3 +302,52 @@ The following permissions are required for a sync job in push direction: .. note:: Sync jobs in push direction require namespace support on the remote Proxmox Backup Server instance (minimum version 2.2). + +Server Side Encryption/Decryption During Sync +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Sync job in push direction allow to encrypt unencrypted snapshots when syncing +to a less trusted remote Proxmox Backup Server instance. For this, a server side +encryption key can be assigned to the sync job. This key will then be used to +encrypt the contents before pushing them to the remote, analogous to performing +a backup with an encryption key. Already encrypted snapshots are not re-encrypted +but rather pushed unmodified. Snapshots containing only partially encrypted +contents are skipped for security reasons. + +On the other hand, sync jobs in pull direction allow to assign a number of +associated keys, which will be used to decrypt snapshot contents if the key +fingerprint of one of the listed keys matches the one used to encrypt the +backup snapshot. The active encryption key has no effect for sync jobs in pull +direction and should not be set. + +In order to configure the sync job, as well as for sync job owner/local user +to access the keys during sync, ``System.Modify`` permissions are required on +the ``/system/encryption-keys/{key}`` path. + +.. note:: Encryption key handling comes with a few risks, especially with key + rotatiton. Therefore, only active keys can be used to encrypt new snapshot + contents during push sync. If an active encryption key is changed, the key is + kept back as associated key on the sync job, in order to protect it from + accidental removal. Further, any encryption key can be archived, rendering it + no longer usable for encryption, only to decrypt pre-existing contents. Any + encryption key usable for sync jobs must therefore be marked as archived and + disassociated from any sync job still associated to it, before being able to + remove it. + +The following command can be used to assign the active encryption key for a sync +job. + +.. code-block:: console + + # proxmox-backup-manager sync-job update pbs2-push --active-encryption-key key0 + +Setting the associated keys will drop any key not present in the given key list, +with exception of the previously assigned active encryption key, if it is updated +as well. The previously assigned encryption key will always be pushed to the list +of associated keys on rotation. For example, below command would assign ``key`` +as the new active encryption key and ``key0,key2,key3`` as associated keys for +the sync job. + +.. code-block:: console + + # proxmox-backup-manager sync-job update pbs2-push --active-encryption-key key1 --associated-key key2 --associated-key key3 -- 2.47.3