NAS backup: support incremental backups of RBD volumes

api/src/main/java/com/cloud/host/Host.java

@@ -58,6 +58,7 @@ public static String[] toStrings(Host.Type... types) {
     String HOST_KVM_DISK_ONLY_VM_SNAPSHOT_NVRAM = "host.kvm.diskonlyvmsnapshot.nvram";
     String HOST_VOLUME_ENCRYPTION = "host.volume.encryption";
     String HOST_RBD_VOLUME_ENCRYPTION = "host.volume.encryption.rbd";
+    String HOST_RBD_CLI = "host.rbd.cli";
     String HOST_INSTANCE_CONVERSION = "host.instance.conversion";
     String HOST_VDDK_SUPPORT = "host.vddk.support";
     String HOST_VDDK_LIB_DIR = "vddk.lib.dir";

core/src/main/java/org/apache/cloudstack/backup/RemoveBackupAnchorsCommand.java

@@ -0,0 +1,64 @@
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+//
+
+package org.apache.cloudstack.backup;
+
+import java.util.List;
+
+import org.apache.cloudstack.storage.to.PrimaryDataStoreTO;
+
+import com.cloud.agent.api.Command;
+
+/**
+ * Remove the backup anchors of an Instance's volumes: the RBD snapshots an incremental chain is
+ * exported from. An anchor is only kept to export the next incremental from it, so once the chain
+ * is gone the next backup is a full one and the anchor would only keep the data it references
+ * allocated in the pool.
+ */
+public class RemoveBackupAnchorsCommand extends Command {
+    private List<PrimaryDataStoreTO> volumePools;
+    private List<String> volumePaths;
+
+    public RemoveBackupAnchorsCommand(List<PrimaryDataStoreTO> volumePools, List<String> volumePaths) {
+        super();
+        this.volumePools = volumePools;
+        this.volumePaths = volumePaths;
+    }
+
+    public List<PrimaryDataStoreTO> getVolumePools() {
+        return volumePools;
+    }
+
+    public void setVolumePools(List<PrimaryDataStoreTO> volumePools) {
+        this.volumePools = volumePools;
+    }
+
+    public List<String> getVolumePaths() {
+        return volumePaths;
+    }
+
+    public void setVolumePaths(List<String> volumePaths) {
+        this.volumePaths = volumePaths;
+    }
+
+    @Override
+    public boolean executeInSequence() {
+        return true;
+    }
+}

core/src/main/java/org/apache/cloudstack/backup/RestoreBackupCommand.java

@@ -41,6 +41,22 @@ public class RestoreBackupCommand extends Command  {
     private VirtualMachine.State vmState;
     private Integer mountTimeout;
 
+    /**
+     * On-NAS format of the backup files: {@code qcow2} (default, also when null) or {@code rbddiff}
+     * for Ceph/RBD chains written with {@code rbd export-diff}. Decides both the file extension the
+     * agent looks for and how the volume is reconstructed.
+     */
+    private String backupFormat;
+
+    /**
+     * For {@code rbddiff} backups: every backup directory of the chain from its full anchor up to
+     * and including the backup being restored, ordered root-first. {@code rbd import-diff} streams
+     * have no backing-file metadata, so the chain cannot be self-describing the way rebased qcow2
+     * files are — the agent has to be told which diffs to replay and in which order. Null/empty for
+     * qcow2 backups.
+     */
+    private List<String> backupChainPaths;
+
     protected RestoreBackupCommand() {
         super();
     }
@@ -164,4 +180,20 @@ public Integer getMountTimeout() {
     public void setMountTimeout(Integer mountTimeout) {
         this.mountTimeout = mountTimeout;
     }
+
+    public String getBackupFormat() {
+        return backupFormat;
+    }
+
+    public void setBackupFormat(String backupFormat) {
+        this.backupFormat = backupFormat;
+    }
+
+    public List<String> getBackupChainPaths() {
+        return backupChainPaths;
+    }
+
+    public void setBackupChainPaths(List<String> backupChainPaths) {
+        this.backupChainPaths = backupChainPaths;
+    }
 }

core/src/main/java/org/apache/cloudstack/backup/TakeBackupCommand.java

@@ -39,6 +39,7 @@ public class TakeBackupCommand extends Command {
 
     // Incremental backup fields (NAS provider; null/empty for legacy full-only callers).
     private String mode;          // "full" or "incremental"; null => legacy behaviour (script default)
+    private String method;        // "qcow2" (bitmaps, push mode), "content" (pull mode) or "rbd" (Ceph export-diff); null => "qcow2"
     private String bitmapNew;     // Checkpoint/bitmap name to create with this backup (timestamp-based)
     private String bitmapParent;  // Incremental: parent bitmap to read changes since
 
@@ -134,6 +135,14 @@ public void setMode(String mode) {
         this.mode = mode;
     }
 
+    public String getMethod() {
+        return method;
+    }
+
+    public void setMethod(String method) {
+        this.method = method;
+    }
+
     public String getBitmapNew() {
         return bitmapNew;
     }

debian/control

@@ -26,6 +26,7 @@ Package: cloudstack-agent
 Architecture: all
 Depends: ${python:Depends}, ${python3:Depends}, openjdk-17-jre-headless | java17-runtime-headless | java17-runtime | zulu-17, cloudstack-common (= ${source:Version}), lsb-base (>= 9), openssh-client, qemu-kvm (>= 2.5) | qemu-system-x86 (>= 5.2), libvirt-bin (>= 1.3) | libvirt-daemon-system (>= 3.0), iproute2, ebtables, vlan, ipset, python3-libvirt, ethtool, iptables, cryptsetup, rng-tools, rsync, ovmf, swtpm, lsb-release, ufw, apparmor, cpu-checker, libvirt-daemon-driver-storage-rbd, sysstat, python3-libnbd, socat
 Recommends: init-system-helpers
+Suggests: ceph-common
 Conflicts: cloud-agent, cloud-agent-libs, cloud-agent-deps, cloud-agent-scripts
 Description: CloudStack agent
  The CloudStack agent is in charge of managing shared computing resources in

packaging/el8/cloud.spec

@@ -128,6 +128,7 @@ Requires: (libgcrypt > 1.8.3 or libgcrypt20)
 Requires: (selinux-tools if selinux-tools)
 Requires: sysstat
 Requires: python3-libnbd
+Suggests: ceph-common
 Requires: socat
 Provides: cloud-agent
 Group: System Environment/Libraries

packaging/suse15/cloud.spec

@@ -120,6 +120,7 @@ Requires: cifs-utils
 Requires: (edk2-ovmf or qemu-ovmf-x86_64)
 Requires: swtpm
 Requires: (python3-libvirt or python3-libvirt-python)
+Suggests: ceph-common
 Requires: (qemu-img or qemu-tools)
 Requires: qemu-kvm
 Requires: cryptsetup

plugins/backup/nas/src/main/java/org/apache/cloudstack/backup/NASBackupChainKeys.java

@@ -27,9 +27,21 @@ public final class NASBackupChainKeys {
     /** UUID of the parent backup (full or previous incremental). Empty for full backups. */
     public static final String PARENT_BACKUP_ID = "nas.parent_backup_id";
 
-    /** QEMU dirty-bitmap name created by this backup, used as the {@code <incremental>} reference for the next one. */
+    /**
+     * Name of the point-in-time anchor this backup created, used as the parent reference for the
+     * next backup in the chain. Its meaning depends on the chain format: for {@link #FORMAT_QCOW2}
+     * chains it is the QEMU dirty-bitmap name used as the {@code <incremental>} reference; for
+     * {@link #FORMAT_RBD_DIFF} chains it is the RBD snapshot name used as {@code --from-snap}.
+     */
     public static final String BITMAP_NAME = "nas.bitmap_name";
 
+    /**
+     * On-NAS format of the chain this backup belongs to: {@link #FORMAT_QCOW2} (rebased qcow2
+     * files, the file-based storage path) or {@link #FORMAT_RBD_DIFF} ({@code rbd export-diff}
+     * streams, the Ceph/RBD path). Absent on legacy-full backups, which are always qcow2.
+     */
+    public static final String CHAIN_FORMAT = "nas.chain_format";
+
     /** Identifier shared by every backup in the same chain (the full anchors a chain; its incrementals inherit the id). */
     public static final String CHAIN_ID = "nas.chain_id";
 
@@ -48,6 +60,31 @@ public final class NASBackupChainKeys {
     // "legacy-full" mode token (which sets make_checkpoint=0).
     public static final String TYPE_LEGACY_FULL = "legacy-full";
 
+    /**
+     * In-memory backup-method sentinels used by {@code ChainDecision.method}: how a backup is
+     * taken, independent of whether it is a full or an incremental ({@code ChainDecision.mode}).
+     *
+     * <p>{@link #METHOD_QCOW2}: libvirt push-mode backup; incrementals come from QEMU persistent
+     * dirty bitmaps (libvirt checkpoints), which only qcow2 volumes can carry.</p>
+     */
+    public static final String METHOD_QCOW2 = "qcow2";
+
+    /**
+     * Content-based libvirt pull-mode backup, used for raw block-device storage such as
+     * LINSTOR/DRBD which cannot carry persistent dirty bitmaps. A full is written as a sparse
+     * qcow2 in a single pass; an incremental is a qcow2 overlay on the disk's NBD export,
+     * safe-rebased onto the parent so it holds only the clusters that differ.
+     */
+    public static final String METHOD_CONTENT = "content";
+
+    /**
+     * Ceph-native backup, used for RBD volumes. They are raw and cannot carry a persistent dirty
+     * bitmap, so each cycle anchors on an RBD snapshot and exports the delta with
+     * {@code rbd export-diff}. Unlike the other methods this one writes {@link #FORMAT_RBD_DIFF}
+     * streams rather than qcow2 files, which is what {@link #CHAIN_FORMAT} records for restore.
+     */
+    public static final String METHOD_RBD = "rbd";
+
     /**
      * VM-scoped detail (stored in {@code vm_instance_details}) holding the QEMU dirty-bitmap
      * name that currently exists on the running VM and is therefore the only valid parent
@@ -57,6 +94,10 @@ public final class NASBackupChainKeys {
      */
     public static final String VM_ACTIVE_CHECKPOINT_ID = "nas.active_checkpoint_id";
 
+    /** Chain format values persisted under {@link #CHAIN_FORMAT}; also the on-NAS file extension. */
+    public static final String FORMAT_QCOW2 = "qcow2";
+    public static final String FORMAT_RBD_DIFF = "rbddiff";
+
     private NASBackupChainKeys() {
     }
 }