Merge pull request #6512 from BulaYoungR/snapshot_memonly

Create external memory only snapshot

Author: dzhengfy

libvirt/tests/cfg/snapshot/virsh_memonly_snapshot.cfg

@@ -0,0 +1,6 @@
+- virsh_memonly_snapshot:
+    type = virsh_memonly_snapshot
+    start_vm = yes
+    variants scenario:
+        - xml_diskspec:
+        - cli_diskspec:

libvirt/tests/src/snapshot/virsh_memonly_snapshot.py

@@ -0,0 +1,96 @@
+# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+#
+#   virsh_memonly_snapshot.py
+#
+#   SPDX-License-Identifier: GPL-2.0
+#
+# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+"""
+Avocado-VT test: create a *memory-only* snapshot for a running guest.
+
+Two scenarios are supported:
+  - xml_diskspec: set <disk snapshot='no'> in domain XML for all disks
+  - cli_diskspec: leave XML intact, pass --diskspec <dev>,snapshot=no via CLI
+
+If 'mem_file' is not provided, the test will create a unique path in tmp.
+"""
+
+import time
+from pathlib import Path
+
+from virttest import virsh, data_dir
+from virttest.libvirt_xml import vm_xml
+from virttest.utils_libvirt import libvirt_vmxml, libvirt_disk
+
+
+def run(test, params, env):
+    """
+    Entry point for Avocado-VT.
+
+    Params (from .cfg):
+        main_vm:      VM name under test (required)
+        scenario:     'xml_diskspec' (default) or 'cli_diskspec'
+        mem_file:     Optional path to store memory dump created by --memspec
+
+    The test ensures the VM is running, applies disk snapshot=no either via
+    XML or CLI, then runs:
+        virsh snapshot-create-as --no-metadata --memspec file=<mem> --live
+    Finally, it restores the original domain XML.
+    """
+    vm_name = params.get("main_vm")
+    if not vm_name:
+        test.error("Missing 'main_vm'")
+
+    default_mem = Path(data_dir.get_tmp_dir()) / f"{vm_name}-{int(time.time())}.mem"
+    mem_file = Path(params.get("mem_file", str(default_mem)))
+
+    case = params.get("scenario", "")
+    cli_diskspec = case == "cli_diskspec"
+
+    vm = env.get_vm(vm_name)
+    if vm is None:
+        test.error(f"VM '{vm_name}' not found")
+
+    backup_xml = None
+    disk_targets = []
+
+    def _ensure_running():
+        """Start the VM if it is not already running."""
+        if not vm.is_alive():
+            vm.start()
+
+    def _snapshot_create():
+        """Invoke virsh to create a live memory-only snapshot."""
+        mem_file.parent.mkdir(parents=True, exist_ok=True)
+        opts = f"--no-metadata --memspec file={mem_file} --live"
+        if cli_diskspec:
+            for dev in disk_targets:
+                opts += f" --diskspec {dev},snapshot=no"
+        virsh.snapshot_create_as(vm_name, options=opts, ignore_status=False, debug=True)
+
+    def setup_test():
+        """Backup XML, collect disk targets and prepare the scenario."""
+        nonlocal backup_xml, disk_targets
+        backup_xml = vm_xml.VMXML.new_from_inactive_dumpxml(vm_name)
+        disk_targets = libvirt_disk.all_disk_targets(vm_name)
+        test.log.debug(f"scenario: {case}")
+        test.log.debug(f"mem_file: {mem_file}")
+        test.log.debug(f"disk_targets: {disk_targets}")
+        if not cli_diskspec:
+            vmx = vm_xml.VMXML.new_from_inactive_dumpxml(vm_name)
+            for dev in disk_targets:
+                disk_dict = {"target": {"dev": dev}, "snapshot": "no"}
+                libvirt_vmxml.modify_vm_device(vmx, "disk", disk_dict)
+            test.log.debug(vm_xml.VMXML.new_from_inactive_dumpxml(vm_name))
+        _ensure_running()
+
+    def teardown_test():
+        """Restore original domain XML (and implicit cleanup)."""
+        if backup_xml is not None:
+            backup_xml.sync()
+
+    try:
+        setup_test()
+        _snapshot_create()
+    finally:
+        teardown_test()