test: remove snapshot forward-compatibility tests

We dropped support for Firecracker snapshots forward compatibility.
Clean up the tests related to this functionality. Mainly remove tests
that directly use the removed feature and re-organize some of the code
to adapt to the now missing functionality.

Signed-off-by: Babis Chalios <bchalios@amazon.es>

tests/framework/artifacts.py

@@ -125,6 +125,14 @@ def current_release(version):
     return binaries
 
 
+def working_version_as_artifact():
+    """
+    Return working copy of Firecracker as a release artifact
+    """
+    cargo_version = get_firecracker_version_from_toml()
+    return FirecrackerArtifact(current_release(cargo_version.base_version)[0])
+
+
 def firecracker_artifacts():
     """Return all supported firecracker binaries."""
     cargo_version = get_firecracker_version_from_toml()
@@ -141,7 +149,7 @@ def firecracker_artifacts():
             continue
         yield pytest.param(fc, id=fc.name)
 
-    fc = FirecrackerArtifact(current_release(cargo_version.base_version)[0])
+    fc = working_version_as_artifact()
     yield pytest.param(fc, id=fc.name)
 
 

tests/framework/microvm.py

@@ -710,9 +710,7 @@ def resume(self):
         """Resume the microVM"""
         self.api.vm.patch(state="Resumed")
 
-    def make_snapshot(
-        self, snapshot_type: SnapshotType | str, target_version: str = None
-    ):
+    def make_snapshot(self, snapshot_type: SnapshotType | str):
         """Create a Snapshot object from a microvm.
 
         It pauses the microvm before taking the snapshot.
@@ -725,7 +723,6 @@ def make_snapshot(
             mem_file_path=str(mem_path),
             snapshot_path=str(vmstate_path),
             snapshot_type=snapshot_type.value,
-            version=target_version,
         )
         root = Path(self.chroot())
         return Snapshot(
@@ -737,13 +734,13 @@ def make_snapshot(
             snapshot_type=snapshot_type,
         )
 
-    def snapshot_diff(self, target_version: str = None):
+    def snapshot_diff(self):
         """Make a Diff snapshot"""
-        return self.make_snapshot("Diff", target_version)
+        return self.make_snapshot("Diff")
 
-    def snapshot_full(self, target_version: str = None):
+    def snapshot_full(self):
         """Make a Full snapshot"""
-        return self.make_snapshot("Full", target_version)
+        return self.make_snapshot("Full")
 
     def restore_from_snapshot(
         self,

tests/integration_tests/functional/test_api.py

@@ -1291,28 +1291,6 @@ def test_map_private_seccomp_regression(test_microvm_with_api):
     test_microvm.api.mmds.put(**data_store)
 
 
-def test_negative_snapshot_create_api(microvm_factory, guest_kernel, rootfs):
-    """
-    Test snapshot create API.
-    """
-
-    vm = microvm_factory.build(guest_kernel, rootfs)
-    vm.spawn()
-    vm.basic_config()
-    vm.start()
-
-    # Specifying `version` in the create API is deprecated
-    vm.pause()
-    response = vm.api.snapshot_create.put(
-        mem_file_path="mem",
-        snapshot_path="vmstate",
-        snapshot_type="Full",
-        version="1.4.0",
-    )
-    assert response.headers["deprecation"]
-    assert "PUT /snapshot/create: 'version' field is deprecated." in vm.log_data
-
-
 # pylint: disable=protected-access
 def test_negative_snapshot_load_api(microvm_factory):
     """

tests/integration_tests/functional/test_drives.py

@@ -361,46 +361,6 @@ def test_flush(uvm_plain_rw):
     assert fc_metrics["block"]["flush_count"] > 0
 
 
-def test_block_default_cache_old_version(test_microvm_with_api):
-    """
-    Verify that saving a snapshot for old versions works correctly.
-    """
-    test_microvm = test_microvm_with_api
-    test_microvm.spawn()
-
-    test_microvm.basic_config(vcpu_count=1, add_root_device=False)
-
-    # Add the block device with explicitly enabling flush.
-    test_microvm.add_drive(
-        "rootfs",
-        test_microvm.rootfs_file,
-        is_root_device=True,
-        cache_type="Writeback",
-    )
-
-    test_microvm.start()
-
-    # Pause the VM to create the snapshot.
-    test_microvm.pause()
-
-    # Create the snapshot for a version without block cache type.
-    test_microvm.api.snapshot_create.put(
-        mem_file_path="memfile",
-        snapshot_path="snapsfile",
-        snapshot_type="Full",
-        version="0.24.0",
-    )
-
-    # We should find a warning in the logs for this case as this
-    # cache type was not supported in 0.24.0 and we should default
-    # to "Unsafe" mode.
-    test_microvm.check_log_message(
-        "Target version does not implement the"
-        " current cache type. "
-        'Defaulting to "unsafe" mode.'
-    )
-
-
 def _check_block_size(ssh_connection, dev_path, size):
     _, stdout, stderr = ssh_connection.run("blockdev --getsize64 {}".format(dev_path))
     assert stderr == ""

tests/integration_tests/functional/test_mmds.py

@@ -9,6 +9,7 @@
 
 import pytest
 
+from framework.artifacts import working_version_as_artifact
 from framework.properties import global_props
 from framework.utils import (
     configure_mmds,
@@ -33,7 +34,6 @@ def _validate_mmds_snapshot(
     basevm,
     microvm_factory,
     version,
-    target_fc_version=None,
     fc_binary_path=None,
     jailer_binary_path=None,
 ):
@@ -76,7 +76,7 @@ def _validate_mmds_snapshot(
     run_guest_cmd(ssh_connection, cmd, data_store, use_json=True)
 
     # Create snapshot.
-    snapshot = basevm.snapshot_full(target_version=target_fc_version)
+    snapshot = basevm.snapshot_full()
 
     # Resume microVM and ensure session token is still valid on the base.
     response = basevm.resume()
@@ -591,22 +591,22 @@ def test_mmds_limit_scenario(test_microvm_with_api, version):
 
 
 @pytest.mark.parametrize("version", MMDS_VERSIONS)
-def test_mmds_snapshot(uvm_nano, microvm_factory, version, firecracker_release):
+def test_mmds_snapshot(uvm_nano, microvm_factory, version):
     """
     Test MMDS behavior by restoring a snapshot on current FC versions.
 
     Ensures that the version is persisted or initialised with the default if
     the firecracker version does not support it.
     """
 
+    current_release = working_version_as_artifact()
     uvm_nano.add_net_iface()
     _validate_mmds_snapshot(
         uvm_nano,
         microvm_factory,
         version,
-        target_fc_version=firecracker_release.snapshot_version,
-        fc_binary_path=firecracker_release.path,
-        jailer_binary_path=firecracker_release.jailer,
+        fc_binary_path=current_release.path,
+        jailer_binary_path=current_release.jailer,
     )
 
 
@@ -640,7 +640,6 @@ def test_mmds_older_snapshot(
         microvm,
         microvm_factory,
         mmds_version,
-        firecracker_release.snapshot_version,
         *get_firecracker_binaries(),
     )
 

tests/integration_tests/functional/test_snapshot_advanced.py

@@ -2,7 +2,6 @@
 # SPDX-License-Identifier: Apache-2.0
 """Advanced tests scenarios for snapshot save/restore."""
 
-import platform
 import tempfile
 
 import pytest
@@ -55,51 +54,6 @@ def test_restore_old_to_current(
     print(vm.log_data)
 
 
-def test_restore_current_to_old(microvm_factory, uvm_plain, firecracker_release):
-    """
-    Restore current snapshot with previous versions of Firecracker.
-
-    For each firecracker release:
-    1. Snapshot with the current build
-    2. Restore with the past release
-    """
-
-    # Microvm: 2vCPU 256MB RAM, balloon, 4 disks and 4 net devices.
-    vm = uvm_plain
-    vm.spawn()
-    vm.basic_config(track_dirty_pages=True)
-
-    # Create a snapshot with current FC version targeting the old version.
-    snapshot = create_snapshot_helper(
-        vm,
-        target_version=firecracker_release.snapshot_version,
-        drives=scratch_drives,
-        balloon=True,
-        diff_snapshots=True,
-    )
-
-    # Resume microvm using FC/Jailer binary artifacts.
-    vm = microvm_factory.build(
-        fc_binary_path=firecracker_release.path,
-        jailer_binary_path=firecracker_release.jailer,
-    )
-    vm.spawn()
-    vm.restore_from_snapshot(snapshot, resume=True)
-    validate_all_devices(vm, True)
-    print("========== Firecracker restore snapshot log ==========")
-    print(vm.log_data)
-
-
-@pytest.mark.skipif(platform.machine() != "x86_64", reason="TSC is x86_64 specific.")
-def test_save_tsc_old_version(uvm_nano):
-    """
-    Test TSC warning message when saving old snapshot.
-    """
-    uvm_nano.start()
-    uvm_nano.snapshot_full(target_version="0.24.0")
-    uvm_nano.check_log_message("Saving to older snapshot version, TSC freq")
-
-
 def validate_all_devices(microvm, balloon):
     """Perform a basic validation for all devices of a microvm."""
     # Test that net devices have connectivity after restore.
@@ -139,7 +93,6 @@ def validate_all_devices(microvm, balloon):
 
 def create_snapshot_helper(
     vm,
-    target_version=None,
     drives=None,
     balloon=False,
     diff_snapshots=False,
@@ -196,7 +149,7 @@ def create_snapshot_helper(
         exit_code, _, _ = vm.ssh.run(cmd)
         assert exit_code == 0
 
-    snapshot = vm.make_snapshot(snapshot_type, target_version=target_version)
+    snapshot = vm.make_snapshot(snapshot_type)
     print("========== Firecracker create snapshot log ==========")
     print(vm.log_data)
     vm.kill()

tests/integration_tests/functional/test_snapshot_basic.py

@@ -12,7 +12,12 @@
 
 import host_tools.drive as drive_tools
 from framework.microvm import SnapshotType
-from framework.utils import check_filesystem, wait_process_termination
+from framework.utils import (
+    check_filesystem,
+    get_firecracker_version_from_toml,
+    run_cmd,
+    wait_process_termination,
+)
 from framework.utils_vsock import (
     ECHO_SERVER_PORT,
     VSOCK_UDS_PATH,
@@ -23,6 +28,7 @@
     make_host_port_path,
     start_guest_echo_server,
 )
+from host_tools.cargo_build import get_firecracker_binaries
 
 
 def _get_guest_drive_size(ssh_connection, guest_dev_name="/dev/vdb"):
@@ -35,6 +41,32 @@ def _get_guest_drive_size(ssh_connection, guest_dev_name="/dev/vdb"):
     return lines[1].strip()
 
 
+def test_snapshot_current_version(uvm_nano):
+    """Tests taking a snapshot at the version specified in Cargo.toml
+
+    Check that it is possible to take a snapshot at the version of the upcoming
+    release (during the release process this ensures that if we release version
+    x.y, then taking a snapshot at version x.y works - something we'd otherwise
+    only be able to test once the x.y binary has been uploaded to S3, at which
+    point it is too late, see also the 1.3 release).
+    """
+    vm = uvm_nano
+    vm.start()
+
+    version = get_firecracker_version_from_toml()
+    # normalize to a snapshot version
+    version = f"{version.major}.{version.minor}.0"
+    snapshot = vm.snapshot_full()
+
+    # Fetch Firecracker binary for the latest version
+    fc_binary, _ = get_firecracker_binaries()
+    # Verify the output of `--describe-snapshot` command line parameter
+    cmd = [str(fc_binary)] + ["--describe-snapshot", str(snapshot.vmstate)]
+
+    _, stdout, _ = run_cmd(cmd)
+    assert version in stdout
+
+
 # Testing matrix:
 # - Guest kernel: All supported ones
 # - Rootfs: Ubuntu 18.04