ch_tests: dynamically determine data disk path

The test VM undergoes a reboot during preparation for CH community
tests, causing the device path for the data disk to potentially change.
So, data disk device path is now determined dynamically just before
launching the CH tests, eliminating the need for 'datadisk_name' test
input variable.

microsoft/testsuites/cloud_hypervisor/ch_tests.py

@@ -206,7 +206,6 @@ def _set_ms_clh_param(self, variables: Dict[str, Any]) -> None:
         # will not run it with data-disk and it would not add direct=on
         # if run_without_cache is not set to YES
         use_datadisk = variables.get("use_datadisk", "")
-        datadisk_name = variables.get("datadisk_name", "")
         disable_datadisk_cache = variables.get("disable_datadisk_cache", "")
         block_size_kb = variables.get("block_size_kb", "")
 
@@ -232,8 +231,6 @@ def _set_ms_clh_param(self, variables: Dict[str, Any]) -> None:
             CloudHypervisorTests.block_size_kb = block_size_kb
         if use_datadisk:
             CloudHypervisorTests.use_datadisk = use_datadisk
-        if datadisk_name:
-            CloudHypervisorTests.datadisk_name = datadisk_name
         if disable_datadisk_cache:
             CloudHypervisorTests.disable_datadisk_cache = disable_datadisk_cache
 

microsoft/testsuites/cloud_hypervisor/ch_tests_tool.py

@@ -22,11 +22,12 @@
     Echo,
     Git,
     Ls,
+    Lsblk,
     Mkdir,
     Modprobe,
     Whoami,
 )
-from lisa.util import find_groups_in_lines
+from lisa.util import LisaException, find_groups_in_lines
 
 
 @dataclass
@@ -62,7 +63,6 @@ class CloudHypervisorTests(Tool):
 
     # Block perf related env var
     use_datadisk = ""
-    datadisk_name = ""
     disable_datadisk_cache = ""
     block_size_kb = ""
 
@@ -164,6 +164,9 @@ def run_metrics_tests(
         skip: Optional[List[str]] = None,
         subtest_timeout: Optional[int] = None,
     ) -> None:
+        if self.use_datadisk:
+            self._set_data_disk()
+
         if ref:
             self.node.tools[Git].checkout(ref, self.repo_root)
 
@@ -264,8 +267,6 @@ def _install(self) -> bool:
 
             if self.use_datadisk:
                 self.env_vars["USE_DATADISK"] = self.use_datadisk
-            if self.datadisk_name:
-                self.env_vars["DATADISK_NAME"] = self.datadisk_name
             if self.disable_datadisk_cache:
                 self.env_vars["DISABLE_DATADISK_CACHING"] = self.disable_datadisk_cache
             if self.block_size_kb:
@@ -496,6 +497,23 @@ def _configure_vdpa_devices(self, node: Node) -> None:
             node.tools[Chown].change_owner(file=PurePath(device_path), user=user)
             node.tools[Chmod].chmod(path=device_path, permission=permission, sudo=True)
 
+    def _set_data_disk(self) -> None:
+        datadisk_name = ""
+        disks = self.node.tools[Lsblk].get_disks()
+        # get the first unmounted disk (data disk)
+        for disk in disks:
+            if disk.is_mounted:
+                continue
+            if disk.name.startswith("sd"):
+                datadisk_name = disk.device_name
+                break
+        # running lsblk once again, just for human readable logs
+        self.node.execute("lsblk", shell=True)
+        if not datadisk_name:
+            raise LisaException("No data disk found")
+        self._log.debug(f"Using data disk: {datadisk_name}")
+        self.env_vars["DATADISK_NAME"] = datadisk_name
+
 
 def extract_jsons(input_string: str) -> List[Any]:
     json_results: List[Any] = []