Fix start error in load_persistent_executions (#759)

* Fix start error in  load_persistent_executions

Fix parse error that prevented Supervisor from starting when loading
persistant executions, as it could not parse the gpu field

    Traceback (most recent call last):
      File "/usr/lib/python3.10/runpy.py", line 196, in _run_module_as_main
        return _run_code(code, main_globals, None,
      File "/usr/lib/python3.10/runpy.py", line 86, in _run_code
        exec(code, run_globals)
      File "/opt/aleph-vm/aleph/vm/orchestrator/__main__.py", line 4, in <module>
        main()
      File "/opt/aleph-vm/aleph/vm/orchestrator/cli.py", line 379, in main
        supervisor.run()
      File "/opt/aleph-vm/aleph/vm/orchestrator/supervisor.py", line 184, in run
        asyncio.run(pool.load_persistent_executions())
      File "/usr/lib/python3.10/asyncio/runners.py", line 44, in run
        return loop.run_until_complete(main)
      File "/usr/lib/python3.10/asyncio/base_events.py", line 649, in run_until_complete
        return future.result()
      File "/opt/aleph-vm/aleph/vm/pool.py", line 252, in load_persistent_executions
        execution.gpus = parse_raw_as(List[HostGPU], saved_execution.gpus)
      File "pydantic/tools.py", line 74, in pydantic.tools.parse_raw_as
        obj = load_str_bytes(
      File "pydantic/parse.py", line 37, in pydantic.parse.load_str_bytes
        return json_loads(b)
      File "/usr/lib/python3.10/json/__init__.py", line 339, in loads
        raise TypeError(f'the JSON object must be str, bytes or bytearray, '
    TypeError: the JSON object must be str, bytes or bytearray, not NoneType

* Fix packaging issue caused by sevctl

Author: olethanh

packaging/Makefile

@@ -48,7 +48,7 @@ download-ipfs-kubo: target-dir build-dir
 	curl -fsSL https://github.com/ipfs/kubo/releases/download/v0.23.0/kubo_v0.23.0_linux-amd64.tar.gz | tar -xz --directory ./target/kubo
 
 target/bin/sevctl:
-	cargo install --git https://github.com/virtee/sevctl.git --rev v0.6.0 --target x86_64-unknown-linux-gnu --root ./target
+	cargo install --locked --git https://github.com/virtee/sevctl.git --rev v0.6.0 --target x86_64-unknown-linux-gnu --root ./target
 	./target/bin/sevctl -V
 
 version:

src/aleph/vm/pool.py

@@ -249,7 +249,7 @@ async def load_persistent_executions(self):
             if execution.is_running:
                 # TODO: Improve the way that we re-create running execution
                 # Load existing GPUs assigned to VMs
-                execution.gpus = parse_raw_as(List[HostGPU], saved_execution.gpus)
+                execution.gpus = parse_raw_as(List[HostGPU], saved_execution.gpus) if saved_execution.gpus else []
                 # Load and instantiate the rest of resources and already assigned GPUs
                 await execution.prepare()
                 if self.network: