fix: restore the id parameter default

src/firecracker/src/main.rs

@@ -144,6 +144,7 @@
             .arg(
                 Argument::new("id")
                     .takes_value(true)
+                    .default_value(vmm::logger::DEFAULT_INSTANCE_ID)
                     .help("MicroVM unique identifier."),
             )
             .arg(
@@ -262,8 +263,6 @@
         return Ok(());
     }
 
-    info!("Running Firecracker v{FIRECRACKER_VERSION}");
-
     register_signal_handlers().map_err(MainError::RegisterSignalHandlers)?;
 
     #[cfg(target_arch = "aarch64")]
@@ -298,11 +297,9 @@
         app_name: "Firecracker".to_string(),
     };
 
-    let id = arguments
-        .single_value("id")
-        .map(|s| s.as_str())
-        .unwrap_or(vmm::logger::DEFAULT_INSTANCE_ID);
+    let id = arguments.single_value("id").map(|s| s.as_str()).unwrap();
     vmm::logger::INSTANCE_ID.set(String::from(id)).unwrap();
+    info!("Running Firecracker v{FIRECRACKER_VERSION}");
 
     // Apply the logger configuration.
     let log_path = arguments.single_value("log-path").map(PathBuf::from);

tests/integration_tests/functional/test_cmd_line_parameters.py

@@ -3,6 +3,7 @@
 """Tests that ensure the correctness of the command line parameters."""
 
 import platform
+import subprocess
 from pathlib import Path
 
 import pytest
@@ -130,3 +131,18 @@ def test_cli_metrics_if_resume_no_metrics(uvm_plain, microvm_factory):
     # Then: the old metrics configuration does not exist
     metrics2 = Path(uvm2.jailer.chroot_path()) / metrics_path.name
     assert not metrics2.exists()
+
+
+def test_cli_no_params():
+    """
+    Test running firecracker with no parameters should work
+    """
+
+    fc_binary, _ = get_firecracker_binaries()
+    process = subprocess.Popen(fc_binary)
+    try:
+        process.communicate(timeout=3)
+        assert process.returncode is None
+    except subprocess.TimeoutExpired:
+        # The good case
+        process.kill()