fixup: detect ssh availability when joining

crmsh/bootstrap.py

@@ -1789,7 +1789,14 @@ def join_ssh_with_ssh_agent(
 ):
     # As ssh-agent is used, the local_user does not have any effects
     shell = sh.SSHShell(local_shell, 'root')
-    # FIXME: detect the availability of ssh session
+    if not shell.can_run_as(seed_host, seed_user):
+        raise ValueError(f'Failed to login to {seed_user}@{seed_host}')
+    if seed_user != 'root' and 0 != shell.subprocess_run_without_input(
+            seed_host, seed_user, 'sudo true',
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+    ).returncode:
+        raise ValueError(f'Failed to sudo on {seed_user}@{seed_host}')
     authorized_key_manager = ssh_key.AuthorizedKeyManager(shell)
     for key in ssh_public_keys:
         authorized_key_manager.add(None, local_user, key)