`Bug`: Guest relocation fails in PSI mode due to KeyError on non-existent metric key

When running ProxLB in PSI mode, the guest relocation fails with a KeyError. The problem occurs because the code dynamically constructs a key using the method and mode values (n[f"{method}_{mode}_percent"]). In PSI mode, this results in a non-existent key (memory_psi_percent) in the nodes’ data structure, causing the crash. This prevents ProxLB from completing the load balancing and guest relocation process. Weighting Score: 8 This issue is high priority because it causes the load balancing process to fail entirely in PSI mode, which may affect production systems. Log ``` Traceback (most recent call last): File "/Users/bosettie/Applications/PyCharm.app/Contents/plugins/python-ce/helpers/pydev/pydevd.py", line 1570, in _exec pydev_imports.execfile(file, globals, locals) # execute the script ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/bosettie/Applications/PyCharm.app/Contents/plugins/python-ce/helpers/pydev/_pydev_imps/_pydev_execfile.py", line 18, in execfile exec(compile(contents+"\n", file, 'exec'), glob, loc) ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/bosettie/ProxLB/proxlb/main.py", line 118, in <module> main() ~~~~^^ File "/Users/bosettie/ProxLB/proxlb/main.py", line 100, in main Calculations.relocate_guests(proxlb_data) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^ File "/Users/bosettie/ProxLB/proxlb/models/calculations.py", line 425, in relocate_guests highest_node = max(proxlb_data["nodes"].values(), key=lambda n: n[f"{method}_{mode}_percent"]) File "/Users/bosettie/ProxLB/proxlb/models/calculations.py", line 425, in <lambda> highest_node = max(proxlb_data["nodes"].values(), key=lambda n: n[f"{method}_{mode}_percent"]) ~^^^^^^^^^^^^^^^^^^^^^^^^^^^^ KeyError: 'memory_psi_percent' ``` https://github.com/gyptazy/ProxLB/blob/65b1bd5feef6b587119b284467e978cebe4351b5/proxlb/models/calculations.py#L425 Meta Version: v1.1.11 Running as: Container