RAG could't start with the enabled readOnlyRootFilesystem: true

[Shearwater1978]

Name and Version

ai-dial-rag 0.42.0

What steps will reproduce the bug?

1. Add this section in your values.yaml
   containerSecurityContext: readOnlyRootFilesystem: true
2. Apply this changes

What is the expected behavior?

I expect the application to start and, during operation, to not use a read-only file system but instead utilize the /tmp directory, which is writable.

What do you see instead?

1. I see that the application cannot start in Kubernetes.
   NAME READY STATUS RESTARTS AGE
   dial-rag-6b588cb8c4-lhbns 0/1 Error 1 (11s ago) 16s
2. In the Pod I see this errors:
   2026-07-09 05:14:15,347 INFO [aidial_rag.log_config] [log_config.py:41] [trace_id=0 span_id=0 resource.service.name=dial-rag trace_sampled=False] - Log config: {"log_level":"INFO","log_level_override":{}} Traceback (most recent call last): File "/opt/venv/bin/uvicorn", line 8, in <module> sys.exit(main()) ^^^^^^ File "/opt/venv/lib/python3.11/site-packages/click/core.py", line 1157, in __call__ return self.main(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/click/core.py", line 1078, in main rv = self.invoke(ctx) ^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/click/core.py", line 1434, in invoke return ctx.invoke(self.callback, **ctx.params) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/click/core.py", line 783, in invoke return __callback(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/uvicorn/main.py", line 410, in main run( File "/opt/venv/lib/python3.11/site-packages/uvicorn/main.py", line 578, in run server.run() File "/opt/venv/lib/python3.11/site-packages/uvicorn/server.py", line 61, in run return asyncio.run(self.serve(sockets=sockets)) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/uv/python/cpython-3.11.15-linux-x86_64-gnu/lib/python3.11/asyncio/runners.py", line 190, in run return runner.run(main) ^^^^^^^^^^^^^^^^ File "/opt/uv/python/cpython-3.11.15-linux-x86_64-gnu/lib/python3.11/asyncio/runners.py", line 118, in run return self._loop.run_until_complete(task) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/uv/python/cpython-3.11.15-linux-x86_64-gnu/lib/python3.11/asyncio/base_events.py", line 654, in run_until_complete return future.result() ^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/uvicorn/server.py", line 68, in serve config.load() File "/opt/venv/lib/python3.11/site-packages/uvicorn/config.py", line 473, in load self.loaded_app = import_from_string(self.app) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/uvicorn/importer.py", line 21, in import_from_string module = importlib.import_module(module_str) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/uv/python/cpython-3.11.15-linux-x86_64-gnu/lib/python3.11/importlib/__init__.py", line 126, in import_module return _bootstrap._gcd_import(name[level:], package, level) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "<frozen importlib._bootstrap>", line 1204, in _gcd_import File "<frozen importlib._bootstrap>", line 1176, in _find_and_load File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 690, in _load_unlocked File "<frozen importlib._bootstrap_external>", line 940, in exec_module File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed File "/aidial_rag/main.py", line 12, in <module> from aidial_rag.app import create_app File "/aidial_rag/app.py", line 14, in <module> from langchain.schema import BaseRetriever, Document File "/opt/venv/lib/python3.11/site-packages/langchain/schema/__init__.py", line 22, in <module> from langchain_core.output_parsers import ( File "<frozen importlib._bootstrap>", line 1229, in _handle_fromlist File "/opt/venv/lib/python3.11/site-packages/langchain_core/output_parsers/__init__.py", line 92, in __getattr__ result = import_attr(attr_name, module_name, __spec__.parent) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/langchain_core/_import_utils.py", line 36, in import_attr module = import_module(f".{module_name}", package=package) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/uv/python/cpython-3.11.15-linux-x86_64-gnu/lib/python3.11/importlib/__init__.py", line 126, in import_module return _bootstrap._gcd_import(name[level:], package, level) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/langchain_core/output_parsers/base.py", line 18, in <module> from langchain_core.language_models import LanguageModelOutput File "<frozen importlib._bootstrap>", line 1229, in _handle_fromlist File "/opt/venv/lib/python3.11/site-packages/langchain_core/language_models/__init__.py", line 112, in __getattr__ result = import_attr(attr_name, module_name, __spec__.parent) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/langchain_core/_import_utils.py", line 36, in import_attr module = import_module(f".{module_name}", package=package) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/uv/python/cpython-3.11.15-linux-x86_64-gnu/lib/python3.11/importlib/__init__.py", line 126, in import_module return _bootstrap._gcd_import(name[level:], package, level) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/langchain_core/language_models/base.py", line 44, in <module> from transformers import GPT2TokenizerFast # type: ignore[import-not-found] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/transformers/__init__.py", line 27, in <module> from . import dependency_versions_check File "/opt/venv/lib/python3.11/site-packages/transformers/dependency_versions_check.py", line 16, in <module> from .utils.versions import require_version, require_version_core File "/opt/venv/lib/python3.11/site-packages/transformers/utils/__init__.py", line 24, in <module> from .args_doc import ( File "/opt/venv/lib/python3.11/site-packages/transformers/utils/args_doc.py", line 30, in <module> from .generic import ModelOutput File "/opt/venv/lib/python3.11/site-packages/transformers/utils/generic.py", line 46, in <module> import torch # noqa: F401 ^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/torch/__init__.py", line 2161, in <module> from torch import _VF as _VF, functional as functional # usort: skip ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/torch/functional.py", line 8, in <module> import torch.nn.functional as F File "/opt/venv/lib/python3.11/site-packages/torch/nn/__init__.py", line 8, in <module> from torch.nn.modules import * # usort: skip # noqa: F403 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/torch/nn/modules/__init__.py", line 1, in <module> from .module import Module # usort: skip ^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/torch/nn/modules/module.py", line 17, in <module> from torch.utils._python_dispatch import is_traceable_wrapper_subclass File "/opt/venv/lib/python3.11/site-packages/torch/utils/__init__.py", line 8, in <module> from torch.utils import ( File "/opt/venv/lib/python3.11/site-packages/torch/utils/data/__init__.py", line 1, in <module> from torch.utils.data.dataloader import ( File "/opt/venv/lib/python3.11/site-packages/torch/utils/data/dataloader.py", line 24, in <module> import torch.utils.data.graph_settings File "/opt/venv/lib/python3.11/site-packages/torch/utils/data/graph_settings.py", line 8, in <module> from torch.utils.data.datapipes.iter.sharding import ( File "/opt/venv/lib/python3.11/site-packages/torch/utils/data/datapipes/__init__.py", line 1, in <module> from torch.utils.data.datapipes import dataframe as dataframe, iter as iter, map as map File "/opt/venv/lib/python3.11/site-packages/torch/utils/data/datapipes/dataframe/__init__.py", line 1, in <module> from torch.utils.data.datapipes.dataframe.dataframes import ( File "/opt/venv/lib/python3.11/site-packages/torch/utils/data/datapipes/dataframe/dataframes.py", line 4, in <module> from torch.utils.data.datapipes._decorator import functional_datapipe File "/opt/venv/lib/python3.11/site-packages/torch/utils/data/datapipes/_decorator.py", line 7, in <module> from torch.utils.data.datapipes.datapipe import IterDataPipe, MapDataPipe File "/opt/venv/lib/python3.11/site-packages/torch/utils/data/datapipes/datapipe.py", line 17, in <module> dill = import_dill() ^^^^^^^^^^^^^ File "/opt/venv/lib/python3.11/site-packages/torch/utils/_import_utils.py", line 31, in import_dill import dill File "/opt/venv/lib/python3.11/site-packages/dill/__init__.py", line 33, in <module> from .session import ( File "/opt/venv/lib/python3.11/site-packages/dill/session.py", line 36, in <module> TEMPDIR = pathlib.PurePath(tempfile.gettempdir()) ^^^^^^^^^^^^^^^^^^^^^ File "/opt/uv/python/cpython-3.11.15-linux-x86_64-gnu/lib/python3.11/tempfile.py", line 316, in gettempdir return _os.fsdecode(_gettempdir()) ^^^^^^^^^^^^^ File "/opt/uv/python/cpython-3.11.15-linux-x86_64-gnu/lib/python3.11/tempfile.py", line 309, in _gettempdir tempdir = _get_default_tempdir() ^^^^^^^^^^^^^^^^^^^^^^ File "/opt/uv/python/cpython-3.11.15-linux-x86_64-gnu/lib/python3.11/tempfile.py", line 224, in _get_default_tempdir raise FileNotFoundError(_errno.ENOENT, FileNotFoundError: [Errno 2] No usable temporary directory found in ['/tmp', '/var/tmp', '/usr/tmp', '/']

Additional information

No response