Selenium Container Fails with Read-Only Root Filesystems on AWS ECS

[AVandana-1806]

We are using the Selenium Hub (4.28.1) Docker container to run the browser tests in an AWS ECS environments. As per our security hardening measures, We aim to run the container with read-only root filesystems. However, when we enable this setting, the container fails to start.

Steps Taken:

• We deployed the Selenium Hub Container in AWS ECS with readOnlyRootFileSystem: true
• The container crashes immediately due to permission issues, likely because some processes attempt to write to the root filesystem.

Questions:

1. Is there any official guidance or workaround to make Selenium Hub work with read-only root filesystems?
2. Are there specific writable paths we can mount as volumes to bypass this issue?
3. Are there any future plans to make Selenium Hub fully compatible with read-only root filesystems?

[VietND96]

Hello, can you share the container logs, I want to see them before answering other queries.

[AVandana-1806]

---

timestamp	message
1740592203324	Traceback (most recent call last):
1740592203324	File "/usr/bin/supervisord", line 33, in
1740592203324	sys.exit(load_entry_point('supervisor==4.2.5', 'console_scripts', 'supervisord')())
1740592203324	^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1740592203324	File "/usr/lib/python3/dist-packages/supervisor/supervisord.py", line 351, in main
1740592203324	options = ServerOptions()
1740592203324	^^^^^^^^^^^^^^^
1740592203324	File "/usr/lib/python3/dist-packages/supervisor/options.py", line 441, in init
1740592203324	existing_directory, default=tempfile.gettempdir())
1740592203324	^^^^^^^^^^^^^^^^^^^^^
1740592203324	File "/usr/lib/python3.12/tempfile.py", line 454, in gettempdir
1740592203325	return _os.fsdecode(_gettempdir())
1740592203325	^^^^^^^^^^^^^
1740592203325	File "/usr/lib/python3.12/tempfile.py", line 447, in _gettempdir
1740592203325	tempdir = _get_default_tempdir()
1740592203325	^^^^^^^^^^^^^^^^^^^^^^
1740592203325	File "/usr/lib/python3.12/tempfile.py", line 362, in _get_default_tempdir
1740592203325	raise FileNotFoundError(_errno.ENOENT,
1740592203325	FileNotFoundError: [Errno 2] No usable temporary directory found in ['/tmp', '/var/tmp', '/usr/tmp', '/']

---

[AVandana-1806]

@VietND96 Do we have update on this?

[VietND96]

Hi, follow the error, it is due to supervisors (process manager in container) needs to write logs to a file under /tmp
Can we try to consider /tmp to be part of the root filesystem?

[AVandana-1806]

@VietND96 We could give a try.