Fix recordings bind-mount write permissions in Docker Compose #23

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opened 2026-04-29 20:23:50 +02:00 by wandabastyle · 0 comments

wandabastyle commented

2026-04-29 20:23:50 +02:00

(Migrated from github.com)

Problem

The container is configured to run as a non-root user:

user: "1000:1000"

but the recordings bind mount may not be writable by that UID/GID on the host:

volumes:
  - ./recordings:/app/recordings

This can cause write failures when the app tries to create or save files under /app/recordings.

chmod 775 alone is not enough unless the folder owner or group matches the container process UID/GID.

How to verify

On the host:

ls -ldn ./recordings

Expected owner/group should usually be:

1000 1000

Inside the container:

docker compose exec twitch-relay sh -lc 'id; ls -ldn /app/recordings; touch /app/recordings/test'

If touch fails, the bind mount permissions are wrong.

Proposed fix

Ensure the host folder exists and is owned by UID/GID 1000:1000 before starting the container:

mkdir -p ./recordings
sudo chown -R 1000:1000 ./recordings
chmod -R u+rwX,g+rwX ./recordings

Optionally make the bind mount mode explicit for readability:

volumes:
  - ./recordings:/app/recordings:rw

Note: :rw is Docker’s default, so this is not the main fix. The important part is matching the host folder ownership/permissions to the configured container user.

## Problem The container is configured to run as a non-root user: ```yaml user: "1000:1000" ``` but the `recordings` bind mount may not be writable by that UID/GID on the host: ```yaml volumes: - ./recordings:/app/recordings ``` This can cause write failures when the app tries to create or save files under `/app/recordings`. `chmod 775` alone is not enough unless the folder owner or group matches the container process UID/GID. ## How to verify On the host: ```bash ls -ldn ./recordings ``` Expected owner/group should usually be: ```text 1000 1000 ``` Inside the container: ```bash docker compose exec twitch-relay sh -lc 'id; ls -ldn /app/recordings; touch /app/recordings/test' ``` If `touch` fails, the bind mount permissions are wrong. ## Proposed fix Ensure the host folder exists and is owned by UID/GID `1000:1000` before starting the container: ```bash mkdir -p ./recordings sudo chown -R 1000:1000 ./recordings chmod -R u+rwX,g+rwX ./recordings ``` Optionally make the bind mount mode explicit for readability: ```yaml volumes: - ./recordings:/app/recordings:rw ``` Note: `:rw` is Docker’s default, so this is not the main fix. The important part is matching the host folder ownership/permissions to the configured container user.