Error: dynamodb docker unable to open database file

Unable to open database file from DynamoDB Local in Docker usually means its SQLite database path is missing or not writable by the container process. A read-only mount, incorrect working directory or full disk can produce the same symptom.

1. Inspect container logs and the command, especially -dbPath and the working directory. Relative paths are resolved inside the container.
2. Confirm the directory exists in the container and the host volume is mounted there with write access.
3. Check the UID/GID of the running process and grant that identity access to the data directory and existing files. SQLite needs directory access for its auxiliary files too.
4. Check free disk space, mount restrictions and host security controls if the path and ownership are correct.

docker logs dynamodb-local
docker inspect dynamodb-local --format '{{json .Mounts}}'
docker exec dynamodb-local sh -c 'id; pwd; ls -ld /home/dynamodblocal/data'

Replace the example data path with your -dbPath. Avoid chmod 777: it grants every local user write access and can hide a mistaken mount. As a diagnostic, start a separate disposable -inMemory instance on another port to distinguish filesystem problems from server startup problems. It will not preserve data after shutdown.

See Docker setup and AWS documentation.