Redis – DockerOperator failure: Permission denied for docker.sock

I run Airflow using Docker-compose and I wanted to create a DAG with a DockerOperator in order to run a docker container.

The thing is I keep on getting the same error when looking at the logs for the DAG in Airflow:

[2021-05-12 11:37:38,060] {taskinstance.py:1482} ERROR - Task failed with exception
Traceback (most recent call last):
  File "/home/airflow/.local/lib/python3.6/site-packages/urllib3/connectionpool.py", line 677, in urlopen
    chunked=chunked,
  File "/home/airflow/.local/lib/python3.6/site-packages/urllib3/connectionpool.py", line 392, in _make_request
    conn.request(method, url, **httplib_request_kw)
  File "/usr/local/lib/python3.6/http/client.py", line 1287, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/local/lib/python3.6/http/client.py", line 1333, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/usr/local/lib/python3.6/http/client.py", line 1282, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/usr/local/lib/python3.6/http/client.py", line 1042, in _send_output
    self.send(msg)
  File "/usr/local/lib/python3.6/http/client.py", line 980, in send
    self.connect()
  File "/home/airflow/.local/lib/python3.6/site-packages/docker/transport/unixconn.py", line 43, in connect
    sock.connect(self.unix_socket)
PermissionError: [Errno 13] Permission denied

The file at issue is docker.stock which has the following rights:

srw-rw----. 1 root docker

Note that in the Docker-compose yml file I specified the user to be the default one and the group to be root, plus I mounted the docker.sock directory as follows:

- /var/run/docker.sock:/var/run/docker.sock:z

And here is the docker-compose:

version: '3'
x-airflow-common:
  &airflow-common
  image: ${AIRFLOW_IMAGE_NAME:-apache/airflow:2.0.2}
  environment:
    &airflow-common-env
    AIRFLOW_UID: 8854
    AIRFLOW_GID: 0
    AIRFLOW__CORE__EXECUTOR: CeleryExecutor
    AIRFLOW__CORE__SQL_ALCHEMY_CONN: postgresql+psycopg2://airflow:airflow@postgres/airflow
    AIRFLOW__CELERY__RESULT_BACKEND: db+postgresql://airflow:airflow@postgres/airflow
    AIRFLOW__CELERY__BROKER_URL: redis://:@redis:6379/0
    AIRFLOW__CORE__FERNET_KEY: ''
    AIRFLOW__CORE__DAGS_ARE_PAUSED_AT_CREATION: 'true'
    AIRFLOW__CORE__LOAD_EXAMPLES: 'false'
    AIRFLOW__CORE__DAGS_FOLDER: '/data/python/airflow/dags'
    AIRFLOW__API__AUTH_BACKEND: 'airflow.api.auth.backend.basic_auth'
  volumes:
    - /data/graylog/python/airflow/dags:/data/python/airflow/dags:z
    - /data/graylog/python/airflow/logs:/data/python/airflow/logs:z
    - /data/graylog/python/airflow/plugins:/data/python/airflow/plugins:z
    - /data/graylog/python/timestamp:/data/python/timestamp:z
    - /data/graylog/python/python_scripts:/data/python/python_scripts:z
    - /var/run/docker.sock:/var/run/docker.sock:z
  user: "${AIRFLOW_UID:-8854}:${AIRFLOW_GID:-0}"
  depends_on:
    redis:
      condition: service_healthy
    postgres:
      condition: service_healthy

services:
  postgres:
    image: postgres:13
    environment:
      POSTGRES_USER: airflow
      POSTGRES_PASSWORD: airflow
      POSTGRES_DB: airflow
    volumes:
      - postgres-db-volume:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD", "pg_isready", "-U", "airflow"]
      interval: 5s
      retries: 5
    restart: always

  redis:
    image: redis:latest
    ports:
      - 6379
    healthcheck:
      test: ["CMD", "redis-cli", "ping"]
      interval: 5s
      timeout: 30s
      retries: 50
    restart: always

  airflow-webserver:
    <<: *airflow-common
    command: webserver
    ports:
      - 8080:8080
    healthcheck:
      test: ["CMD", "curl", "--fail", "http://localhost:8080/health"]
      interval: 10s
      timeout: 10s
      retries: 5
    restart: always

  airflow-scheduler:
    <<: *airflow-common
    command: scheduler
    restart: always

  airflow-worker:
    <<: *airflow-common
    command: celery worker
    restart: always

  airflow-init:
    <<: *airflow-common
    command: version
    environment:
      <<: *airflow-common-env
      _AIRFLOW_DB_UPGRADE: 'true'
      _AIRFLOW_WWW_USER_CREATE: 'true'
      _AIRFLOW_WWW_USER_USERNAME: ${_AIRFLOW_WWW_USER_USERNAME:-airflow}
      _AIRFLOW_WWW_USER_PASSWORD: ${_AIRFLOW_WWW_USER_PASSWORD:-airflow}

  flower:
    <<: *airflow-common
    command: celery flower
    ports:
      - 5555:5555
    healthcheck:
      test: ["CMD", "curl", "--fail", "http://localhost:5555/"]
      interval: 10s
      timeout: 10s
      retries: 5
    restart: always

volumes:
  postgres-db-volume:

Can someone help me with this please? Thanks