Missing DB File by using Docker From Ubuntu:20.04

[dzygann]

Hi,

I don't see the mosquitto.db when I build a ubuntu dockerfile with a running mosquitto instance in it.
I would expect to see it in the /var/log/mosquitto, but it isn't there. Do I have to activate it firstly?
Here's my dockerfile:

From ubuntu:20.04
  
RUN apt-get update -y && apt-get install -y \
        openssl \
        mosquitto \
        apt-utils


EXPOSE 1883

RUN echo "\npersistence_file mosquitto.db" >> /etc/mosquitto/mosquitto.conf
RUN echo "\nlog_type all" >> /etc/mosquitto/mosquitto.conf

ENTRYPOINT ["mosquitto"]

CMD ["-c", "/etc/mosquitto/mosquitto.conf"]

This is the log from the docker:

root@d83f5d541aae:/# tail -f /var/log/mosquitto/mosquitto.log 
1639319954: mosquitto version 1.6.9 starting
1639319954: Config loaded from /etc/mosquitto/mosquitto.conf.
1639319954: Opening ipv4 listen socket on port 1883.
1639319954: Opening ipv6 listen socket on port 1883.
1639319954: New connection from 172.17.0.1 on port 1883.
1639319954: New client connected from 172.17.0.1 as auto-8CB8460A-A37F-95B8-6E2E-20AEF7B77EF6 (p2, c1, k60).
1639319954: No will message specified.
1639319954: Sending CONNACK to auto-8CB8460A-A37F-95B8-6E2E-20AEF7B77EF6 (0, 0)
1639319954: Received SUBSCRIBE from auto-8CB8460A-A37F-95B8-6E2E-20AEF7B77EF6
1639319954:     /home/sensors/temp/# (QoS 0)
1639319954: auto-8CB8460A-A37F-95B8-6E2E-20AEF7B77EF6 0 /home/sensors/temp/#
1639319954: Sending SUBACK to auto-8CB8460A-A37F-95B8-6E2E-20AEF7B77EF6
1639319978: New connection from 172.17.0.1 on port 1883.
1639319978: New client connected from 172.17.0.1 as auto-61D83116-7A64-5E1A-3F73-F7B745C31596 (p2, c1, k60).
1639319978: No will message specified.
1639319978: Sending CONNACK to auto-61D83116-7A64-5E1A-3F73-F7B745C31596 (0, 0)
1639319978: Received PUBLISH from auto-61D83116-7A64-5E1A-3F73-F7B745C31596 (d0, q0, r0, m0, '/home/sensors/temp/kitchen', ... (26 bytes))
1639319978: Sending PUBLISH to auto-8CB8460A-A37F-95B8-6E2E-20AEF7B77EF6 (d0, q0, r0, m0, '/home/sensors/temp/kitchen', ... (26 bytes))
1639319978: Received DISCONNECT from auto-61D83116-7A64-5E1A-3F73-F7B745C31596
1639319978: Client auto-61D83116-7A64-5E1A-3F73-F7B745C31596 disconnected.
1639319980: New connection from 172.17.0.1 on port 1883.
1639319980: New client connected from 172.17.0.1 as auto-C401567A-1516-8A54-5822-E7C9B42D1C01 (p2, c1, k60).
1639319980: No will message specified.

If I run mosquitto locally I can see the following entry in the log file:

1639217975: mosquitto version 2.0.14 running
1639219775: Saving in-memory database to /var/lib/mosquitto//mosquitto.db.
1639221576: Saving in-memory database to /var/lib/mosquitto//mosquitto.db.
1639223377: Saving in-memory database to /var/lib/mosquitto//mosquitto.db.

Do I have to configure something else to trigger the DB?

Thanks in advance.