Can't launch demon for installation by DEB package when using Debian Docker image (Bullseye)

[junghanKang]

Describe the bug

I used to use php:7.1.12-apache-jessie docker image and installed fluentd with
# td-agent 3 curl -L https://toolbelt.treasuredata.com/sh/install-debian-jessie-td-agent3.sh | sh
and was able to use /etc/init.d/td-agent script.

However, when I upgrade the image to php:7.3-apache which is Debian Bullseye,
# td-agent 4 curl -L https://toolbelt.treasuredata.com/sh/install-debian-buster-td-agent4.sh | sh
can't generate /etc/init.d/td-agent script.

When I did several trials, I found just running td-agent which seems running /usr/sbin/td-agent starts fluentd without issues.

Could you check this difference for Deamon launch?
Thank you.

Link to the problematic documentation

https://docs.fluentd.org/installation/install-by-deb#init-d

Expected explanation

I'd like to get confirmation my alternative way to initiate fluentd on docker container is appropriate.

Additional context

No response

[repeatedly]

Newer debian uses systemd and td-agent 4 also uses it on systemd based distribution.

https://docs.fluentd.org/installation/install-by-deb#systemd

[junghanKang]

Newer debian uses systemd and td-agent 4 also uses it on systemd based distribution.

https://docs.fluentd.org/installation/install-by-deb#systemd

Ok, that's why init.d doesn't work with new debian.
But unfortunately, it seems hard to use systemd in docker container.

root@b168b0d775be:# systemctl status td-agent.service
System has not been booted with systemd as init system (PID 1). Can't operate.
Failed to connect to bus: Host is down
root@b168b0d775be:# sudo systemctl status td-agent.service
System has not been booted with systemd as init system (PID 1). Can't operate.
Failed to connect to bus: Host is down 

then, for now, I guess I need to use /usr/sbin/td-agent

Thank you for the reply.