Use a sidekick service

Its possible to use https://github.com/bsphere/lecat packed into a Docker image — https://registry.hub.docker.com/u/gbenhaim/lecat/

Then write a sidekick service,
for example:

https://registry.hub.docker.com/u/gbenhaim/lecat/

~ $ cat services/backend-log.service 
[Unit]
Description=Backend log 
BindsTo=backend.service
After=backend.service

[Service]
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker kill backend-log
ExecStartPre=-/usr/bin/docker rm backend-log
ExecStartPre=/usr/bin/bash -c “/usr/bin/docker pull gbenhaim/lecat”
ExecStart=/usr/bin/bash -c “/usr/bin/journalctl -f -u backend | /usr/bin/docker run —name backend-log -i gbenhaim/lecat -token=`etcdctl get /settings/backend/le_token`”
ExecStop=/usr/bin/docker stop backend-log

[X-Fleet]
MachineOf=backend.service