Why are reboots comparatively slower when a docker container is running on Red Hat Enterprise Linux 7 ?

Issue

• Why are reboots comparatively slower when a docker container is running on Red Hat Enterprise Linux 7 ?. System reboots are slower by 1 minute or higher when compared to a system that does not have a running container.

Container is created using the command

docker create -ti --privileged --name redhat_test registry.access.redhat.com/rhel:latest /sbin/init

and started using systemd unit file with the following contents'/etc/systemd/system/redhat_container.service'

[Unit]
Description=redhat container
After=docker.service network.service
Requires=docker.service

[Service]
ExecStart=/usr/bin/docker start -a "redhat_test"
ExecStop=/usr/bin/docker stop -t 15 "redhat_test"
Restart=always
RestartSec=10s
TimeoutStartSec=0
TimeoutStopSec=130s

[Install]
WantedBy=multi-user.target