System has not been booted with systemd as init system (PID 1). Can't operate - Docker Error

If you are starting a service in a docker container using systemctl command or you are configuring any service and you are getting above error, then you should check the output of the command 

ps aux

in your docker container. If PID 1 process is not systemd then this is the issue.

In above image, PID  1 process is bash because I launched the container using bash command.

While launching your container, you might have started the container with command bash or some other command. You should have launched the container with systemd command.

If you launch a container using systemd and your container is stopped after sometimes and you are not able to run it again, it means the image from which you are launching a container is not created for PID 1 systemd container.

You need an image which is created to handle such issue.

Solution :

Pull following image from docker repository.

docker run -d --name linuxamination --privileged -v /sys/fs/cgroup:/sys/fs/cgroup:ro jrei/systemd-ubuntu:20.04

I needed ubuntu 20.04 for my service, if you need Ubuntu 18.04 or Ubuntu 16.04, you can simply replace 20.04 with 18.04 or 16.04 in above command and it will pull the requested image.

Once you run above command, you do not need to launch container from this image as it is already launched and running. You need to log into the container using following command.

docker exec -it linuxamination bash

Once you are inside the container, your PID 1 prcess will be systemd

Now if you run the systemctl command or configure any service you will not get the same error again which you were getting before.

Systemd Error solution for different Docker Images :

𝐚) 𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝗳𝗼𝗿 𝗨𝗯𝘂𝗻𝘁𝘂
𝐏𝐮𝐥𝐥 𝐈𝐦𝐚𝐠𝐞 𝐜𝐨𝐦𝐦𝐚𝐧𝐝 :
docker run -d --name Linuxamination --privileged -v /sys/fs/cgroup:/sys/fs/cgroup:ro jrei/systemd-ubuntu:20.04
𝐋𝐨𝐠 𝐢𝐧𝐭𝐨 𝐭𝐡𝐞 𝐂𝐨𝐧𝐭𝐚𝐢𝐧𝐞𝐫 :
docker exec -it Linuxamination bash

𝐛) 𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝗳𝗼𝗿 𝗖𝗲𝗻𝘁𝗢𝗦
𝐏𝐮𝐥𝐥 𝐈𝐦𝐚𝐠𝐞 𝐜𝐨𝐦𝐦𝐚𝐧𝐝 :
docker run -d --name linuxaminationC8 --privileged -v /sys/fs/cgroup:/sys/fs/cgroup:ro alekseychudov/centos8-systemd
𝐋𝐨𝐠 𝐢𝐧𝐭𝐨 𝐭𝐡𝐞 𝐂𝐨𝐧𝐭𝐚𝐢𝐧𝐞𝐫 :
docker exec -it linuxaminationC8 bash

𝐜) 𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝗳𝗼𝗿 𝐃𝐞𝐛𝐢𝐚𝐧
𝐏𝐮𝐥𝐥 𝐈𝐦𝐚𝐠𝐞 𝐜𝐨𝐦𝐦𝐚𝐧𝐝 :
sudo docker run -d --name systemd-debian --privileged -v /sys/fs/cgroup:/sys/fs/cgroup:ro jrei/systemd-debian:11
𝐋𝐨𝐠 𝐢𝐧𝐭𝐨 𝐭𝐡𝐞 𝐂𝐨𝐧𝐭𝐚𝐢𝐧𝐞𝐫 :
sudo docker exec -it systemd-debian bash

𝐝) 𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝗳𝗼𝗿 𝗳𝗲𝗱𝗼𝗿𝗮
𝐏𝐮𝐥𝐥 𝐈𝐦𝐚𝐠𝐞 𝐜𝐨𝐦𝐦𝐚𝐧𝐝 :
sudo docker run -d --name systemd-fedora --privileged -v /sys/fs/cgroup:/sys/fs/cgroup:ro jrei/systemd-fedora
𝐋𝐨𝐠 𝐢𝐧𝐭𝐨 𝐭𝐡𝐞 𝐂𝐨𝐧𝐭𝐚𝐢𝐧𝐞𝐫 :
sudo docker exec -it systemd-fedora bash

𝗲) 𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝗳𝗼𝗿 𝗥𝗲𝗱𝗵𝗮𝘁 𝗟𝗶𝗻𝘂𝘅
𝐏𝐮𝐥𝐥 𝐈𝐦𝐚𝐠𝐞 𝐜𝐨𝐦𝐦𝐚𝐧𝐝 :
sudo docker run -d --name linuxamination --privileged -v /sys/fs/cgroup:/sys/fs/cgroup:ro registry.access.redhat.com/ubi8/ubi-init:8.1
𝐋𝐨𝐠 𝐢𝐧𝐭𝐨 𝐭𝐡𝐞 𝐂𝐨𝐧𝐭𝐚𝐢𝐧𝐞𝐫 :
sudo docker exec -it linuxamination bash

𝐟) 𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝗳𝗼𝗿 𝐀𝐥𝐦𝐚𝐋𝐢𝐧𝐮𝐱
𝐏𝐮𝐥𝐥 𝐈𝐦𝐚𝐠𝐞 𝐜𝐨𝐦𝐦𝐚𝐧𝐝 :
sudo docker run -d --name almalinuxamination --privileged -v /sys/fs/cgroup:/sys/fs/cgroup:ro almalinux/8-init
𝐋𝐨𝐠 𝐢𝐧𝐭𝐨 𝐭𝐡𝐞 𝐂𝐨𝐧𝐭𝐚𝐢𝐧𝐞𝐫 :
sudo docker exec -it almalinuxamination bash

You can see the solution in the following video.