Issue creating a Packer debian image with systemd enabled - docker

Question

I am using WSL2 on Windows 10. I have the most v1.0.3 of WSL which allows systemd (systemctl) and am using Ubuntu 20.04 as my default distribution.
I have a functioning Dockerfile to build a Debian image with systemd enabled. It works perfectly fine. I found it at this link: https://github.com/robertdebock/docker-debian-systemd.
However I was tasked to redo this Dockerfile in Packer, since Packer is our standard for buildling images instead of Dockerfiles. I am having issues because even though I feel I've copied everything from the Dockerfile into my HCL2 code, when I launch the container in docker-compose it comes up saying that systemctl isn't available. systemd is definitely installed on the packer image.
Here is my HCL2 code:
packer {
required_plugins {
docker = {
version = ">= 0.0.7"
source = "github.com/hashicorp/docker"
}
}
}
source "docker" "debian" {
image = "debian:11"
commit = true
changes = [
"ENV container docker",
"ENV DEBIAN_FRONTEND noninteractive",
"VOLUME /sys/fs/cgroup"
]
}
build {
name = "${var.docker_login_server}/mycompany-debian-11-docker"
sources = [
"source.docker.debian"
]
provisioner "shell" {
environment_vars = []
inline = [
"apt-get update",
"apt-get install --no-install-recommends -y systemd systemd-sysv procps sudo ca-certificates unzip wget curl",
"apt-get clean",
"curl 'https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip' -o 'awscliv2.zip'",
"unzip awscliv2.zip",
"sudo ./aws/install",
"sudo adduser --disabled-password --gecos '' admin",
"rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*",
"rm -rf /lib/systemd/system/multi-user.target.wants/*",
"rm -rf /etc/systemd/system/*.wants/*",
"rm -rf /lib/systemd/system/local-fs.target.wants/*",
"rm -rf /lib/systemd/system/sockets.target.wants/*udev*",
"rm -rf /lib/systemd/system/sockets.target.wants/*initctl*",
"rm -rf /lib/systemd/system/sysinit.target.wants/systemd-tmpfiles-setup*",
"rm -rf /lib/systemd/system/systemd-update-utmp*"
]
}
post-processors {
post-processor "docker-tag" {
repository = "${var.docker_login_server}/mycompany-debian-11-docker"
tags = ["11"]
}
post-processor "docker-push" {
login = true
login_username = "${var.docker_login_username}"
login_password = "${var.docker_login_password}"
login_server = "${var.docker_login_server}"
keep_input_artifact = false
}
}
}
Note on the above, if I add this line to the source -> changes[] section, when I try to run the image it fails with a syntax error (below), so I removed it for now.
"CMD /lib/systemd/systemd"
Container error: /bin/sh: 1: Syntax error: "(" unexpected
Once the image is successfully build in packer and sent to our internal image repo, I use docker-compose to run it like this:
services:
debian:
container_name: debian
image: {internalRepoUrl}/mycompany-debian-11-docker:11
tty: true
volumes:
- /sys/fs/cgroup:/sys/fs/cgroup:ro
privileged: true
When I open a terminal on the container and try to run systemctl, I get this error:
System has not been booted with systemd as init system (PID 1). Can't operate.
Failed to connect to bus: Host is down
However, if I launch the image created with the Dockerfile, it works fine. It seems there is simply something I need to do in my Packer HCL that isn't obvious to me. Does anyone have any suggestions?
See the above problem description. I tried replicating what is working in a Dockerfile in Packer. I was expecting that the debian instance would come up with systemctl functioning, similar to the way it does when I create the image using the Dockerfile referenced in the link above.