linuxexpert-practice-labs/labs/lfcs/1-7-containers/README.md

LFCS 1.7: Containers

Running a container with a port and a read-only bind mount, a container as a service with Quadlet, a rootless container that starts at boot, building an image, and configuring Docker.

Before you start

The VM needs internet access to pull images. The lab installs Podman and creates user alice (password Lab-Pass-1). Docker isn't installed: that's part of task 5. Docker Hub limits anonymous pulls; if you hit the limit, mirror.gcr.io/library/nginx is the same image.

Tasks

1. As root, run nginx in a container named web on host port 8080, serving /srv/web read-only. curl localhost:8080 returns the index.html you put in /srv/web. On the RHEL-family VM, keep SELinux enforcing.
2. Make that container start at every boot with Quadlet, as web.service. Remove the container from the previous task first (podman rm -f web); Quadlet names its container systemd-web unless you set ContainerName=web. After a reboot, systemctl is-active web prints active and the page still loads.
3. As alice, run a rootless container that keeps its data in a named volume and starts at boot. After a reboot, without logging in as alice, sudo -u alice XDG_RUNTIME_DIR=/run/user/$(id -u alice) podman ps shows it running.
4. As root, build an image from a Containerfile that serves a static page, tag it site:1.0, and run it with -e setting a variable the page doesn't need. Keep the container.
5. Install Docker, set its log driver to journald, and restart it.

Hints

• podman run -d --name -p -v SRC:DST:ro,Z, podman port, podman inspect.
• A .container file in /etc/containers/systemd/, systemctl daemon-reload; the [Install] section makes it start at boot.
• ~/.config/containers/systemd/, systemctl --user from a real login (ssh), loginctl enable-linger, podman volume ls.
• podman build -t, podman images, podman run -e.
• docker.io on Ubuntu; Docker's own docker-ce repository on RHEL relatives. /etc/docker/daemon.json, docker info.