Configuring Podman for Quarkus Dev Services and Testcontainers on Linux
Podman is a daemonless container engine for developing, managing, and running Containers on Linux systems. Since the release of version 3, Podman allows the user to run a service emulating a Docker API provided on a Unix socket. This makes it possible for Testcontainers and Quarkus Dev Services to be utilized with Podman.
Directions in this article will not work on macOS and Microsoft Windows.
Requirements
-
Running on a Linux system with Podman 3.x installed.
-
podman-dockerinstalled to emulate the Docker CLI for Quarkus Dev Services. -
(optional)
podman-remoteinstalled for verification steps.
Configuración
TL;DR
The following commands will set up Podman and environment variables up to work with Quarkus Dev Services and Testcontainers:
# Install the required podman packages from dnf. If you're not using rpm based
# distro, replace with respective package manager
sudo dnf install podman podman-docker
# Enable the podman socket with Docker REST API
systemctl --user enable podman.socket --now
# Set the required envvars
export DOCKER_HOST=unix:///run/user/${UID}/podman/podman.sock
export TESTCONTAINERS_RYUK_DISABLED=trueWhat this configuration does is explained below, along with basic troubleshooting.
Configuring the Podman service
Podman is a daemonless container engine. Quarkus Dev Services and Testcontainers expect a running Docker daemon listening at a Unix socket. Since version 3, Podman can be configured to create a service listening at a Unix socket and this service can be used with Dev Services and Testcontainers.
By convention, the Docker clients attempt to connect to the service specified by URL configured in the DOCKER_HOST
environment variable, so this variable needs to be configured to point to the Unix socket that the Podman service will
be listening on:
export DOCKER_HOST=unix:///run/user/${UID}/podman/podman.sock|
This setting will only apply to the current terminal session. To make this configuration persistent, add the line to
the profile files of your shell (e.g. |
Testcontainers and Quarkus Dev Services also expect the container service they make requests against to be non-interactive. In case you have multiple registries configured in your Docker or Podman configuration, Podman responds with a prompt asking which registry should be used to pull containers from in case the containers pulled are specified by short name.
You can disable this prompt by setting the short-name-mode="disabled" configuration property of Podman in
/etc/containers/registries.conf.
|
This setting is security sensitive. Please see Container image short names in Podman before changing this setting. |
Finally, let’s start the Podman service listening on the socket previously specified by the DOCKER_HOST environment
variable.
Podman is distributed with user-local systemd units on apt and dnf package managers configured to run a rootless
Podman service. This means that the Podman process will be launched only with the privileges of the user you are logged
in as, that the containers and configuration are stored in your home directory and that this service listens at
unix:///run/user/${UID}/podman/podman.sock. In most of the Linux distributions, you can enable this service with the
following command:
systemctl --user enable podman.socket --nowYou can verify that the container service is really running and responding at the URI specified by DOCKER_HOST with
podman-remote.
podman-remote infoPodman’s support for Ryuk container is currently flaky. Ryuk is a container that Testcontainers uses to clean up any containers spawned by Testcontainers after the end of their usage in Java code. You can configure Testcontainers not to use Ryuk.
export TESTCONTAINERS_RYUK_DISABLED=true|
This setting will only apply to the current terminal session. To make this configuration persistent, add the line to
the profile files of your shell (e.g. |
Podman is now available to respond to the Java Docker client used in Testcontainers. Please note that the Quarkus Dev
Services require that a docker command is available on PATH. The podman-docker package on Linux distributions
provides a Docker CLI emulation layer for Podman.
The future releases of Quarkus will remove the expectation for docker command available on PATH.
Migrating from Docker
If you have previously been running Docker on a version that did not support cgroups V2 on modern Linux distributions, a workaround setting the cgroups to V1 had to be enabled. This applied for Docker versions older than 19, included.
You can check whether the workaround has been previously applied to your system with the following command:
sudo grubby --info=ALL | grep "systemd.unified_cgroup_hierarchy=0"If the output is present, this means that kernel argument to set cgroups to V1 has been applied. You can remove the kernel argument with the following command, re-enabling cgroups V2:
sudo grubby --update-kernel=ALL --remove-args="systemd.unified_cgroup_hierarchy=0"This setting will only take effect after a reboot.
