FreeIPA server container

This repository contains Dockerfiles and additional files for creating FreeIPA server container images from the official yum/dnf repositories of multiple Linux distributions.

The choice of the OS and version depends on the purpose of the FreeIPA setup, the same as it would when installing FreeIPA on a bare metal host or in a virtual machine. Newer versions are typically better and are also useful for testing interoperability with latest version of FreeIPA; for long term production setups, Fedora might be updating too quickly and sometimes be too new, compared to the other systems.

Available images

FreeIPA server container images are built from this repository automatically and pushed to

So the full canonical path for pulling images from container registry is one of

quay.io/freeipa/freeipa-server:<tag>
docker.io/freeipa/freeipa-server:<tag>

The tag matches the Dockerfile suffix, identifying the operating system the image is based on.

The images get rebuilt regularly, with latest version of both the FreeIPA and dependent packages in the given operating system version, both for security and bug fixes. If you require stricter control over pulling in new image builds into your deployments, tag them into your namespace or push to your registry and set up a testing/stage/production regression testing and process.

The container images registries also contain more specific tags that identify the version of FreeIPA in the given image. Note however that the underlying dependency packages could have been updated many times even if the FreeIPA packages stayed the same.

Building images locally

When building the FreeIPA server container images locally, for development or debugging, use the -f option to podman build or docker build to pick a Dockerfile for the specific operating system and version.

For example, to build image based on CentOS 9 Stream packages using podman, use

podman build -t localhost/freeipa-server -f Dockerfile.centos-9-stream .

and to create FreeIPA image based on Fedora rawhide with docker, call

docker build -t localhost/freeipa-server -f Dockerfile.fedora-rawhide .

Note that when using docker / moby-engine, the docker daemon needs to be running.

Running FreeIPA server container

While in an ideal case the use of FreeIPA server container can simplify the setup, prior experience with FreeIPA is definitely useful. Getting the container set up and running can be also more challenging than other typical containerized workloads.

Running the container

The FreeIPA container runs systemd to manage all the necessary services within a single container. Running a systemd-based container may require special handling or parameters to be passed to the container runtime. When you hit an issue, debug by simplifying the setup, retry with basic podman or docker instead of continuing with more complex orchestration like docker-compose or Kubernetes, try to get plain systemd running in container properly first (see Debugging section below).

Note that privileged setup is not supported and will not work — we want the FreeIPA server container to be reasonably isolated from the host and vice versa.

With podman, normal podman run is typically enough and works for rootless setups as well.

Use of rootless docker (check with docker info --format '{{ .ClientInfo.Context }}') is only supported on systems with cgroups v2 (determine by existence of /sys/fs/cgroup/cgroup.controllers). It may then be necessary to use docker run option

--cgroupns=host -v /sys/fs/cgroup:/sys/fs/cgroup:rw

With rootful docker daemon, user namespace remapping may be needed for the container cgroup to be properly created and mounted within the container read-write as systemd expects it, with

{ "userns-remap": "default" }

in /etc/docker/daemon.json. Restart of the docker service is needed after this configuration change. This approach also isolates the root in the container from the root on the host, which is a good thing in general. On the other hand, it is a global daemon configuration so it will affect other containers as well.

With docker on systems with cgroups v1, there is often a hybrid setup present with cgroups v2 available as /sys/fs/cgroup/unified, so invoking docker run with option

-v /sys/fs/cgroup/unified:/sys/fs/cgroup:rw

should work.

On SELinux enabled systems, it may be also necessary to enable running systemd in containers by setting SELinux boolean container_manage_cgroup on the host with

setsebool -P container_manage_cgroup 1

Server configuration and data

The FreeIPA container will store all its configurations, data, and logs on volume mounted to /data directory in the container. If we create directory which will hold the server data on the host with

mkdir ipa-data

we can then create the FreeIPA container with podman using

podman run --name freeipa-server-container -ti \
    -h ipa.example.test --read-only \
    -v $(pwd)/ipa-data:/data:Z <image> [ ... ]

and with docker using

docker run --name freeipa-server-container -ti \
    -h ipa.example.test --read-only \
    -v $(pwd)/ipa-data:/data:Z <image> [ ... ]

When running in rootless mode, make sure the volume directory on the host is owned by uid which becomes uid 0 in the container.

Of course, the volume can also be created in the container system, for example with

podman volume create freeipa-data
podman run --name freeipa-server-container -ti \
    -h ipa.example.test --read-only \
    -v freeipa-data:/data:Z <image> [ ... ]

Initial FreeIPA master setup

Upon the first invocation with empty directory mounted to /data, the container will run ipa-server-install (or ipa-replica-install) to configure FreeIPA master or replica. For example

podman run -ti -h ipa.example.test --read-only \
    -v /var/lib/ipa-data:/data:Z \
    <image> ipa-server-install -r EXAMPLE.TEST --no-ntp

will run interactive ipa-server-install and configure the FreeIPA master using the inputs provided. For unattended initial installation, use the -U argument to ipa-server-install and specify all the necessary inputs as argument on the command line, for example

docker run -h ipa.example.test --read-only \
    -v /var/lib/ipa-data:/data:Z \
    -e PASSWORD=Secret123 \
    <image> ipa-server-install -U -r EXAMPLE.TEST --no-ntp

The environment variable PASSWORD sets both the Directory Manager and admin passwords, an equivalent of specifying --admin-password and --ds-password on the command line.

The ipa-server-install command is the default and can be omitted.

Sometimes it is not convenient or possible to specify the arguments to ipa-server-install as arguments to podman run or docker run. In the case they can be specified either using environment variable IPA_SERVER_INSTALL_OPTS using the -e option, or they can be passed in using file ipa-server-install-options in the directory mounted to the container as /data. For example, when /var/lib/ipa-data/ipa-server-install-options contains

--realm=EXAMPLE.TEST
--ds-password=The-directory-server-password
--admin-password=The-admin-password

and podman run or docker run is executed with -v /var/lib/ipa-data:/data:Z, the content of ipa-server-install-options will be passed as arguments to ipa-server-install.

Since the ipa-server-install-options typically contains passwords, it is also possible to use podman secret create to store the whole content of that file, and the invoke podman run with options like

--secret source=options-with-credentials,target=/data/ipa-server-install-options

to expose the options in the container. The same holds for docker invocation.

If you want to instruct the container to create a replica, specify the ipa-replica-install command in the podman run or docker run parameters:

podman run -ti -h ipa.example.test --read-only \
   -v /var/lib/ipa-data:/data:Z \
   <image> ipa-replica-install [ opts ]

Using ipa-replica-install-options also works and will invoke ipa-replica-install and pass it its content as argument, the same way ipa-server-install-options works for ipa-server-install.

Routine invocation

Upon subsequent invocations when /data is found already populated with FreeIPA server configuration and data, the options are ignored and just the necessary services started in the container.

If you have existing container with data volume, it should be safe to shut it down and run new one based on newer image, with the same data directory bind-mounted to /data. The container logic will detect that it is running with data produced by different image and attempt to upgrade the configuration and data. Of course, keeping backup of the data directory for cases when the upgrade process fails is recommended.

Backup and restore

Speaking of backups: the FreeIPA server container stores all configuration, data, and logs in one volume mounted at /data. So instead of using ipa-backup and ipa-restore, the easiest way to backup the container is to stop it and just backup the content of the directory mounted to /data.

If you transfer that backup to different machine and you've been using setup with user namespace remapping (rootless containers), check that the /etc/subuid and /etc/subgid values used by the docker/podman match on both machines.

You then restore the server by running a new container with a copy of that backup mounted to /data.

Other runtime considerations

If you receive error like

IPv6 stack is enabled in the kernel but there is no interface that
has ::1 address assigned. Add ::1 address resolution to 'lo' interface.
You might need to enable IPv6 on the interface 'lo' in sysctl.conf.

you might also need to add option --sysctl net.ipv6.conf.all.disable_ipv6=0.

If you receive error like

Unable to determine the amount of available RAM

you might need to use ipa-server-install option --skip-mem-check.

When running DNS server (the --setup-dns argument to ipa-server-install) in a container with read-only root filesystem (the --read-only option to podman run or docker run), the setup code in the container won't be able to edit /etc/resolv.conf in the container to point it to itself. Add --dns=127.0.0.1 option to the podman run or docker run invocation to allow the FreeIPA server to reach its own DNS server.

To allow for unprivileged container operation, use the -h ... option to set the hostname for the FreeIPA server in the container. If it's not possible to set the hostname for the container, specify it with IPA_SERVER_HOSTNAME environment variable, for example with podman run -e IPA_SERVER_HOSTNAME=.... This might however not work with read-only containers. Do not use the ipa-server-install --hostname ... argument.

Exposing ports

If you want to use the FreeIPA server not just from the host where it is running but from external machines as well, you might want to use the -p options to make the services accessible externally.

docker run -p 53:53/udp -p 53:53 \
    -p 80:80 -p 443:443 -p 389:389 -p 636:636 -p 88:88 -p 464:464 \
-p 88:88/udp -p 464:464/udp -p 123:123/udp ...

You will then likely want to also specify the --ip-address option to ipa-server-install with the IP address of the host, and also use the --add-host option to the docker run / podman run with the same IP address, especially when running the container as read only.

Alternatively, the IPA_SERVER_IP environment variable via the -e option to docker run / podman run can be used to define what IP address should the FreeIPA server put to DNS as its address. Using this mechanism will however not update the ipa-ca record.

Debugging

The container scripts provide some options for debugging:

Enable shell script tracing in both the top-level init-data script and the ipa-server-configure-first script by setting the $DEBUG_TRACE environment variable.
Disable container exit after script failure by setting the $DEBUG_NO_EXIT environment variable. After failure, the container will continue running, and can be entered for debugging with e.g. podman exec -it freeipa-server-container bash. This can also be achieved by specifying no-exit as the first word in the [opts] to the container.
Force container exit after successfully configuring the FreeIPA server by specifying exit-on-finished as the first word in the [opts] to the container.

Example usage:

podman run [...] -e DEBUG_TRACE=1 -e DEBUG_NO_EXIT=1 localhost/freeipa-server ...

docker run [...] localhost/freeipa-server exit-on-finished -U -r EXAMPLE.TEST

You can also try to run

docker=podman tests/run-partial-tests.sh Dockerfile

docker=docker tests/run-partial-tests.sh Dockerfile

which can uncover the general issues with running systemd in containers.

CI in GitHub Actions

To check the general health of the project, see https://github.com/freeipa/freeipa-container/actions where tests are run for various OS versions in the containers.

License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

freeipa / freeipa-container

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