README

# FreeIPA server container

This repository contains `Dockerfile`s 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

* https://quay.io/repository/freeipa/freeipa-server?tab=tags
* https://hub.docker.com/r/freeipa/freeipa-server/tags

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](https://docs.docker.com/engine/security/rootless/)
(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](https://docs.docker.com/engine/security/userns-remap/)
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.

By default the container will attempt to update the FreeIPA
server's IPv4 address in the internal DNS server to its internal
address (as seen in the container) upon each startup, using the
systemd service `ipa-server-update-self-ip-address` in the container.
You can disable this mechanism by setting the `IPA_SERVER_IP`
environment variable to `no-update`, via the `-e` option to
`docker run` / `podman run`, or by exec-ing to the container and running
`systemctl disable ipa-server-update-self-ip-address.service`.

Alternatively, the `IPA_SERVER_IP` environment variable can be
used to force the IPv4 address DNS record to a specific value.
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 ...

or

    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

or

    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.