docker-documentation/FAQ.md

# FAQ

Here will some Frequently Asked Questions reside

## My host is incompatible with images based on Ubuntu Jammy {#jammy}

Some x86_64 hosts running older versions of the Docker engine are not compatible with some images based on Ubuntu Jammy.

### Symptoms

If your host is affected you may see errors in your containers such as:

```shell
ERROR - Unable to determine java version; make sure Java is installed and callable
```

Or

```shell
Failed to create CoreCLR, HRESULT: 0x80070008
```

Or

```shell
WARNING :: MAIN : webStart.py:initialize:249 : can't start new thread
```

### Resolution

#### Option 1 (Long-Term Fix)

Upgrade your Docker engine install to at least version `20.10.10`. [Refer to the official Docker docs for installation/update details.](https://docs.docker.com/engine/install)

#### Option 2 (Short-Term Fix)

For Docker CLI, run your container with:

`--security-opt seccomp=unconfined`

For Docker Compose, run your container with:

```yaml
    security_opt:
      - seccomp=unconfined
```

## My host is incompatible with images based on rdesktop {#rdesktop}

Some x86_64 hosts have issues running rdesktop based images even with the latest docker version due to syscalls that are unknown to docker. 

### Symptoms

If your host is affected you may see errors in your containers such as:

```shell
Failed to close file descriptor for child process (Operation not permitted)
```

### Resolution

For Docker CLI, run your container with:

`--security-opt seccomp=unconfined`

For Docker Compose, run your container with:

```yaml
    security_opt:
      - seccomp=unconfined
```

## My host is incompatible with images based on Ubuntu Focal and Alpine 3.13 and later {#libseccomp}

This only affects 32 bit installs of distros based on Debian Buster.

This is due to a bug in the libseccomp2 library (dependency of Docker itself), which is fixed. However it's not pushed to all the repositories.

[A GitHub issue tracking this](https://github.com/moby/moby/issues/40734)

You have a few options as noted below. Options 1 is short-term, while option 2 is considered the best option if you don't plan to reinstall the device (option 3).

### Resolution

If you decide to do option 1 or 2, you should just need to restart the container after confirming you have libseccomp2.4.4 installed.

If 1 or 2 did not work, ensure your Docker install is at least version 20.10.0, [refer to the official Docker docs for installation.](https://docs.docker.com/engine/install/debian/)

#### Option 1

Manually install an updated version of the library with dpkg.

```bash
wget http://ftp.us.debian.org/debian/pool/main/libs/libseccomp/libseccomp2_2.4.4-1~bpo10+1_armhf.deb
sudo dpkg -i libseccomp2_2.4.4-1~bpo10+1_armhf.deb
```

{% hint style="info" %}
This url may have been updated. Find the latest by browsing [here](http://ftp.us.debian.org/debian/pool/main/libs/libseccomp/).
{% endhint %}

#### Option 2

Add the backports repo for DebianBuster. As seen [here](https://github.com/linuxserver/docker-jellyfin/issues/71#issuecomment-733621693).

```bash
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 04EE7237B7D453EC 648ACFD622F3D138
echo "deb http://deb.debian.org/debian buster-backports main" | sudo tee -a /etc/apt/sources.list.d/buster-backports.list
sudo apt update
sudo apt install -t buster-backports libseccomp2
```

#### Option 3

Reinstall/update your OS to a version that still gets updates.

* Any distro based on DebianStretch does not seem to have this package available
* DebianBuster based distros can get the package trough backports, as outlined in point 2.

{% hint style="info" %}
RaspberryPI OS (formerly Raspbian) Can be upgraded to run with a 64bit kernel
{% endhint %}

### Symptoms

* 502 errors in __Jellyfin__ as seen in [linuxserver/docker-jellyfin#71](https://github.com/linuxserver/docker-jellyfin/issues/71)
* `Error starting framework core` messages in the docker log for __Plex__. [linuxserver/docker-plex#247](https://github.com/linuxserver/docker-plex/issues/247)
* No WebUI for __Radarr__, even though the container is running. [linuxserver/docker-radarr#118](https://github.com/linuxserver/docker-radarr/issues/118)
* Images based on our Nginx base-image(Nextcloud, SWAG, Nginx, etc.) fails to generate a certificate, with a message similar to `error getting time:crypto/asn1/a_time.c:330`
* `docker exec <container-name> date` returns 1970

## I want to reverse proxy a application which defaults to https with a selfsigned certificate {#strict-proxy}

### Traefik {#strict-proxy-traefik}

In this example we will configure a serverTransport rule we can apply to a service, as well as telling Traefik to use https on the backend for the service.

Create a [ServerTransport](https://doc.traefik.io/traefik/routing/services/#serverstransport_1) in your dynamic Traefik configuration, we are calling ours `ignorecert`.

```yml
    http:
    serversTransports:
        ignorecert:
            insecureSkipVerify: true
```

Then on our `foo` service we tell it to use this rule, as well as telling Traefik the backend is running on https.

```yml
    - traefik.http.services.foo.loadbalancer.serverstransport=ignorecert
    - traefik.http.services.foo.loadbalancer.server.scheme=https
```