Add FAQ

Starting with libseccomp2 shenanigans

FAQ.md

@@ -0,0 +1,42 @@
+# FAQ
+
+Here will some Frequently Asked Questions reside
+
+## My host is incompatible with images based on Ubuntu Focal
+
+This seems to only affect armhf.
+
+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, some are short-term.
+
+1. Use another tag, not based on Focal. At the time of writing we currently offer a `bionic` tag for [Plex](https://github.com/linuxserver/docker-plex) and [Jellyfin](https://github.com/linuxserver/docker-jellyfin) that will recive the same care as latest for the foreseeable future.
+
+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 install -t buster-backports libseccomp2
+    ```
+
+3. Manually install a 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 -o libseccomp2.deb
+    sudo dpkg -i libseccomp2.deb
+    ```
+
+    Note this url may have been updated. Find the latest by browsing [here](http://ftp.us.debian.org/debian/pool/main/libs/libseccomp/).
+
+4. 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.
+
+Symptoms of this can be:
+
+* 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)
+* `docker exec <container-name> date` returns 1970

SUMMARY.md

@@ -144,3 +144,5 @@
 * [linuxserver/wireguard](images/docker-wireguard.md)
 * [linuxserver/wireshark](images/docker-wireshark.md)
 * [linuxserver/znc](images/docker-znc.md)
+
+## [FAQ](FAQ.md)