Yeah the server install instructions are a bit out of date it seems. It doesn't mention you need to run the 'make webapp' task to run webpack and generate the bundled HTML page. It also has you download an old version (0.5) and the docs on the config don't match what's in the repo now (with version 0.6.1).

Anyways, here's a Dockerfile I whipped up that builds and runs a local version configured to use sqlite. No nginx or other stuff, it's just simple localhost config (not production ready):

  # Focalboard v0.6.1 requires node 10+
  FROM node:15-buster-slim
  
  # Focalboard source to clone.
  ARG FOCALBOARD_REPO="https://github.com/mattermost/focalboard.git"
  ARG FOCALBOARD_BRANCH="v0.6.1"
  
  # Focalboard v0.6.1 requires make.
  RUN apt-get update && apt-get install -y \
        gcc \
        git \
        make \
  &&  rm -rf /var/lib/apt/lists/*
  
  # Focalboard v0.6.1 requires go 1.15+
  COPY --from=golang:1.16-buster /usr/local/go /usr/local/go
  ENV PATH="/usr/local/go/bin:$PATH"
  
  # Clone focalboard.
  WORKDIR /opt/focalboard
  RUN git clone --depth 1 --branch $FOCALBOARD_BRANCH $FOCALBOARD_REPO .
  
  # Build focalboard.
  RUN make prebuild \
  &&  make webapp \
  &&  make
  
  # Setup a localhost configuration with sqlite.
  RUN echo '{\
    "serverRoot": "http://localhost:8000",\n\
    "port": 8000,\n\
    "dbtype": "sqlite3",\n\
    "dbconfig": "/data/focalboard.db",\n\
    "useSSL": false,\n\
    "webpath": "./webapp/pack",\n\
    "filespath": "/files",\n\
    "telemetry": true,\n\
    "session_expire_time": 2592000,\n\
    "session_refresh_time": 18000,\n\
    "localOnly": false,\n\
    "enableLocalMode": true,\n\
    "localModeSocketLocation": "/var/tmp/focalboard_local.socket"\n\
  }' > /opt/focalboard/config.json
  
  # Uploaded files are stored here.
  VOLUME /files
  
  # Sqlite database is stored here.
  VOLUME /data
  
  CMD ["/opt/focalboard/bin/focalboard-server"]

It will need a volume at /files for uploaded file storage, and /data for its sqlite database. It exposes a server on port 8000, and an admin API unix socket on /var/tmp/focalboard_local.socket (read their docs for what it's useful for, like resetting passwords). The Dockerfile should be multiarch, but I can only test on amd64. Low spec hardware (raspberry pi) might struggle a bit with the build as it's a non-trivial go server build, and then production webpack bundle... weird failures might be OOM issues.

Here's an example of a basic build and run, saving the files and db to a local directory:

  
  docker build -t focalboard .
  docker run --rm -p 8000:8000 -v $PWD/files:/files -v $PWD/data:/data focalboard

Access http://localhost:8000 and it will let you create a new user account.

(go wild with the Dockerfile above, I release it in public domain)