Document network, file structure, monitoring, auto-updates

README.md

@@ -48,6 +48,10 @@ Ensure the following software (or newer) is installed:
 
 We recommend to install Docker(-compose) from its official sources as described on the [Docker website](https://docs.docker.com). Note for Ubuntu: Please note that snap versions of Docker are not supported.
 
+### Network
+
+Since it needs to carry sensitive patient data, Bridgeheads are intended to be deployed within your institution's secure network and behave well even in networks in strict security settings, e.g. firewall rules. The only connectivity required is an outgoing HTTPS proxy. TLS termination is supported, too (see [below](#tls-terminating-proxies))
+
 ## Deployment
 
 ### Base Installation
@@ -107,6 +111,39 @@ sudo systemctl [enable|disable] bridgehead@<PROJECT>.service
 
 Even within your internal network, the Bridgehead enforces HTTPS for all services. During the installation, a self-signed, long-lived certificate was created for you. To increase security, you can simply replace the files under `/etc/bridgehead/traefik-tls` with ones from established certification authorities such as [Let's Encrypt](https://letsencrypt.org) or [DFN-AAI](https://www.aai.dfn.de).
 
+### TLS terminating proxies
+
+All of the Bridgehead's outgoing connections are secured by transport encryption (TLS) and a Bridgehead will refuse to connect if certificate verification fails. If your local forward proxy server performs TLS termination, please place its CA certificate in `/etc/bridgehead/trusted-ca-certs` as a `.pem` file, e.g. `/etc/bridgehead/trusted-ca-certs/mylocalca.pem`. Then, all Bridgehead components will pick up this certificate and trust it for outgoing connections.
+
+### File structure
+
+- `/srv/docker/bridgehead` contains this git repository with the shell scripts and *project-specific configuration*. In here, all files are identical for all sites. You should not make any changes here.
+- `/etc/bridgehead` contains your *site-specific configuration* synchronized from your site-specific git repository as part of the [base installation](#base-installation). To change anything here, please consult your git repository (find out its URL via `git -C /etc/bridgehead remote -v`).
+  - `/etc/bridgehead/<PROJECT>.conf` is your main site-specific configuration, all bundled into one concise config file. Do not change it here but via the central git repository.
+  - `/etc/bridgehead/<PROJECT>.local.conf` contains site-specific parameters to be known to your Bridgehead only, e.g. local access credentials. The file is ignored via git, and you may edit it here via a text editor.
+  - `/etc/bridgehead/traefik-tls` contains your Bridgehead's reverse proxies TLS certificates for [HTTPS access](#https-access).
+  - `/etc/bridgehead/pki` contains your Bridgehead's private key (e.g., but not limited to Samply.Beam), generated as part of the [Samply.Beam enrollment](#register-with-samplybeam).
+  - `/etc/bridgehead/trusted-ca-certs` contains third-party certificates to be trusted by the Bridgehead. For example, you want to place the certificates of your [TLS-terminating proxy](#network) here.
+
+Your Bridgehead's actual data is not stored in the above directories, but in named docker volumes, see `docker volume ls` and `docker volume inspect <volume_name>`.
+
+## Things you should know
+
+### Auto-Updates
+
+Your Bridgehead will automatically and regularly check for updates. Whenever something has been updates (e.g., one of the git repositories or one of the docker images), your Bridgehead is automatically restarted. This should happen automatically and does not need any configuration.
+
+If you would like to understand what happens exactly and when, please check the systemd units deployed during the [installation](#base-installation) via `systemctl cat bridgehead-update@<PROJECT>.service` and `systemctl cat bridgehead-update@<PROJECT.timer`.
+
+### Monitoring
+
+To keep all Bridgeheads up and working and detect any errors before a user does, a central monitoring 
+
+- Your Bridgehead itself will report relevant system events, such as successful/failed updates, restarts, performance metrics or version numbers.
+- Your Bridgehead is also monitored from the outside by your network's central components. For example, the federated search will regularly perform a black-box test by sending an empty query to your Bridgehead and checking if the results make sense.
+
+In all monitoring cases, obviously no sensitive information is transmitted, in particular not any patient-related data. Aggregated data, e.g. total amount of datasets, may be transmitted for diagnostic purposes.
+
 ## Troubleshooting
 
 ### Docker Daemon Proxy Configuration