Running Cells behind an Apache reverse proxy

Created on 2021/01/28, apache, cells, configuration, reverse-proxy, ssl

In this tutorial, we shortly present a basic setup to use an Apache webserver as reverse proxy in front of a Pydio Cells installation.

Cells Sync will not be able to work with apache2, apache is currently not completely supporting gRPC.

You can still use apache for the webUI, but if you wish to use Cells Sync you must also run another reverse proxy solely for the sync (read chapter at the end).

Specific Pydio Cells Configuration

During the installation process, instead of the default settings, enter a configuration similar to this:

Bind Address:
External URL:

To configure the external URL on cells, run the following command:

./cells configure sites
  • Bind Address: interface and port on which Cells server is bound. It MUST contain a server name and a port.
  • External URL: the end user will use to connect to the application, (in this case the external is the reverse proxy, because it will be used to access Cells)
  • Protocol: if you are using SSL, the external host must be starting with https:// (you don't need to specify the port)
  • Example:

Assuming that your reverse proxy is running alongside Cells, on localhost on port 8080. then set the bind address to localhost:8080 and external address to

Configure Apache

You must enable the following mods with apache :

  • proxy
  • proxy_http
  • proxy_wstunnel

sudo a2enmod **modname**

A simple example

For this example, we are using a very simple setup. The proxy is running on a server with this IP (or domain, while Pydio Cells is running on another server with IP and listening at port 8080.

Edit Apache mod_ssl configuration file to have this:

Listen 8080
<VirtualHost *:8080>

  AllowEncodedSlashes On
  RewriteEngine On
  #SSLProxyEngine On
  #SSLProxyVerify None
  #SSLProxyCheckPeerCN Off
  #SSLProxyCheckPeerName Off

  #Proxy WebSocket
  #RewriteCond %{HTTP:Upgrade} =websocket [NC]
  #RewriteRule /(.*) wss://$1 [P,L]
  ProxyPassMatch "/ws/(.*)" ws://$1 nocanon
  # for ssl
  # ProxyPassMatch "/ws/(.*)" wss://ip.or.domain.server/ws/$1 nocanon

  # Collabora Online
  # ProxyPassMatch "/lool/(.*)ws$" wss://*1/ws nocanon

  # Onlyoffice
  # ProxyPassMatch "/onlyoffice/(.*)/websocket$" ws://$1/websocket nocanon

  #Finally simple proxy instruction
  ProxyPass "/" "" nocanon
  ProxyPassReverse "/" "" nocanon

  #Uncomment if you are going to use SSL
  #SSLEngine on
  #SSLCertificateFile /etc/ssl/localcerts/server.crt
  #SSLCertificateKeyFile /etc/ssl/localcerts/server.key
  #SSLCertificateChainFile /etc/ssl/localcerts/bundled.crt

  ErrorLog ${APACHE_LOG_DIR}/error-ssl.log
  CustomLog ${APACHE_LOG_DIR}/access-ssl.log combined

Important points

Please note:

  • The AllowEncodedSlashes enabled, may be necessary if not activated globally in Apache. It enables API calls like /a/meta/bulk/path%2F%to%2Ffolder.
  • When configuring Cells, even on another port, make sure to bind it directly to the as well (like Apache). This is necessary for the presigned URL used with S3 API for uploads and downloads (they used signed headers and a mismatch between received Host headers may break the signature). Another option is to still bind Cells using a local IP, then in the Admin Settings, under Configs Backend, use the field “Replace Host Header for S3 Signature” and use the internal IP here.
  • nocanon is required after the ProxyPass to be able to download files that contains special characters such as commas/quotes.
  • websocket make sure to proxy the websocket depending on your protocol (ws, or wss).

Cells Sync

Unfortunately apache does not seem to completely support gRPC therefore you probably will need to use another software to reverse proxy the gRPC part (tied to the Cells Sync desktop application).

  • You are running Cells with SSL (can be self_signed).
  • You have set the port with the following env variable CELLS_GRPC_EXTERNAL=33060.

Note: the port defined for the gRPC can use any value.

Caddy webserver

You can run caddy with the following configuration: {
    tls /etc/letsencrypt/cells/fullchain.pem /etc/letsencrypt/cells/privkey.pem
    log stdout
    errors stdout

    proxy / {


You can run nginx with the following configuration, which will allow you to connect with grpc and use the Sync desktop application.

server {
    listen 33060 ssl http2;
    listen [::]:33060 ssl http2;
  ssl_protocols       TLSv1 TLSv1.1 TLSv1.2;
  ssl_ciphers         HIGH:!aNULL:!MD5;
    keepalive_timeout 600s;

    location / {
        grpc_pass grpcs://;

  error_log /var/log/nginx/proxy-grpc-error.log;
  access_log /var/log/nginx/proxy-grpc-access.log;

See Also

Running Cells Behind a reverse proxy