Multi-visdom proxy

Objective: set up and use a proxy server that allows access to multiple visdom visualization instances through a single gate server. This is done through a nginx web server that redirects paths to running visdom instances. The nginx configuration is kept separate for each user of the server machine to avoid any conflict.

The multivisdom_setup.py script provides an interactive interface to add credentials as well to list, add or remove paths to visdom instances.

Setting up the proxy

We will call proxy server the server used as proxy, it needs to be accessible from the client browser. We will call visdom server the server that will be running visdom, it does not need to be accessible from the client browser.

Requirements

The proxy server needs to have nginx installed (it should be available from your package manager). To protect all pages with a password, we will need to have htpasswd installed. It is available in the apache2-utils package on Ubuntu for example. In this tutorial, we assume that the address of the proxy server is proxyserver:1234.

Configuration

You will need a user with write access to the nginx folder (sudoer in general, or normal user if you have a non-global nginx install).

• To initialize the nginx configuration (with port 1234 for our example): run sudo python multivisdom_setup.py --port 1234 (needs sudoer).
• To allow unprivileged users to reload nginx after they make changes, do the following steps:
  • Run sudo visudo
  • Go to last line and add: ALL ALL=NOPASSWD: /usr/sbin/service nginx reload and a comment # Allow all users to reload nginx. All users (even not sudoers) can now run sudo /usr/sbin/service nginx reload.

Usage of the proxy server

Requirements

You need to have visdom installed on the visdom server(s). In this tutorial, we assume that you have two visdom servers running on two different servers at visdomserv1:9087 and visdomserv2:9087.

Using the proxy

Run the multivisdom_setup.py script when logged in with your user name on the proxy machine.

Available actions:

• List all links for the current user.
• Add a link for the current user. You need to provide:
  • The path to access visdom on the proxy server. If you enter foo, you can access it at proxyserver:1234/username/foo
  • The hostname/ip of the server running visdom. In our example, that would be visdomserv1 or visdomserv2.
  • The port used for visdom. In our example, that would be 9087.
• Delete a link for the current user.
• Add a new login/password to connect to all links of the current user. You will need to use these to access all the pages corresponding to your user.