erl_sshd

Wrapper around Erlang ssh module to make it easy to add an ssh shell to an Erlang node. Add erl_sshd as rebar dependency and add erl_sshd configuration to your release's sys.config file.

Requirements

• Erlang 17+

Using

Add erl_sshd as a dependency in your rebar.config file. Then follow the configuration instructions

Configuration

erl_sshd is configured via its application environment variables. You can set these in your release's sys.config file (see example).

The port environment variable is the listener port number.

The app environment variable is the name of the application that is using erl_sshd as a dependency. erl_sshd looks in the priv directory of this application for the system key and authorized keys file.

You can use security keys and/or usernames and passwords to gain access to the shell.

Using keys

The host key and the authorized_keys file holding the user authorized keys are in priv/erl_sshd.

You can generate keys with:

% deps/erl_sshd/makekeys

This creates a system key as priv/erl_sshd/ssh_host_rsa_key, a public and private user key in the top directory, and a authorized keys file as priv/erl_sshd/authorized_keys. The authorize keys file contains the generated public user key.

You may also copy your own keys into the authorized_keys file.

From the top level you can connect to your node using:

% ssh hostname -p 11122 -i id_rsa

Using usernames and passwords

Follow the instructions above to create keys. The username/password authentication requires a system key to identify the host.

The passwords environment variable is a list of two element tuples where the first element is the username and the second element is the password. These are strings. For example:

{passwords, [{"lincx","nbv123"}]}

allows the user lincx to connect with the password nbv123.

Example

[
  {erl_sshd, [
                {app, dobby},
                {port, 11122},
                {passwords, [{"lincx","nbv1234"},
                             {"bobs","youruncle"}]}
             ]},
  ... % environment variables for other applications in the node
].