Serial port cascading allows access to up to 10000 clustered serial ports from a single console server. This is achieved by designating a master console server, from which all ports are configured and accessed, and one or many slave console servers.
The master establishes a persistent SSH tunnel to each of the slaves. The slaves' serial ports then become "cascaded ports" of the master.
Access to a cascaded port on the master is automatically and transparently redirected through the appropriate SSH tunnel, e.g. if the master has 48 ports, access to master port 49 redirects to port 1 of the first slave.
- Configure master and slave console servers with network settings (System -> IP)
- Login to the master as root or an admin group user
- Click System -> Administration
- Click Generate SSH keys automatically and Apply
- Check RSA Keys and Apply
- Wait a few minutes for keys to generate
- Upload your preferred SSH RSA Public & Private Key
- The IP Address/DNS Name to establish the SSH tunnel to
- An identifying Label and an optional Description
- The Number of Ports to cascade to this slave
- The Remote Root Password, used to install the master's public key in the slave's authorized keys file
- Click Apply
Now the cascaded/slave serial ports are displayed on the master in Serial & Network -> Serial Port.
Once configured in Console Server Mode, cascaded ports are accessible via the usual access methods.
- Cascading is incompatible with Lighthouse Central Management, which uses Console Gateway to aggregate console access
- Serial port settings on slave console servers must be configured from the master
- Users and groups on slave console servers must be configured from the master
- The Power Menu escape command is incompatible with cascaded ports
- Auto-Response is incompatible with cascaded ports
- Using IPv6, cascaded console port access via the master is available using the username:serial convention only
- Slave ports are cascaded from the master contiguously in the order that they were added, and cannot be reordered