Remote Access and Control of Cluster Machines¶
The NOvA DAQ cluster has been equipped with a remote console server and a set of remote controllable power distribution strip (PDU). This combination of devices allows for remote access to the cluster and the ability to remotely reset machines even when they are not responding to network logins.
Remote Console Access¶
Remote access to the consoles on each of the DAQ cluster machines can be had through one of three methods that the console server supports.
Direct Access via SSH¶
You can "ssh" to the console of any of the DAQ machines using the following incantation:
ssh -x -t root:email@example.com
You will be prompted for a password which corresponds to the root account's password on the terminal server.
For example to access the console for novadaq-farm-02 or to access the datamon machine you would try:
ssh -x -t root:firstname.lastname@example.org ssh -x -t root:email@example.com
Direct Access via telnet¶
For various reasons you may prefer to access the consoles via telnet. An example would be if you are already ssh into a machine from offsite and want to have two different esc sequences available to break you out of a session (if nesting ssh sessions, the outer one is the one that get's the esc sequence, so "~." would break you out of the top most session killing all others that are under it, while if you had an ssh->telnet chain then you could separately break from the telnet or ssh)
To reach the console in this manner use a port designation on the telnet command, where the port number is the 7000 + the local cable link number.
The following table shows the node and link assignment
So to directly access the data monitor console via telnet:
telnet novadaq-term-server.fnal.gov 7030
Access Via Web interface¶
It is also possible to access the consoles via a web client that is run off of the terminal server. To do this, open a web browser and point it at http://novadaq-term-server.fnal.gov/
Confirm the security exceptions and get the appropriate certificate. Then login as root and you will see an interface similar to:
Select the "Applications" tab, and you will see a menu that allows you to select a host to connect to
Select the host and hit connect. A java based terminal application will open up with a connection to the host.