NX FAQ

What Keys are used in NX at NERSC?

Two pairs of keys are used in NERSC NX service. 

1. The NX system key pair (NX Access Key). This is the key pair that allows the NX client to connect to the NX server. The private key is included in the downloadable configuration file and on the webpage. Note that NX client softwares will come with a default private key, so if you did not configure your client properly, you might see "Authrization Failed" error message. 

 2. The NERSC NX key pair. This key pair is only for NERSC. This key pair allows user to connect to different NERSC machines from inside NX, without typing the NIM password each time. The private key is installed on the nx.nersc.gov host, the public key is installed to the user's global home. If you experience any problem with this key pair, you can try to re-generate the key pair by choosing "SSH Agent"->"Regenerate Keypair".  

What Passwords are used in NX at NERSC?

Two passwords are related to the NERSC NX service:

1. Your NIM password. This is the password you will use to "LOGIN to NX", i.e. use it before you see the NX desktop. You can change this password at nim.nersc.gov

2. Password for your NERS NX Key pair (No.2 in the previous FAQ What Keys are used in NX at NERSC). You need to use this password when you click on the "NERSC Systems" menu INSIDE NX. To change this password, you need to choose "Regenerate Keypair" from the "SSH Agent" menu inside NX. 

How to Manually Kill a Frozen Session?

USE WITH CAUTION, this will kill one or more running sessions and all unsaved work will be lost.

1. Login to nx.nersc.gov

ssh NIM_username@nx.nersc.gov

2. Use ps to get a list of runing nxnode or nxagent agents

ps -ef|grep $USER|grep nxagent

ps -ef|grep $USER|grep nxnode

3. use kill to kill all of nxagent and nxnode processes

The 2nd field from the output of the ps commands above is the PID, to kill a process use 

kill -9 PID 

4. Try to connect again

 '~' key doesn't work on NX Player 4

After you've connected to a NERSC machine (e.g. carver/hopper), do: