Actions

Login to cluster

From ALICE Documentation

Revision as of 10:16, 8 July 2019 by Kosterj1 (talk | contribs)

To login to the ALICE cluster you need to perform a hop-like login sequence. The two login nodes of the ALICE cluster cannot be accessed directly. One must first login to an ssh gateway and then to one of the login nodes. This mechanism is required for both login and file transfer operations. Below we describe how to perform these actions from Linux and Windows, separately.

Login to ALICE from Linux

The login nodes are named:

login1.alice.universiteitleiden.nl (10.161.0.12)
login2.alice.universiteitleiden.nl (10.162.0.13)

Setup ssh JUMP

In your linux server write in ~/.ssh/config for instance

Host hpc1 
  HostName login1.alice.universiteitleiden.nl
  User <USERNAME>
  ProxyJump <USERNAME>@ssh-gw.leidenuniv.nl:22
  
Host hpc2
  HostName login2.alice.universiteitleiden.nl
  User <USERNAME>
  ProxyJump <USERNAME>@ssh-gw.leidenuniv.nl:22

(Replace <USERNAME> by your own ULCN account name.)

If you want to look at the monitoring tools that are running on the management node too, you could add additional tunneling commands to the config for a specific host. Do not add tunnels to all definitions as they may produce conflicts when you use the samen tunnel twice. So add the tunnel commands, for instance, to one host like:

Host hpc1tunnel
  HostName login1.alice.universiteitleiden.nl
  User <USERNAME>
  ProxyJump <USERNAME>@ssh-gw.leidenuniv.nl:22
  LocalForward 8081:management.alice.universiteitleiden.nl:8081
  LocalForward 8080:management.alice.universiteitleiden.nl:443

Alternatively, if your openssh server isn't that recent and doesn't recognize the ProxyJump alias, try this:

Host hpc1 
  HostName login1.alice.universiteitleiden.nl
  ForwardX11 yes
  User <USERNAME>
  ProxyCommand ssh -X <USERNAME>@sshgw.leidenuniv.nl -W %h:%p

Login to ssh-gw.leidenuniv.nl (ssh <USERNAME>@ssh-gw.leidenuniv.nl) and put your public key in

~/.ssh/authorized_keys

Login through to the HPC login1 node ''ssh login1.alice.universiteitleiden.nl' and put the same public key in

~/.ssh/authorized_keys

Direct login to login node 1

 ssh hpc1

and you can even forward X11 now.

File transfer to login node 1

 ssh <local_file_name> hpc1:<remote_file_name>

this copies the <local_file_name> file to <remove_file_name> file in your home directory on ALICE.

Tunneling to monitors

Having setup the ssh tunneling required to access the monitoring tools on the cluster you are now able to access port 443 (general secure web server on the management node) and port 8081 (specific port in use by the Bright Cluster Manager monitoring tools).

So in a browser you could type:

https://localhost:8080

to gain access to the management main web server, or you could type:

https://localhost:8081/userportal

to gain access to the Bright Cluster Manager User Portal.

Login to ALICE from Windows

Windows users can make use of the program PuTTY to log on to ALICE. In order for PuTTY to correctly handle tunnels we have to setup two login sessions. The first PuTTY session opens a login to the ssh gateway and sets up a tunnel to allow login to an ALICE login node directly from your Windows desktop. Once this gateway login session is running you can define a second PuTTY session to login one of the ALICE login nodes and define tunnels for that session, for whatever purpose you need.

Setup putty configuration

Open the configuration and create a saved session:

* Host Name: enter the gateway to which you first have to log in: sshgw.leidenuniv.nl
* Saved Sessions: use a name that you can remember, e.g.: ALICE_GW
* Click Save
Putty1a.jpg


Then go to the SSH tab/Tunnels and fill in the tunnels to the ALICE login 1 and login 2 nodes:

Putty2a.jpg

These two definitions allow you to setup two other sessions, one to login node 1 and one to login node 2.

Let's create the definition for the login node 2:

Putty3.jpg

Fill in as Host Name the tunnel information created in the ALICE_GW definitions: localhost or 127.0.0.1 and use port 2221 for login node 1 and 2222 for login node 2.

Now setup the tunnel definitions for anything you need:

Putty4.jpg

In this case we setup a tunnel to the WEBserver of the management node. This will allow us to open a browser on your windows desktop with the URL: https://localhost:8080.
Save the configuration under a name that you can remember: ALICE_login1

Login and use tunnels

  • Now open the first configuration ALICE_GW and login to the gateway.
  • Second, open the second configuration ALICE_login1 and login to the ALICE login node 1.
  • Then you can perform your operations on login node 1 and also inspect the webpages from the management node web server directly from your desktop.