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Remote Desktop Access	NX, nomachine, remote desktop access, login node, login001, login002, merlin7-nx-01, merlin7-nx-02, merlin7-nx, rem-acc, VPN, browser access	07 August 2024	merlin7_sidebar	/merlin7/nomachine.html

Users can log in to Merlin through a Linux Remote Desktop Session. NoMachine is a desktop virtualization tool similar to VNC, Remote Desktop, etc. It uses the NX protocol to enable a graphical login to remote servers.

New Feature: Browser-Based Access

We have now enabled browser-based access to Merlin7. This allows users to connect to the NoMachine service directly through a web browser, removing the need to install a client application. This is accessible via the following URL:

• Browser Endpoint: https://merlin7-nx.psi.ch:4443

How to Connect via Browser

1. Open your web browser and navigate to https://merlin7-nx.psi.ch:4443.
2. Enter your credentials when prompted. Do not add PSICH\ as a prefix for the username.
3. Follow the on-screen instructions to launch a new session or reconnect to an existing one.

Installation

For traditional access, NoMachine is available for PSI Windows computers in the Software Kiosk under the name NX Client. Please use the latest version (at least 8.1.3). For macOS and Linux, the NoMachine client can be downloaded from https://www.nomachine.com/.

Accessing Merlin7 NoMachine from PSI

The Merlin7 NoMachine service is hosted on the following machine:

• merlin7-nx.psi.ch

This is the front-end (hence, the door) to the NoMachine back-end nodes, which contain the NoMachine desktop service. The back-end nodes are the following:

• login001.merlin7.psi.ch
• login002.merlin7.psi.ch

Any access to the login node desktops must be done through merlin7-nx.psi.ch.

The front-end service running on merlin7-nx.psi.ch will load-balance the sessions and log in to any available nodes in the back-end.

Only one session per back-end is possible.

Below are all the steps necessary for configuring access to the NoMachine service running on a login node.

Creating a Merlin7 NoMachine Connection

Adding a New Connection to the Front-End

Click the Add button to create a new connection to the merlin7-nx.psi.ch front-end, and fill up the following fields:

• Name: Specify a custom name for the connection. Examples: merlin7-nx, merlin7-nx.psi.ch, Merlin Desktop
• Host: Specify the hostname of the front-end service: merlin7-nx.psi.ch
• Protocol: Specify the protocol that will be used for the connection. Recommended protocol: NX
• Port: Specify the listening port of the front-end. It must be 4000 for the NX protocol.

![Create New NoMachine Connection]({{ "/images/NoMachine/screen_nx_connect.png" }})

Configuring NoMachine Authentication Method

Depending on the client version, it may ask for different authentication options. If required, choose your authentication method and Continue (Password or Kerberos are recommended).

You will be requested for the credentials (username/password). Do not add PSICH\ as a prefix for the username.

Opening NoMachine Desktop Sessions

By default, when connecting to the merlin7-nx.psi.ch front-end, a new session automatically opens if none exists.

If there are existing sessions, users can reconnect to an existing one instead of opening a new desktop session by clicking the appropriate icon (see image below).

![Open an existing Session]({{ "/images/NoMachine/screen_nx_existingsession.png" }})

Users can also create a second desktop session by selecting the New Desktop button (red rectangle in the image below). This will create a second session on the second login node as long as it is up and running.

![Open a New Desktop]({{ "/images/NoMachine/screen_nx_newsession.png" }})

NoMachine LightDM Session Example

An example of the NoMachine session, which is based on LightDM X Windows:

![NoMachine Session: LightDM Desktop]({{ "/images/NoMachine/screen_nx11.png" }})

Accessing Merlin7 NoMachine from Outside PSI

No Direct Access Without VPN

During the pre-production phase, direct access to the NoMachine service from outside the organization is not supported. To access the service, you must first connect to PSI's VPN. The external rem-acc.psi.ch service does not yet allow direct access to the new cluster without a VPN connection.

VPN Access

Remote access is possible through VPN; however, you must not use 'rem-acc.psi.ch', and you have to connect directly to the Merlin7 NoMachine merlin7-nx.psi.ch front-end as if you were inside PSI. For VPN access, you should request it from the IT department by opening a PSI Service Now ticket: VPN Access (PSI employees).

Advanced Display Settings

NoMachine Display Settings can be accessed and changed when creating a new session or by clicking the top right corner of a running session.

Prevent Rescaling

These settings prevent "blurriness" at the cost of some performance! (You might want to choose depending on performance)

• Display > Resize remote display (forces 1:1 pixel sizes)
• Display > Change settings > Quality: Choose Medium-Best Quality
• Display > Change settings > Modify advanced settings
  • Check: Disable network-adaptive display quality (turns off lossy compression)
  • Check: Disable client-side image post-processing