# Login

```{questions}
- How to reach UPPMAX clusters?
- Where do I arrive when I log in? Login or calculation node?
- What clients should/could I use for my work at UPPMAX?
- How can I enable graphics?

```

```{objectives}
- We'll go through platform specific (Mac/Linux/Windows) ways to log in to UPPMAX
- See different clients
- Enable graphics
- Try yourself!
```

```{note}
If you lack a user account, visit the [Getting started page](https://www.uppmax.uu.se/support/getting-started/course-projects/)
```

## The login

```{discussion} Login procedure
   **Which login procedure is best for You, depends on:**
   - Your background
   - Your OS environment,
   - Your planned interaction with your local computer
   - Your planned use of graphics on the cluster
```


```{admonition} Login procedure
   If you plan to:
   - do **day-to-day** work where *terminal shell is sufficient*
     - Mac: *Terminal, iTerm2*
     - Linux: *Terminal*
     - Windows: *Putty*, *Windows Powershell* or even *command prompt (CMD)*
     
     
   - **interact with you local computer**
     - Mac/Linux: you can always work in a local shell (mutiple terminal windows open)
        - (S)FTP browser: *Filezilla*, *Cyberduck*
     - Windows
        - (S)FTP browser: *WinSCP*
        - *MobaXterm* has built-in SFTP browser
        - you may benefit from having a *Windows Subsystem for Linux, WSL(2)*
        
        
   - **do day-to-day work** with **some graphical applications (X forwarding)**
     - Mac: *Terminal, iTerm2 + XQuartz*
     - Linux: *Terminal*
     - Windows: *MobaXterm*
     
     
   - integrate you cluster work with **code development**
     - All OS: Example *Visual Studio Code*
     
     
   - use **sophistic graphical interfaces** like *RStudio and MATLAB* etcetera
     - *ThinLinc application*
     
     
   - use **Bianca**
     - *ThinLinc from web*
   
```

## General understanding

- When logging in to UPPMAX from your local computer you will arrive to your home folder at the login node.
- This means that only light analysis and and calculations should be made here.
- You will see this in the prompt after "@" as the clustername and a low number. For instance:
   ```console
      [<user>@rackham3 linux_tutorial]$
    ```
- You will later learn how to reach the calculation nodes. Then the prompt states the node number with a single letter, like "r" for Rackham. For instance:
   ```console
      [<user>@r484 linux_tutorial]
   ```

## Terminals 

`````{tabs} 
````{tab} Mac

- Start terminal (e.g. from Launchpad) or [iTerm2](https://iterm2.com/)
```{code-block} console
$ ssh <username>@rackham.uppmax.uu.se
```
- "< >" prompts you to set the keyword specific for you or your needs. In the example above, this is basically your username.

![Terminal](./img/Mac_terminal.png)
- iTerm2 goodies:
  - You can save hosts for later.
  - Drag and drop scp

````

````{tab} Windows

- Start terminal (see below)
```console
$ ssh <username>@rackham.uppmax.uu.se
```
- "< >" prompts you to set the keyword specific for you or your needs. In the example above, this is basically your username.

![Terminal](./img/putty.jpg)

- the ssh (secure shell) client [**putty**](https://www.putty.org/) is sufficient first days of the course!

    - You can save hosts for later.
    - No graphics.
    
- Windows Powershell terminal can also work

    - Cannot save hosts
    - no graphics
    - [PowerShell](https://learn.microsoft.com/en-us/powershell/)
    
- Windows command prompt can also work

    - Cannot save hosts
    - no graphics
    - [Command Prompt](https://www.makeuseof.com/tag/a-beginners-guide-to-the-windows-command-line/)

- [Git bash](https://gitforwindows.org/)

````
`````

## Terminal with X11 server and light graphics

`````{tabs} 
````{tab} Mac

- Download XQuartz or other X11 server for Mac OS
  - [https://www.xquartz.org/](https://www.xquartz.org/)

- Start terminal (e.g. from Launchpad) or [iTerm2](https://iterm2.com/)

```console
$ ssh -Y <username>@rackham.uppmax.uu.se
```
- ``-X``      Enables X11 forwarding. 
- ``-Y``      Enables trusted X11 forwarding

````

````{tab} Windows

- Download and install ONE of the X-servers below (to enable graphics)
  - [GWSL](https://opticos.github.io/gwsl) (recommended because of hardware integration)
  - [X-ming](https://sourceforge.net/projects/xming/)
  - [VCXSRV](https://sourceforge.net/projects/vcxsrv/) 


- or... 
- Install a ssh (secure shell) program with built-in X11 and sftp file manager
  - [**MobaXterm**](https://mobaxterm.mobatek.net/)
    - sftp frame makes it easy to move, upload and download files.
    - ... though downloading from remote host to local is usually easier.
    - tabs for several sessions

![Caption](./img/mobax.jpg )

- Start local terminal and a SSH session by:

```console
$ ssh -Y <username>@rackham.uppmax.uu.se
```

![Caption](./img/mobax_start1.jpg)

- Or even better, create and save a SSH session, as shown in image below.
  - This allows you to use MobaXterm as a file manager and  to use the built-in graphical texteditor.
  - You can rename the session in the Bookmark settings tab.

![Caption](./img/mobax_start.jpg)


````
`````

```{admonition} X11-forwarding from the command line (generally)

- Graphics can be sent through the SSH connection you’re using to connect
  - Use primarily `ssh -Y <...>` or secondary `ssh -X <...>`

- The X servers that enables graphics are needed, as mentioned above!
  - When starting a graphical program, a new window will open, but your terminal will be “locked”.
  - Run using "`&`" at the end to run it as a background process e.g. "`xeyes &`" or “`gedit &`”

![Caption](./img/xeyes.png)

- Alternatively, use `<ctrl>-z` to put e.g. gedit to sleep and type "`bg`" to make last process in background.
```


``````{challenge} Login to **Rackham**, using your terminal
- First try:
```console
$ ssh -Y <username>@rackham.uppmax.uu.se
```
- If you receive errors or warnings, instead try:
```console
$ ssh <username>@rackham.uppmax.uu.se
```
- If you do have X11 installed:
```console
$ xeyes &
```
``````

## Graphical file manager

- This is good if you want to move many files between host and local and cannot use wildcards.

`````{tabs} 
````{tab} Mac

- For copying of files with sftp (secure file transfer protocol) between your client computer (where you are) and the cluster **Filezilla** can be the choice.
- [Filezilla](https://filezilla-project.org/download.php?type=client)
 

![Caption](./img/fz3_osx_main.png )

- [Cyberduck](https://cyberduck.io/)

````

````{tab} Windows

- For copying of files between your client computer (where you are) and the cluster **WinSCP** can also be the choice.
  - [https://winscp.net/eng/download.php](https://winscp.net/eng/download.php) 

- ![Caption](./img/WinSCP.png )

- [Cyberduck](https://cyberduck.io/)

- [Filezilla](https://filezilla-project.org/download.php?type=client)

```` 
`````

```{callout} Problems with installations?
Putty/Terminal  without X11 is sufficient first days of the course!
```


## Linux on your computer

```{admonition} Local Linux environment
   - You may sometimes benefit from having a local Linux environment.
   - Examples:
     - Mimic cluster environment to work with your local files and data as on the Cluster
     - get used to Linux (!)
   - Mac is UNIX and very Linux-like
   - Windows requires WSL (Windows subsystem for Linux)
```

```{solution} For windows users who wants to get started with WSL (not covered here)
- Install WSL (Windows Subsystem for Linux) 
    - https://docs.microsoft.com/en-us/windows/wsl/install-win10 (Links to an external site.)
    - Don’t forget to update to wsl2
- Install a distribution or a ssh (secure shell) program
  - Distribution such as ubuntu or
  - (recommended) a ssh program such as MobaXTerm
  - https://mobaxterm.mobatek.net/ (Links to an external site.)
    - sftp frame makes it easy to move, upload and download files.
- You may want to check this webpage as well!
  - https://hackmd.io/@pmitev/Linux4WinUsers (Links to an external site.)
```
 
## Visual Studio Code (not covered in course)

- Intergrate you cluster work with *code development*
- [SSH-remote from VS Code](https://code.visualstudio.com/docs/remote/remote-overview)
- [Remote development using Visual Studio Code on Alvis cluster](https://www.c3se.chalmers.se/documentation/remote-vscode/remote_vscode/) 
  - Similar to Rackham. Just change login details!

 
## ThinLinc (all platforms!)

- Both Rackham and Bianca offer graphical login.
- This gives you a desktop environment, as if you were working on your own computer!
- On web:
  - [https://rackham-gui.uppmax.uu.se](https://rackham-gui.uppmax.uu.se)
  - [https://bianca.uppmax.uu.se](https://bianca.uppmax.uu.se)
    - requires [2-factor authentication](https://www.uppmax.uu.se/support/user-guides/setting-up-two-factor-authentication/)

![Caption](./img/Thinlinc2.jpg)

 - Or use the client (only for Rackham)
   - [https://www.cendio.com/thinlinc/download](https://www.cendio.com/thinlinc/download)

```{challenge} Try Thinlinc from web
  - Try the web version now if you don't already have the software installed!
```

 ```{keypoints}
- When you log in from your local computer you will always arrive at a login node with limited resources. 
  - You reach the calculations nodes from within the login node (See  Submitting jobs section)
- You reach UPPMAX clusters either using a terminal client or Thinlinc
- Graphics are included in Thinlinc and from terminal if you have enabled X11.
- Which client to use?
  - Graphics and easy to use
    - ThinLinc
  - Best integrated systems
    - Visual Studio Code has several extensions (remote, SCP, programming IDE:s)
    - Windows: MobaXterm is somewhat easier to use.
  
```