# User Environment

## A. Account Creation

### 1. Researchers that have been approved to use the Nurion system should access the KSC website ([**https://www.ksc.re.kr**](https://www.ksc.re.kr/)) to apply for an account.

#### 1) How to apply : Access the KISTI website, (top) Application for use -> (top) Apply -> Select application

* Free account : Nurion system innovative support program, new users of the 5th supercomputer
* Paid account : General and student users of the 5th supercomputer
* Once an account has been created, information related to the account will be sent to the email listed on the application.

#### 2) Request for OTP (One Time Password) authentication code

**Based on the account information email you have received,** send an email to [account@ksc.re.kr](mailto:account@ksc.re.kr) by referring to the example below to receive an authentication code.

| Subject              | Request for an OTP authentication code – user ID           |
| -------------------- | ---------------------------------------------------------- |
| Recipient            | (example) Request for an OTP authentication code - x123abc |
| Email Body (example) | account@ksc.re.kr                                          |

#### 3) Installing OTP application

* The OTP smartphone application is provided for secured access to the supercomputer.
* For the OTP smartphone application, search for “Any OTP” on Google Play or App Store and install the application developed by Mirae-tech.
* When logging into the supercomputer, the OTP security code of the “Any OTP” application must be entered.
  * If you do not use a smartphone, please consult the account manager (account@ksc.re.kr).
  * Refer to the “OTP User Manual” by accessing the KISTI website > Technical Support > Guidelines for more details on OTP installation and use
    * Emails will be sent out for users on the LG U+ network because text messages are processed as spam on this network

## B. Login

* Users can gain access through the login node (nurion.ksc.re.kr) of the Nurion system (refer to the node configuration below).
  * By logging into MyKSC (KISTI Supercomputer Web Service Portal, https://my.ksc.re.kr) via a web browser, users can utilize GUI-based HPC and AI/data analysis services (refer to the MyKSC guide for instructions)
* Default character set (encoding) is in unicode (UTF-8).
* Only ssh, scp, sftp, and X11 are allowed to access the login node.

### 1. Unix or Linux environment

```shell-session
$ ssh -l <USER_ID> nurion.ksc.re.kr [-p 22]
```

* e.g.) When user ID is x123abc

```
$ ssh -l x123abc nurion.ksc.re.kr
or
$ ssh -l x123abc nurion.ksc.re.kr -p 22
```

### 2. Windows environment

* Run Xming to execute the X environment
  * Download the program for free from the internet and install it.

![](https://786944814-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYo7SdeOemdWmRfqMQaK6%2Fuploads%2Fgit-blob-680d2298a555d8a233b8368acd1d6060d34e9fd2%2FJJNmXayKPdXGask.png?alt=media)

* Use ssh access programs such as PuTTY or SSH Secure Shell Client
  * Host Name : nurion.ksc.re.kr, Port : 22, Connection type : SSH
  * Programs can be downloaded for free from the internet.

![](https://786944814-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYo7SdeOemdWmRfqMQaK6%2Fuploads%2Fgit-blob-1eb248ff64fc1cdcb18e2de5e810d19fbb6fba34%2FmymgSTp1SpIXNqv.png?alt=media)

* ssh -> X11 tap -> check "Enable X11 forwarding"
* X display location : localhost:0.0

![](https://786944814-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYo7SdeOemdWmRfqMQaK6%2Fuploads%2Fgit-blob-f28d0fe68c172e4a3446eb31b841d1efe8f87a07%2F7CIgfnisxwUP8q8.png?alt=media)

※ If the system cannot be accessed because of a DNS caching problem, clear all cache (run ipconfig/flushdns in command prompt) and access again.

```
C: ipconfig /flushdns
```

### 3. Sending/receiving files

* Files can be transferred to and from the Datamover node (nurion-dm.ksc.re.kr) using an FTP client via FTP or SFTP (refer to the node configuration below).

```shell-session
$ ftp nurion-dm.ksc.re.kr 
or 
$ sftp [user ID@] nurion-dm.ksc.re.kr [-p 22]
```

* In the Windows environment, use FTP/SFTP client programs such as WinSCP that are distributed for free to access the system.

![](https://786944814-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYo7SdeOemdWmRfqMQaK6%2Fuploads%2Fgit-blob-399dfe1612c94bc9c0a2dca6363c741a5e8453a5%2Fcmp2uAQLNNDJaOJ.png?alt=media)

* When using FTP (File Transfer Protocol), file transfers can be made without entering an OTP.
* When using SFTP (Secure FTP), it is required to enter OTP for file transfers. (SFTP is a more secure transfer method than FTP)

### 4. Node configuration

![](https://786944814-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYo7SdeOemdWmRfqMQaK6%2Fuploads%2Fgit-blob-e36646461a8a6c2ca7ba563f0eaa375cdfd245a0%2Fimage%20\(4\).png?alt=media)

* It is recommended to use the Datamover node, which has no CPU limit, for downloading via wget or git and for transferring large datasets (transfers on the login node may be interrupted due to CPU limits).
* File compression and decompression may also be interrupted due to CPU limits. If processes are forcibly stopped on the login node, perform compression/decompression on the Datamover node.

## C. Changing User Shell

* BASH is provided as the default shell for the login node of the Nurion system. The chsh command is used for changing to a different shell.

```shell-session
$ chsh
```

* echo $SHELL is used for checking the currently used shell.

```shell-session
$ echo $SHELL
```

* Change the configuration files (.bashrc, .cshrc, etc.) in the home directory of a user

## D. Changing User Password

* Use the passwd command in the login node to change a user’s password.

```shell-session
$ passwd
```

* &#x20;Password-related security policy
  * The user password must be at least 9 characters and include an alphabet, number, and special character. English words in the dictionary cannot be used.
  * The user password expiration period is two months (60 days).
  * The new password cannot be the same as the five previously used passwords.
  * Maximum number of incorrect login attempts : 5
    * The ID will get locked if you attempt to log in five times with the incorrect password; contact the account manager ([acccount@ksc.re.kr](mailto:acccount@ksc.re.kr)) when your account is locked.
    * The IP address of a PC will be temporarily blocked if you attempt to log in five times with the incorrect password; contact the account manager ([account@ksc.re.kr](mailto:account@ksc.re.kr)) if needed.
  * Maximum number of incorrect OTP authentication attempts : 5
    * Contact the account manager ([account@ksc.re.kr](mailto:account@ksc.re.kr)) if you have failed to authenticate five times.

## E. Checking SRU Time Usage of User Account

* Access the integrated supercomputer account managing system (ISAM) to check a user’s contract information, detailed batch job usage, and total SRU time usage.

```shell-session
$ isam
```

## F. Job Directory and Quarter Policy

* Users are provided with two file systems: a home directory (/home01/$USER) and a scratch directory (/scratch/$USER).

![](https://786944814-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYo7SdeOemdWmRfqMQaK6%2Fuploads%2Fgit-blob-97efa728f4d0afe5ee28148a91af6be791e6d140%2Fimage%20\(2\).png?alt=media)

* The home directory has limited capacity and I/O performance; thus, all computation jobs must be executed in a user’s work space of /scratch, which is the scratch directory.
* A user’s current usage can be checked with the following commands.

```shell-session
$ lfs quota -h /home01
$ lfs quota -h /scratch
```

* A user’s job directory is applied to different policies according to use.
* The file deletion policy(scratch purge policy) is applied based on the access time (atime) of the file attributes.
  * atime(Access timestampe): the last time the file was accessed.
  * mtime(Modified timestampe): the last time the file's content was modified.
  * ctime (Change timestamp): the inode modification time due to changes in file permissions, ownership, links, etc.

<mark style="color:red;">※ In the existing purge policy (files that have not been accessed for 15 days are automatically deleted), recovery of deleted files is basically impossible, but some changes are made to the purge policy to provide a grace period for users who forget to manage files. (2023.05. applied)</mark>

* <mark style="color:red;">After the purge policy is executed, the target file is prefixed with ToBeDelete\_.</mark>\ <mark style="color:red;">e.g.) ToBeDelete\_file1.txt, ToBeDelete\_file2.txt</mark>
  * <mark style="color:red;">If target file is needed, user must directly recover prefixed filename and update atime.</mark>
* <mark style="color:red;">After a certain period of time (20 to 30 days), files marked with ToBeDelete\_ will be deleted in bulk, and the files cannot be recovered.</mark>
* atime can be checked with stat, ls -lu command, etc.

```shell-session
[login01 ~]# stat file1
File: ‘file1’
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: 805h/2053d Inode: 3221237903 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2022-04-05 08:52:30.113048319 +0900
Modify: 2022-04-05 08:52:30.113048319 +0900
Change: 2022-04-05 08:52:30.113048319 +0900
```

```shell-session
$ ls -lu test.file
-rw-r--r-- 1 testuser testgroup 58 Jan 1 17:06  test.file
```

{% hint style="info" %}
Last updated on November 07, 2024.
{% endhint %}
