Terra Exercises Guide
- 1 Terra Exercises Guide
- 1.1 Terra Usage Policies
- 1.2 Accessing Terra
- 1.3 Terra Exercises: Logging In
- 1.4 The Batch System
- 1.5 Running Your Program / Preparing a Job File
- 1.6 Submitting and Monitoring Jobs
- 1.7 Additional Topics
Terra Usage Policies
Access to Terra is granted with the condition that you will understand and adhere to all TAMU HPRC and Terra-specific policies.
General policies can be found on the HPRC Policies page.
Terra-specific policies, which are similar to Ada, can be found on the Terra Policies page.
Most access to Terra is done via a secure shell session. In addition, two-factor authentication is required to login to any cluster.
Users on Windows computers use either PuTTY or MobaXterm. If MobaXterm works on your computer, it is usually easier to use. When starting an ssh session in PuTTY, choose the connection type 'SSH', select port 22, and then type the hostname 'terra.tamu.edu'. For MobaXterm, select 'Session', 'SSH', and then remote host 'terra.tamu.edu'. Check the box to specify username and type your NetID. After selecting 'Ok', you will be prompted for Duo Two Factor Authentication. For more detailed instructions, visit the Two Factor Authentication page.
Users on Mac and Linux/Unix should use whatever SSH-capable terminal is available on their system. The command to connect to Terra is as follows. Be sure to replace [NetID] with your TAMU NetID.
[user1@localhost ~]$ ssh [NetID]@terra.tamu.edu
Note: In this example [user1@localhost ~]$ represents the command prompt on your local machine.
Your login password is the same that used on Howdy. You will not see your password as your type it into the login prompt.
Off Campus Access
Please visit this page to find information on accessing Terra remotely.
For more detailed instructions on how to access our systems, please see the HPRC Access page.
Terra Exercises: Logging In
When you first access Terra, you will be within your home directory. This directory has smaller storage quotas and should not be used for general purpose. You will also see your current disk and file quota's printed along with the Message of the Day. The Message of the Day includes important policy information and announcements.
You can check your quota with the following command:
[NetID@terra1 ~]$ showquota
You can view the Message of the Day with the following command:
[NetID@terra1 ~]$ motd
You can see your current location in the system with the "print work directory" command:
[NetID@terra1 ~]$ pwd
By default, user's will be placed in their home directory. The home directory has a limit of 10,000 files or 10GB of data. Per our policy, the home directory quota cannot be expanded
[NetID@terra1 ~]$ cd $SCRATCH
Navigate to home with the following command:
[NetID@terra1 ~]$ cd $HOME
Your scratch directory is restricted to 1TB/250,000 files of storage. This storage quota is expandable upon request.
Your home directory is restricted to 10GB/10,000 files of storage. This storage quota is not expandable.
You can see the current status of your storage quotas with:
[NetID@terra1 ~]$ showquota
If you need a storage quota increase, please contact us with justification and the expected length of time that you will need the quota increase.
The Batch System
The batch system is a load distribution implementation that ensures convenient and fair use of a shared resource. Submitting jobs to a batch system allows a user to reserve specific resources with minimal interference to other users. All users are required to submit resource-intensive processing to the compute nodes through the batch system - attempting to circumvent the batch system is not allowed.
On Terra, Slurm is the batch system that provides job management. More information on Slurm can be found in the Terra Batch page.
Running Your Program / Preparing a Job File
In order to properly run a program on Terra, you will need to create a job file and submit a job.
The simple example job file below requests 1 core on 1 node with 2.5GB of RAM for 1.5 hours. Note that typical nodes on Terra have 28 cores with 120GB of usable memory and ensure that your job requirements will fit within these restrictions. Any modules that need to be loaded or executable commands will replace the "#First Executable Line" in this example.
#!/bin/bash ##ENVIRONMENT SETTINGS; CHANGE WITH CAUTION #SBATCH --export=NONE #Do not propagate environment #SBATCH --get-user-env=L #Replicate login environment ##NECESSARY JOB SPECIFICATIONS #SBATCH --job-name=JobExample1 #Set the job name to "JobExample1" #SBATCH --time=01:30:00 #Set the wall clock limit to 1hr and 30min #SBATCH --ntasks=1 #Request 1 task #SBATCH --ntasks-per-node=1 #Request 1 task/core per node #SBATCH --mem=2560M #Request 2560MB (2.5GB) per node #SBATCH --output=Example1Out.%j #Send stdout/err to "Example1Out.[jobID]" #First Executable Line
Note: If your job file has been written on an older Mac or DOS workstation, you will need to use "dos2unix" to remove certain characters that interfere with parsing the script.
[NetID@terra1 ~]$ dos2unix MyJob.slurm
Submitting and Monitoring Jobs
Once you have your job file ready, it is time to submit your job. You can submit your job to slurm with the following command:
[NetID@terra1 ~]$ sbatch MyJob.slurm Submitted batch job 3606
After the job has been submitted, you are able to monitor it with several methods. To see the status of all of your jobs, use the following command:
[NetID@terra1 ~]$ squeue -u NetID JOBID NAME USER PARTITION NODES CPUS STATE TIME TIME_LEFT START_TIME REASON NODELIST 3606 myjob2 NetID short 1 3 RUNNING 0:30 00:10:30 2016-11-27T23:44:12 None tnxt-
To see the status of one job, use the following command, where XXXX is the JobID:
[NetID@terra1 ~]$ squeue --job XXXX JOBID NAME USER PARTITION NODES CPUS STATE TIME TIME_LEFT START_TIME REASON NODELIST XXXX myjob2 NetID short 1 3 RUNNING 0:30 00:10:30 2016-11-27T23:44:12 None tnxt-
To cancel a job, use the following command, where XXXX is the JobID:
[NetID@terra1 ~]$ scancel XXXX
Translating Ada/LSF <--> Terra/Slurm
The HPRC Batch Translation page contains information on converting between LSF, PBS, and Slurm.
Our staff has also written some example jobs for specific software. These software-specific examples can be seen on the Individual Software Pages where available.
Software on Terra is loaded using modules.
You can see the most popular software on the HPRC Available Software page.
You can find most available software on Terra with the following command:
[NetID@terra1 ~]$ module avail
You can search for particular software by keyword using:
[NetID@terra1 ~]$ module spider keyword
You can load a module using:
[NetID@terra1 ~]$ module load moduleName
You can list all currently loaded modules using:
[NetID@terra1 ~]$ module list
You can remove all currently loaded modules using:
[NetID@terra1 ~]$ module purge
If you need new software or an update, please contact us with your request.
There are restrictions on what software we can install. There is also regularly a queue of requested software installations.
Please account for delays in your installation request timeline.
Files can be transferred to Terra using the scp command or a file transfer program.
Our users most commonly utilize:
- WinSCP - Straightforward, legacy
- FileZilla Client - Easy to use, additional features, available on most platforms
- MobaXterm Graphical SFTP - Included with MobaXterm
See our [Terra-Filezilla example video] for a demonstration of this process.
Advice: while GUIs are acceptable for file transfers, the cp and scp commands are much quicker and may significantly benefit your workflow.
Reliably Transferring Large Files
For files larger than several GB, you will want to consider the use of a more fault-tolerant utility such as rsync.
[NetID@terra1 ~]$ rsync -av [-z] localdir/ userid@remotesystem:/path/to/remotedir/
An rsync example can be seen on the Ada Fast Transfer page.
Graphic User Interfaces (Visualization)
The use of GUIs on Terra is a more complicated process than running non-interactive jobs or doing resource-light interactive processing.
You have two options for using GUIs on Terra.
The first option is to run on the login node. When doing this, you must observe the fair-use policy of login node usage. Users commonly violate these policies by accident, resulting in terminated processes, confusion, and warnings from our admins.
The second option is to use a VNC job. This method is outside the scope of this guide. See the Terra Remote Visualization page for more information.