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Launching an iDev session with a reservation
As we discussed in our first tutorial the head node is a space shared by all and we don't like stepping on each others toes. While the launcher_creator.py helper script makes working with the compute nodes much easier, they still take time to initiate a run (waiting in the que) and if you have errors in your commands your job will fail and you will lose your place in line. An idev (or interactive development session) is a way to move off the head node and onto a single compute node, but work interactively to see if your commands actually work, give you much quicker feedback, and if everything goes as you hope, your data. idev sessions are much more limited in duration and in general its not necessary to see every line a program spits out once you are familiar with the type of data you will get. Additionally, we are going to use a priority access reservation set up special for the summer school that you normally would not have access to but should guarantee immediate starting of your idev session.
Copy and paste the following command, and read through the commented lines to make sure it is function correctly:
idev -m 180 -r CCBB_Day_1 -A UT-2015-05-18 # This should return the following: # We found an ACTIVE reservation request for you, named CCBB_Day_1. # Do you want to use it for your interactive session? # Enter y/n [default y]: # If for any reason you don't see the above message let me know by raising your hand. # Your answer should be y, which should return the following: # Reservation : --reservation=CCBB_Day_1 (ACTIVE) # Some of you may see a new prompt stating something like the following: # We need a project to charge for interactive use. # We will be using a dummy job submission to determine your project(s). # We will store your (selected) project $HOME/.idevrc file. # Please select the NUMBER of the project you want to charge.\n # 1 OTHER_PROJECTS # 2 UT-2015-05-18 # Please type the NUMBER(default=1) and hit return: # If you see this message, again let me know. # You will then see something similar to the following: # job status: PD # job status: R # --> Job is now running on masternode= nid00032...OK # --> Sleeping for 7 seconds...OK # --> Checking to make sure your job has initialized an env for you....OK # --> Creating interactive terminal session (login) on master node nid00032. # If this takes more than 1 minute get my attention.
Your idev command line contains 3 flags: -m, -r -A. Using the `idev -h` command, can you figure out what these 3 flags mean and what you told the system you wanted to do?