CentOS 7 Upgrade: login.accre.vanderbilt.edu now points to CentOS 7, login6.accre.vanderbilt.edu available temporarily for GPU users
Update, 9/28/2018: We have now pointed
login.accre.vanderbilt.edu to the CentOS 7 environment.
Update, 9/27/2018: Tomorrow afternoon we will be pointing
login.accre.vanderbilt.edu at the CentOS 7 environment. Due to DNS caching this change may not take effect until Saturday or later on your local machine. After the switchover, if you are asked to verify that you trust the authenticity of the remote host when you attempt to ssh to
login.accre.vanderbilt.edu, please respond “yes”. A small set of users may also get warnings about spoofing. If you see this warning, please remove
login.accre.vanderbilt.edu from your
~/.ssh/known_hosts file and try logging in again. If you would like to access the CentOS 6 environment after the switchover, you will need to use
login-old.accre.vanderbilt.edu as indicated below). At this point, we also encourage all custom gateway owners to schedule a time to upgrade their gateways to CentOS 7. Please open a helpdesk ticket with us to discuss if you have not done so already. Please read previous email messages below for more details about the CentOS 7 upgrade.
Update, 9/24/2018: A reminder that on Friday at around 3pm, we will be switching over login.accre.vanderbilt.edu to the CentOS 7 environment as described below. You can access this environment now by connecting to login7.accre.vanderbilt.edu.
We ask our GPU users to continue to use CentOS 6, which will be available following the switchover at login-old.accre.vanderbilt.edu. We are working with Mellanox support to overcome a bug in their driver for the network cards in the GPU nodes.
Update, 9/5/2018: Getting Ready for the CentOS 7 Upgrade
Update, 8/13/2018: This is a friendly reminder to please test your workflows in the CentOS 7 environment as soon as possible.
See our website for regular updates on the number of cores on the CentOS 6 side versus CentOS 7 side. We will be deploying a large number of new Intel Xeon Skylake-based processors in the next few weeks in the CentOS 7 environment, at which point the number of compute resources on the CentOS 7 side will exceed those available in the old environment.
Below are some points of confusion that have come up in tickets related to the CentOS 7 transition:
- We currently have two independent instances of SLURM running that are each managing a separate set of compute nodes. If you submit a job from a CentOS 7 gateway (login7.accre.vanderbilt.eduor a custom gateway that has been upgraded to CentOS 7), your job will run on a CentOS 7 compute node. If you submit a job from a CentOS 6 gateway (login.accre.vanderbilt.edu or a custom gateway that has not been upgrade to CentOS 7) then your job will run on a CentOS 6 compute nodes. You should notice that the instance of SLURM managing CentOS 7 resources is significantly more responsive than the one managing CentOS 6 compute nodes.
- There may be some slight changes in the names of LMod packages between CentOS 6 and 7, so please make use of the “ml spider” subcommand to search for the appropriate names and versions of a particular package you used in the CentOS 6 environment. Please also use this opportunity to research collections in LMod as these will help prevent common problems we see frequently in helpdesk tickets. Note that module collections created in the CentOS 6 environment must be deleted and re-created in the CentOS 7 environment.
- We currently have separate authentication systems running in parallel – one is managing passwords in the CentOS 6 environment and one is managing passwords in the CentOS 7 environment. We are synchronizing passwords from CentOS 6 to CentOS 7, but not vice versa, and the process for changing your password has changed in CentOS 7. Please see: Password Change Information
ACCRE has begun transitioning its cluster operating system from CentOS 6 to 7, along with many new features and improvements (including improved SLURM responsiveness) that are detailed here.