What is Armis2?
Armis2 is an ARC-managed HPC cluster available for researchers who work with Protected Health Information (HIPAA). All computational work is scheduled via the Slurm resource manager and task scheduler, while data is kept on Turbo Research Storage. To request an allocation please contact arcts-support@umich.edu.
Who can use Armis2?
Armis2 is available for researchers at the University of Michigan who require HIPAA-compliant high performance computing. If you do not work with HIPAA data, your needs may be met by other ARC services (i.e., Great Lakes or Lighthouse).
What forms do I need to fill out?
- The Principal Investigator (PI) needs to email arcts-support@umich.edu for an account, specifying users that can access the account and payment details.
- Each user given access to the account must request a user login. Please refer to the Armis2 User Guide for additional steps and usage information.
What is a UMRCP account and how can I get one on Armis2?
The University of Michigan Research Computing Package (UMRCP), provided by ITS, is an investment into the U-M research community via simple, dependable access to several ITS-provided high-performance computing clusters and data storage resources. For more information, please visit our UMRCP page.
How much does Armis2 cost?
Currently, there is no charge for using Armis2. Armis2 has an on-demand job model, paying for the resources your job uses, and there will be a rate applied on January 6th, 2020. For current prices, see the HPC rates page.
As a PI, how can I limit usage on my account?
Principal Investigators can request that CPU, GPU, memory, billing units, and walltime be limited per user or group of users on their account. For more information, see the Armis2 policy documentation.
Limits must be requested by emailing arcts-support@umich.edu.
What should I do if I receive a Bad Request error when accessing Open OnDemand?
If you receive a “Bad Request: Your browser sent a request that this server could not understand. Size of request header field exceeds server limit.” error, please clear your browser’s cookies and try to access Armis2 OnDemand again.
This error can occur when the request header sent by the browser becomes too large. This is typically caused by accumulated cookies and cached data for a specific site; in some cases, corrupted cookies can also contribute to the problem.
The vendor of Open OnDemand stated that, currently, it does not do cookie/cache clean-up. We recommend using your browser in incognito mode to avoid this potential issue.
What is the difference between GiB vs GB, MiB vs MB?
A gibibyte (GiB) and a gigabyte (GB) are sometimes used as synonyms, though technically they do not describe the same amount of data capacity. What’s the difference? A gibibyte is a unit of measurement for data capacity in computing, and is based on powers of two. A gigabyte is also a unit of measurement for data, but is based in powers of 10. For example, 1 GiB equals 1,024 MiBs and 1 GB equals 1000 MiBs. This concept can be applied to the other prefixes. With the expansion of data capacity, gigabytes have become a more outdated unit of measure when compared to gibibytes. To be as accurate and consistent as possible, Slurm, slurm mail, and our additional tooling uses binary byte notation (GiB, MiB, etc) to measure data capacity.
Can I use SSH key-based authentication to access Armis2?
Unfortunately, this is not currently possible. We use Kerberos, a network authentication protocol which utilizes a different system based on tickets and symmetric-key cryptography. This system isn’t compatible with the public-private key pair used in SSH key-based authentication.
While we understand the convenience of SSH keys, it’s crucial that we prioritize our system’s security, which Kerberos affords us through centralized and time-sensitive ticketing control.
What are the SSH pub keys for Armis 2?
If you wish to pre-populate your SSH client configuration with the publicly available keys for Armis 2, they are as follows:
ECDSA:
armis2.arc-ts.umich.edu,armis2-login?.arc-ts.umich.edu,141.211.19.10,141.211.19.11 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBHWel/rAXqIJYxexVzMSlgy/fICWukn8DaOGMPpAomH1E5AhCjrH2zMMTJHtXYsRA+brm/sTbn21Zw+pgpgJSYA=
ED25519:
armis2.arc-ts.umich.edu,armis2-login?.arc-ts.umich.edu,141.211.19.10,141.211.19.11 ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAICwaAq9LI48vVO4qbt35Xfz1pi+RE1Krq1iIeJQqoFEw
RSA:
armis2.arc-ts.umich.edu,armis2-login?.arc-ts.umich.edu,141.211.19.10,141.211.19.11 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEA16eDiBWF3SgPQXEeJsH8dsxO8x3o5KkdqWMg/lK57Kpwf4QGXJNvYy0jxSAuKTRim/ob6+nDRH8zIOwnl9tlyEw+8VN3WR8nqBqxX6Km2yzTOMO8Lh7fLuMTZHOdEz0uOn6tBP8LTMtHN9h/fANjKFVl8N+jsejMXrPf0w7jGjc=
On a Mac or Linux machine you’ll add the keys to your known_hosts file.
On a Mac this file is: /Users/<username>/.ssh/known_hosts.
On Linux: /home/<username>/.ssh/known_hosts.
The known_hosts file should have 644 (i.e. -rw-r--r--) permissions.
If you are using an SSH client that is not part of your operating system (e.g. Windows using PuTTY), please see the client documentation referring to host key verification.
A good start for PuTTY users can be found here (section A.2.9 “Is there an option to turn off the annoying host key prompts?)”
Can I get a refund on a failed job?
Any refunds (if any) are at the discretion of ARC and will only only be enacted during system-wide preventable issues. This does not include hardware failure, power failures, job failures, or similar issues. For more information, see the Armis2 policies.
If you have questions, please send email to arcts-support@umich.edu.
