Login Nodes

Login nodes serve as the primary entry point for accessing CRCD systems. They provide secure command-line access over SSH, allowing users to submit jobs, manage files, and launch interactive tasks. Connect to h2p.crc.pitt.edu for the SMP, MPI, and GPU clusters, or htc.crc.pitt.edu for the HTC cluster.

Login nodes are a shared resource that provide fast network access and responsive storage for tasks such as preparing data, compiling code, or submitting jobs.

Don't run heavy work on the login nodes

Login nodes are not intended for large-scale analysis or compute-heavy tasks. Running intensive computations there can slow the system down for all users, and built-in limits on CPU, memory, and runtime may prevent larger jobs from completing. For analysis and compute-heavy work, submit jobs through Slurm to the compute nodes, which are designed for high-performance workloads.

Per-User Resource Limits

To preserve interactivity of the shared login environment, per-user resource limits are enforced via cgroups:

Resource Per-User Limit
CPU cores 1
Memory 8 GB

These limits are collective — they apply to the combined usage of all processes you are running on the login node, regardless of how many there are. When the login node's overall resource pool is exhausted, users may be unable to log in until utilization falls below the threshold.

Processes that exceed these limits or that run compute-intensive workloads may be terminated without notice.

If you need to keep a lightweight process running after disconnecting (e.g., monitoring a job submission or editing files), use tmux or nohup rather than leaving long-running compute work on the login node. For any resource-intensive work, request a dedicated interactive compute node or submit a batch job.

Specifications

Hostname Backend Hostname Architecture Cores/Node Mem/Node Mem/Core OS Drive Network
h2p.crc.pitt.edu login0.crc.pitt.edu Intel Xeon Gold 6326 (Ice Lake) 32 256 GB 8 GB 2x 480 GB NVMe (RAID 1) 25GbE
login1.crc.pitt.edu Intel Xeon Gold 6326 (Ice Lake) 32 256 GB 8 GB 2x 480 GB NVMe (RAID 1) 25GbE
htc.crc.pitt.edu login3.crc.pitt.edu Intel Xeon Gold 6326 (Ice Lake) 32 256 GB 8 GB 2x 480 GB NVMe (RAID 1) 25GbE

  • Connect via SSH

    Reach a login node from a terminal on macOS, Windows, or Linux.

    SSH Using a Terminal

  • Skip the password

    Log in with an SSH key instead of typing your Pitt password each time.

    Passwordless SSH

  • Move work off the login node

    Request a compute node for testing, debugging, and interactive work.

    Interactive Jobs