Interactive Sessions

Interactive sessions give you a terminal attached to allocated compute nodes — similar to salloc + srun --pty in Slurm.

Creating a Session

# Basic interactive session (1 node, 4 hours)
lattice session --walltime=4h

# With GPU and software environment
lattice session --nodes=1 --constraint="gpu_type=GH200" --uenv=prgenv-gnu/24.11:v1

# Specify vCluster
lattice session --vcluster=interactive --walltime=2h

The session enters the queue like any other allocation. Once scheduled, your terminal automatically attaches to the first node.

Attaching to Running Allocations

You can attach a terminal to any running allocation (not just sessions):

# Attach to a running job
lattice attach a1b2c3d4

# Attach to a specific node in a multi-node allocation
lattice attach a1b2c3d4 --node=nid001234

# Run a specific command instead of a shell
lattice attach a1b2c3d4 -- htop

Multiple Terminals

You can open multiple terminals to the same allocation:

# Terminal 1
lattice attach a1b2c3d4

# Terminal 2 (different shell window)
lattice attach a1b2c3d4

Session Lifecycle

• Pending — waiting in the queue for resources
• Running — terminal is attached, you’re working
• Disconnected — if you lose connection, the session keeps running (use tmux/screen inside for persistence)
• Completed — walltime expired or you exited

Tips

• Use tmux or screen inside your session for disconnect resilience
• Sessions respect the same preemption rules as batch jobs — use --preemption-class=7 for important interactive work
• If preempted, you’ll see checkpoint progress in your terminal before disconnection
• The --walltime flag is mandatory for sessions (prevents runaway resource usage)