Scheduler and allocation
allocation : Compute resources (cores, memory, GPUs, wall time) that a scheduler grants temporarily to a job.
batch scheduler : Software, such as Slurm or a PBS-family system, that assigns shared cluster resources and controls when jobs run.
job : Submitted work that requests resources and runs inside an allocation until completion, cancellation, failure, or timeout.
job step : A process the scheduler launches and tracks within an allocation; one job can contain several steps.
orchestration boundary : The system responsible for starting and connecting processes. Compose fills this role on a laptop; on HPC, the scheduler allocation and launch script fill it together.
reclamation : The scheduler returning allocated resources to the cluster when a job ends or reaches its wall-time limit.
terminal state
: The scheduler’s final classification of a job, such as COMPLETED, FAILED, TIMEOUT, or CANCELLED.
wall time : The maximum duration requested for a job. The scheduler ends a job that reaches this limit.
Runtime and storage
bind : A host filesystem path mounted at a chosen path inside a container.
immutable image
: A read-only container image, such as an Apptainer .sif file, replaced through a verified rebuild rather than edited during a run.
job-scoped scratch : Temporary writable storage assigned to one job and unsuitable for durable results.
module load : A command that makes center-managed software available in the current environment.
rootless runtime : A container runtime, such as Apptainer or Charliecloud, that launches containers without a privileged daemon or root access.
Workflow mechanics
checksum (SHA-256) : A content fingerprint used to verify that a file matches an expected artifact.
inert input : Input parsed as data rather than evaluated as code or shell commands.
loopback
: The local-only network interface, usually 127.0.0.1, used to keep a service reachable only from the same machine.
readiness check : A test that confirms a service can perform its required operation before dependent work starts.
semantic readiness : A readiness check that verifies a correct service response rather than only an open port.
SSH tunnel : An encrypted forwarding path used to reach a remote service through SSH without publishing its port broadly.
success marker : A machine-readable file written only after the workflow’s documented result checks pass.
Continue with Scheduler as Orchestrator, the Baseline Pattern, or Getting started.