A minimal example of shared allocation between CI jobs on Gitlab (using Slurm)

.gitlab-ci.yml

##############################################################################
# Copyright (c) 2022, Lawrence Livermore National Security, LLC and RADIUSS
# project contributors. See the COPYRIGHT file for details.
#
# SPDX-License-Identifier: (MIT)
##############################################################################

# The allocation name must be unique
variables:
  ALLOC_NAME: ${CI_PROJECT_NAME}_ci_${CI_PIPELINE_ID}

stages:
  - allocate
  - run
  - release

.on_ruby:
  tags:
    - shell
    - ruby

allocate_resources (on ruby):
  extends: .on_ruby
  variables:
    GIT_STRATEGY: none
  stage: allocate
  script:
    - salloc --partition=pdebug --time=10 --nodes=1 --cpus-per-task=36 --no-shell --job-name=${ALLOC_NAME}

run:1:
  extends: .on_ruby
  # With slum versions >= 20.11 it is mandatory to specify whether we want concurrent/overlapping jobs
  variables:
    SLURM_OVERLAP: 1
  stage: run
  script:
    # Retrieving the allocation name in a separate shell is the uglier part
    - export JOBID=$(squeue -h --name=${ALLOC_NAME} --format=%A)
    # Allocation options here serve for scheduling inside the main allocation
    - srun $( [[ -n "${JOBID}" ]] && echo "--jobid=${JOBID}" ) --time=1 --nodes=1 ./script

run:2:
  extends: .on_ruby
  variables:
    SLURM_OVERLAP: 1
  stage: run
  script:
    - export JOBID=$(squeue -h --name=${ALLOC_NAME} --format=%A)
    - srun $( [[ -n "${JOBID}" ]] && echo "--jobid=${JOBID}" ) --time=1 --nodes=1 ./script

run:3:
  extends: .on_ruby
  variables:
    SLURM_OVERLAP: 1
  stage: run
  script:
    - export JOBID=$(squeue -h --name=${ALLOC_NAME} --format=%A)
    - srun $( [[ -n "${JOBID}" ]] && echo "--jobid=${JOBID}" ) --time=1 --nodes=1 ./script

release_resources (on ruby):
  variables:
    GIT_STRATEGY: none
  extends: .on_ruby
  stage: release
  script:
    - export JOBID=$(squeue -h --name=${ALLOC_NAME} --format=%A)
    - ([[ -n "${JOBID}" ]] && scancel ${JOBID})
  # Releasing the allocation must be done even of pipeline failure.
  when: always


#### script example for demo: ####
#
# #!/bin/bash
#
# echo "## START: $(date)"
# echo "This script is running on $(hostname)"
# echo "Let’s sleep for 3 seconds..."
# sleep 3
# echo "## END: $(date)"