To install multiple versions for the different instance types, we will use a slurm job.
cat > install-gromacs.sbatch << EOF
#!/bin/bash
#SBATCH --job-name=gromacs-2021.1
#SBATCH --exclusive
#SBATCH --output=%x_%j.out
spack env activate aws
spack env list
spack install --no-check-signature --no-checksum gromacs@2021.1
EOF
sbatch -p c5a ./install-gromacs.sbatch
sbatch -p c5n ./install-gromacs.sbatch