GPUs are a type of resource only available on GPU‑capable nodes (the gpu partition). They are reserved using the --gres parameter. For example, the command below can be used to request an interactive node with 2 cores and access to one of the GPUs available on that node.
srun --partition=gpu --ntasks=1 --nodes=1 --cpus-per-task=2 --gres=gpu:1 --pty /bin/bashNote that if you want a GPU processor, you must explicitly request it with a --gres option. If you request a GPU node without also including a --gres parameter, you’ll be allocated access to only the CPU cores on the GPU node.