# Example Container (TensorFlow)

There are multiple ways to install and run TensorFlow. Our recommended approach is via NGC containers. The containers are available via [NGC Registry](https://catalog.ngc.nvidia.com/orgs/nvidia/containers/tensorflow). In this example we will pull TensorFlow NGC container

1. Build the container:

   ```bash
   apptainer build tensorflow-24.03-tf2-py3.simg docker://nvcr.io/nvidia/tensorflow:24.03-tf2-py3
   ```

   This process will take some time, and once it completes, you should see a `.simg` file.

   <div data-gb-custom-block data-tag="hint" data-style="danger" class="hint hint-danger"><p>Working with Apptainer images requires a significant amount of storage space. By default, Apptainer will use <code>~/.apptainer</code> as a cache directory, which may exceed your home quota. You can set temporary directories as follows:</p><pre class="language-bash"><code class="lang-bash">export APPTAINER_CACHEDIR=/tmp
   export APPTAINER_TMPDIR=/tmp
   </code></pre></div>
2. Once the container is ready, request an interactive session with a GPU:

   ```bash
   interact -q gpu -g 1 -f ampere -m 20g -n 4
   ```
3. To run a container with GPU support:

   ```bash
   export APPTAINER_BINDPATH="/oscar/home/$USER,/oscar/scratch/$USER,/oscar/data"
   apptainer run --nv tensorflow-24.03-tf2-py3.simg
   ```

   <div data-gb-custom-block data-tag="hint" data-style="success" class="hint hint-success"><p>the --nv flag is important. As it enables the NVIDA sub-system</p></div>
4. Or, if you're executing a specific command inside the container:

   ```bash
   # Execute a command inside the container with GPU support
   apptainer exec --nv tensorflow-24.03-tf2-py3.simg nvidia-smi
   ```
5. Make sure your Tensorflow image is able to detect GPUs

   ```bash
   python
   ```

   ```python
   >>> import tensorflow as tf
   >>> tf.test.is_gpu_available(cuda_only=False, min_cuda_compute_capability=None)
   True
   ```
6. If you need to install additional custom packages, note that the containers themselves are non-writable. However, you can use the `--user` flag to install packages inside `.local`. For example:

   ```console
   Apptainer> pip install <package-name> --user
   ```

## Slurm Script:

Here's how you can submit a SLURM job script using the `srun` command to run your container. Below is a basic example:

```bash
#!/bin/bash
#SBATCH --nodes=1               # node count
#SBATCH -p gpu --gres=gpu:1     # number of gpus per node
#SBATCH --ntasks-per-node=1     # total number of tasks across all nodes
#SBATCH --cpus-per-task=1       # cpu-cores per task (>1 if multi-threaded tasks)
#SBATCH --mem-per-cpu=4G        # total memory per node (4 GB per cpu-core is default)
#SBATCH -t 01:00:00             # total run time limit (HH:MM:SS)
#SBATCH --mail-type=begin       # send email when job begins
#SBATCH --mail-type=end         # send email when job ends
#SBATCH --mail-user=<USERID>@brown.edu

module purge
unset LD_LIBRARY_PATH
srun apptainer exec --nv tensorflow-24.03-tf2-py3.simg python examples/tensorflow_examples/models/dcgan/dcgan.py
```