diff --git a/doc/apptainer/README.md b/doc/apptainer/README.md
index 45b1f2b0..e549614d 100644
--- a/doc/apptainer/README.md
+++ b/doc/apptainer/README.md
@@ -1,6 +1,8 @@
 # Install Fluidsim from source in an Apptainer container
 
-The directory `fluidsim/doc/apptainer` contains what is needed to run Fluidsim with Apptainer.
+The directory `fluidsim/doc/apptainer` contains what is needed to run Fluidsim
+with Apptainer. See also
+https://gricad-doc.univ-grenoble-alpes.fr/hpc/softenv/container/.
 
 ## Build the image locally on a node
 
@@ -15,7 +17,7 @@ apptainer build image-fluidsim.sif image-fluidsim.def
 
 ## Run the image to install Fluidsim from source
 
-From the host:
+From the host (a node of the cluster!):
 
 ```sh
 cd ~/apptainer
@@ -25,5 +27,16 @@ apptainer shell --no-home image-fluidsim.sif
 From the container:
 
 ```sh
-...
+python -m venv venv-fluidsim
+. venv-fluidsim/bin/activate
+HDF5_MPI="ON" pip install --no-binary=h5py h5py pytest pytest-mpi
+python -c 'import h5py; h5py.run_tests()'
+hg clone https://foss.heptapod.net/fluiddyn/fluidsim
+cd fluidsim/
+pip install ".[test,mpi,fft]"
+pytest --pyargs fluidsim
+pip install fluidfft-fftw fluidfft-fftwmpi fluidfft-mpi_with_fftw
+mpirun -np 2 pytest --pyargs fluidsim
+pip install fluidfft-p3dfft
+pip install fluidfft-pfft
 ```
diff --git a/doc/apptainer/image-fluidsim.def b/doc/apptainer/image-fluidsim.def
index d39f211c..1a2e80af 100644
--- a/doc/apptainer/image-fluidsim.def
+++ b/doc/apptainer/image-fluidsim.def
@@ -6,18 +6,37 @@ From: python:3.11
    apt-get -y install mercurial git less meld nano
 
    apt-get install -y --no-install-recommends \
-     libfftw3-dev libfftw3-mpi-dev openmpi-bin libhdf5-openmpi-dev libopenblas-dev
+     libfftw3-dev libfftw3-mpi-dev openmpi-bin libhdf5-openmpi-dev libopenblas-dev \
+     gfortran
 
+   mkdir -p /root/.local/include
+   mkdir -p /root/.local/lib
    export PATH=/root/.local/bin:$PATH
+   export CPATH=/root/.local/include
+   export LIBRARY_PATH=/root/.local/lib
+   export LD_LIBRARY_PATH=/root/.local/lib
+
    python -m pip install pipx
 
    pipx install mercurial
    pipx inject mercurial hg-git hg-evolve hg-fluiddyn
+   wget https://foss.heptapod.net/fluiddyn/fluidsim/-/raw/topic/default/apptainer/doc/apptainer/hgrc -O ~/hgrc
 
    pipx install pdm
    pipx install nox
 
-   wget https://foss.heptapod.net/fluiddyn/fluidsim/-/raw/topic/default/apptainer/doc/apptainer/hgrc -O ~/hgrc
+   ln -s /usr/include/fftw* /root/.local/include
+   ln -s /usr/lib/x86_64-linux-gnu/libfftw3* /root/.local/lib
+
+   wget https://foss.heptapod.net/fluiddyn/fluidfft/raw/branch/default/doc/install/install_p3dfft.sh -O ./install_p3dfft.sh
+   chmod +x install_p3dfft.sh
+   export FCFLAGS="-w -fallow-argument-mismatch -O2"
+   export FFLAGS="-w -fallow-argument-mismatch -O2"
+   ./install_p3dfft.sh
+
+   wget https://foss.heptapod.net/fluiddyn/fluidfft/raw/branch/default/doc/install/install_pfft.sh -O ./install_pfft.sh
+   chmod +x install_pfft.sh
+   ./install_pfft.sh
 
 %startscript
    mkdir -p home
@@ -25,6 +44,9 @@ From: python:3.11
 %environment
    export LC_ALL=C
    export PATH=/root/.local/bin:$PATH
+   export CPATH=/root/.local/include
+   export LIBRARY_PATH=/root/.local/lib
+   export LD_LIBRARY_PATH=/root/.local/lib
    export HOME=$HOME/apptainer/home
    export HGRCPATH=/root/hgrc