diff --git a/README.md b/README.md
index 83aad91..86eed0f 100644
--- a/README.md
+++ b/README.md
@@ -108,3 +108,7 @@ Host deuxfleurs
 Now, to connect, do the following:
 
     ssh deuxfleurs -N 
+
+## Test cluster
+
+Configured machines available for testing are listed in the **[`test_cluster` Ansible inventory](./os/config/test_cluster.inventory.yml)**.
\ No newline at end of file
diff --git a/os/config/roles/common/tasks/main.yml b/os/config/roles/common/tasks/main.yml
index 1039b1e..7b96d28 100644
--- a/os/config/roles/common/tasks/main.yml
+++ b/os/config/roles/common/tasks/main.yml
@@ -28,14 +28,14 @@
       - bmon
       - iftop
       - iotop
-      - docker.io
+      # - docker.io # The bad way of installing Docker
       - locales
       - unzip
       - tar
       - tcpdump
       - less
       - parted
-      - btrfs-tools
+      # - btrfs-tools # not in Debian 11
       - libnss-resolve
       - net-tools
       - strace
diff --git a/os/config/test_cluster.inventory.yml b/os/config/test_cluster.inventory.yml
new file mode 100644
index 0000000..24af6c1
--- /dev/null
+++ b/os/config/test_cluster.inventory.yml
@@ -0,0 +1,13 @@
+cluster_nodes:
+  hosts:
+    spoutnik:
+      ansible_host: spoutnik.machine.deuxfleurs.fr
+      ansible_port: 220
+      ansible_become: true
+      ipv4: 192.168.0.40
+      gatewayv4: 192.168.0.1
+      interface: enp0s25
+      dns_1: 192.168.0.50
+      dns_2: 212.27.40.241
+      ansible_python_interpreter: python3
+      contact_name: ADRN
\ No newline at end of file