diff --git a/index.md b/index.md
index db5778d..1d547b7 100644
--- a/index.md
+++ b/index.md
@@ -10,6 +10,7 @@ Setup [Drone CI autoscaler](https://autoscale.drone.io/).
 * [Default Variables](#default-variables)
   * [droneci_autoscaler_agent_architecture](#droneci_autoscaler_agent_architecture)
   * [droneci_autoscaler_agent_concurrency](#droneci_autoscaler_agent_concurrency)
+  * [droneci_autoscaler_agent_distro](#droneci_autoscaler_agent_distro)
   * [droneci_autoscaler_agent_image](#droneci_autoscaler_agent_image)
   * [droneci_autoscaler_agent_os](#droneci_autoscaler_agent_os)
   * [droneci_autoscaler_agent_package_upgrade](#droneci_autoscaler_agent_package_upgrade)
@@ -69,6 +70,14 @@ droneci_autoscaler_agent_architecture: amd64
 droneci_autoscaler_agent_concurrency: 2
 ```
 
+### droneci_autoscaler_agent_distro
+
+#### Default value
+
+```YAML
+droneci_autoscaler_agent_distro: ubuntu
+```
+
 ### droneci_autoscaler_agent_image
 
 #### Default value