diff --git a/index.md b/index.md
index 6260c1d..1eba726 100644
--- a/index.md
+++ b/index.md
@@ -19,6 +19,7 @@ Setup [certbot](https://certbot.eff.org/) Let's Encrypt client.
   * [certbot_domain_groups](#certbot_domain_groups)
   * [certbot_email](#certbot_email)
   * [certbot_log_dir](#certbot_log_dir)
+  * [certbot_max_log_backups](#certbot_max_log_backups)
   * [certbot_packages_extra](#certbot_packages_extra)
   * [certbot_preferred_challenges](#certbot_preferred_challenges)
   * [certbot_rsa_key_size](#certbot_rsa_key_size)
@@ -134,6 +135,14 @@ certbot_email: mail@example.com
 certbot_log_dir: /var/log/letsencrypt
 ```
 
+### certbot_max_log_backups
+
+#### Default value
+
+```YAML
+certbot_max_log_backups: 30
+```
+
 ### certbot_packages_extra
 
 Extra packages to install with pip (e.g. DNS plugins).