Added idle culler docs

docs/index.rst

@@ -123,6 +123,7 @@ Topic guides provide in-depth explanations of specific topics.
    topic/tljh-config
    topic/authenticator-configuration
    topic/escape-hatch
+   topic/idle-culler
 
 
 Troubleshooting

docs/topic/idle-culler.rst

@@ -0,0 +1,86 @@
+.. _topic/idle-culler:
+
+=============================
+Culling idle notebook servers
+=============================
+
+The idle culler is a hub-managed service that automatically shuts down idle
+single-user notebook servers in order to free up resources. After culling, any
+in-memory data will be lost.
+
+
+Disabling the idle culler
+=========================
+
+The idle culling service is enabled by default. To disable it, use the following
+command:
+
+.. code-block:: bash
+
+   sudo tljh-config set services.cull.enabled False
+
+
+Configuring the idle culler
+===========================
+
+By **default**,  JupyterHub will:
+	* Run the culling process every minute.
+	* Cull any user servers that have been inactive for more than 10 minutes.
+
+The configuration options available are:
+
+Idle timeout
+------------
+
+The idle timeout (in seconds) can be configured using:
+
+.. code-block:: bash
+
+	sudo tljh-config set services.cull.timeout <max-idle-sec-before-server-is-culled>
+
+*By default services.cull.timeout = 600*
+
+Idle check interval
+-------------------
+
+The interval (in seconds) for checking for idle servers to cull can be configured using:
+
+.. code-block:: bash
+
+ 	sudo tljh-config set services.cull.every <number-of-sec-this-check-is-done>
+
+*By default services.cull.every = 60*
+
+Maximum age
+-----------
+
+The maximum age (in seconds) of servers that should be culled even if they are active
+can be configured using:
+
+.. code-block:: bash
+
+ 	sudo tljh-config set services.cull.max_age <server-max-age>
+
+*By default services.cull.max_age = 0*
+
+User culling
+------------
+
+In addition to servers, the users will also be culled if the following command is used:
+
+.. code-block:: bash
+
+ 	sudo tljh-config set services.cull.users True
+
+*By default services.cull.users = False*
+
+Concurrency
+-----------
+
+The number of concurrent requests made to the Hub ca be configured using:
+
+.. code-block:: bash
+
+ 	sudo tljh-config set services.cull.concurrency <number-of-concurrent-hub-requests>
+
+*By default services.cull.concurrency = 5*