doc/cephadm: docs for extra entrypoint args

Signed-off-by: Adam King <adking@redhat.com>
(cherry picked from commit 8ee799e9cc0800fbedc8d9343aa3207bc9fd429e)

Conflicts:
	doc/cephadm/services/index.rst

diff --git a/doc/cephadm/services/index.rst b/doc/cephadm/services/index.rst
index 26fd8864a808b62b48af52a7f7e320efb3f38ab2..317fc4c69dd3a3b27584e0866582317d4ac0e80e 100644 (file)
--- a/doc/cephadm/services/index.rst
+++ b/doc/cephadm/services/index.rst
@@ -496,11 +496,20 @@ candidate hosts.
    If there are fewer hosts selected by the placement specification than
    demanded by ``count``, cephadm will deploy only on the selected hosts.
 
+.. _cephadm-extra-container-args:
+
 Extra Container Arguments
 =========================
 
 .. warning:: 
-  The arguments provided for extra container args are limited to whatever arguments are available for a `run` command from whichever container engine you are using. Providing any arguments the `run` command does not support (or invalid values for arguments) will cause the daemon to fail to start.
+  The arguments provided for extra container args are limited to whatever arguments are available for
+  a `run` command from whichever container engine you are using. Providing any arguments the `run`
+  command does not support (or invalid values for arguments) will cause the daemon to fail to start.
+
+.. note::
+
+  For arguments passed to the process running inside the container rather than the for
+  the container runtime itself, see :ref:`cephadm-extra-entrypoint-args`
 
 
 Cephadm supports providing extra miscellaneous container arguments for
@@ -544,6 +553,30 @@ For example:
       - "-v"
       - "/opt/ceph_cert/host.cert:/etc/grafana/certs/cert_file:ro"
 
+.. _cephadm-extra-entrypoint-args:
+
+Extra Entrypoint Arguments
+==========================
+
+.. note::
+
+  For arguments intended for the container runtime rather than the process inside
+  it, see :ref:`cephadm-extra-container-args`
+
+Similar to extra container args for the container runtime, Cephadm supports
+appending to args passed to the entrypoint process running
+within a container. For example, to set the collector textfile directory for
+the node-exporter service , one could apply a service spec like
+
+.. code-block:: yaml
+
+  service_type: node-exporter
+  service_name: node-exporter
+  placement:
+    host_pattern: '*'
+  extra_entrypoint_args:
+    - "--collector.textfile.directory=/var/lib/node_exporter/textfile_collector2"
+
 .. _orch-rm:
 
 Removing a Service