From e79f163837dd2c27f84f693aba0f1575fa2353f7 Mon Sep 17 00:00:00 2001
From: Dmitry Tantsur <dtantsur@protonmail.com>
Date: Mon, 3 May 2021 17:35:26 +0200
Subject: [PATCH] Update refarch with information about image_download_source
Change-Id: Ia06b01e89d79bf0f65d95dd0c20e91b456b8acae
---
doc/source/admin/interfaces/deploy.rst | 2 ++
doc/source/install/refarch/common.rst | 25 ++++++++++++++++++-------
2 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/doc/source/admin/interfaces/deploy.rst b/doc/source/admin/interfaces/deploy.rst
index f8fbb39163..aaac9245ea 100644
--- a/doc/source/admin/interfaces/deploy.rst
+++ b/doc/source/admin/interfaces/deploy.rst
@@ -27,6 +27,8 @@ You can specify this deploy interface when creating or updating a node::
``agent``. This is because before the Kilo release **ironic-python-agent**
used to only support this deploy interface.
+.. _image_download_source:
+
Deploy with custom HTTP servers
-------------------------------
diff --git a/doc/source/install/refarch/common.rst b/doc/source/install/refarch/common.rst
index 0c1e998030..f4fdac2b81 100644
--- a/doc/source/install/refarch/common.rst
+++ b/doc/source/install/refarch/common.rst
@@ -312,15 +312,26 @@ the space requirements are different:
* The deployment kernel and ramdisk are always cached during the deployment.
-* The ``iscsi`` deploy method requires caching of the whole instance image
- locally during the deployment. The image has to be converted to the raw
- format, which may increase the required amount of disk space, as well as
- the CPU load.
+* When ``[agent]image_download_source`` is set to ``http`` and Glance is used,
+ the conductor will download instances images locally to serve them from its
+ HTTP server. Use ``swift`` to publish images using temporary URLs and convert
+ them on the node's side.
+
+ When ``[agent]image_download_source`` is set to ``local``, it will happen
+ even for HTTP(s) URLs. For standalone case use ``http`` to avoid unnecessary
+ caching of images.
+
+ In both cases a cached image is converted to raw if ``force_raw_images``
+ is ``True`` (the default).
.. note::
- This is not a concern for the ``direct`` deploy interface, as in this case
- the deployment ramdisk downloads the image and either streams it to the
- disk or caches it in memory.
+ ``image_download_source`` can also be provided in the node's
+ ``driver_info`` or ``instance_info``. See :ref:`image_download_source`.
+
+* The ``iscsi`` deploy method always requires caching of the whole instance
+ image locally during the deployment. The image has to be converted to the raw
+ format, which may increase the required amount of disk space, as well as the
+ CPU load.
* When network boot is used, the instance image kernel and ramdisk are cached
locally while the instance is active.