From a33f455ec74f7087bf28cc74512e0608a166a9ea Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ji=C5=99=C3=AD=20Suchomel?= Date: Fri, 15 May 2020 12:20:03 +0200 Subject: [PATCH] Adapt the admin guide to describe the direct RBD export This documents how to set up nova and glance so the feature for direct download from Ceph can be used. Change-Id: I07509c67c65e988fe5149b625007e90e68488cfd --- .../admin/configuration/hypervisor-kvm.rst | 30 +++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/doc/source/admin/configuration/hypervisor-kvm.rst b/doc/source/admin/configuration/hypervisor-kvm.rst index 243e7eb238..31a9731b15 100644 --- a/doc/source/admin/configuration/hypervisor-kvm.rst +++ b/doc/source/admin/configuration/hypervisor-kvm.rst @@ -260,6 +260,36 @@ Local `LVM volumes used. Set the :oslo.config:option:`libvirt.images_volume_group` configuration option to the name of the LVM group you have created. +Direct download of images from Ceph +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +When the Glance image service is set up with the Ceph backend and Nova is using +a local ephemeral store (``[libvirt]/images_type!=rbd``), it is possible to +configure Nova to download images directly into the local compute image cache. + +With the following configuration, images are downloaded using the RBD export +command instead of using the Glance HTTP API. In some situations, especially +for very large images, this could be substantially faster and can improve the +boot times of instances. + +On the Glance API node in ``glance-api.conf``: + +.. code-block:: ini + + [DEFAULT] + show_image_direct_url=true + +On the Nova compute node in nova.conf: + +.. code-block:: ini + + [glance] + enable_rbd_download=true + rbd_user=glance + rbd_pool=images + rbd_ceph_conf=/etc/ceph/ceph.conf + rbd_connect_timeout=5 + Specify the CPU model of KVM guests ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~