From 49904470bab33cfe57cdee9f8740650d8765c5ef Mon Sep 17 00:00:00 2001 From: Shuhei Matsumoto Date: Thu, 23 Jul 2020 12:29:24 +0900 Subject: [PATCH] doc/iscsi: Add description about iSCSI login redirection Signed-off-by: Shuhei Matsumoto Change-Id: Idac2940bac28b3513bb38c4fd6768fdb38f7a715 Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/3494 Community-CI: Mellanox Build Bot Tested-by: SPDK CI Jenkins Reviewed-by: Jim Harris Reviewed-by: Changpeng Liu --- doc/iscsi.md | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/doc/iscsi.md b/doc/iscsi.md index b1eaa1711..ed1e30ff3 100644 --- a/doc/iscsi.md +++ b/doc/iscsi.md @@ -325,3 +325,37 @@ At the iSCSI level, we provide the following support for Hotplug: return back; after all the commands return back, the LUN will be deleted. @sa spdk_nvme_probe + +# iSCSI Login Redirection {#iscsi_login_redirection} + +The SPDK iSCSI target application supports iSCSI login redirection feature. + +A portal refers to an IP address and TCP port number pair, and a portal group +contains a set of portals. Users for the SPDK iSCSI target application configure +portals through portal groups. + +To support login redirection feature, we utilize two types of portal groups, +public portal group and private portal group. + +The SPDK iSCSI target application usually has a discovery portal. The discovery +portal is connected by an initiator to get a list of targets, as well as the list +of portals on which these target may be accessed, by a discovery session. + +Public portal groups have their portals returned by a discovery session. Private +portal groups do not have their portals returned by a discovery session. A public +portal group may optionally have a redirect portal for non-discovery logins for +each associated target. This redirect portal must be from a private portal group. + +Initiators configure portals in public portal groups as target portals. When an +initator logs in to a target through a portal in an associated public portal group, +the target sends a temporary redirection response with a redirect portal. Then the +initiator logs in to the target again through the redirect portal. + +Users set a portal group to public or private at creation using the +`iscsi_create_portal_group` RPC, associate portal groups with a target using the +`iscsi_create_target_node` RPC or the `iscsi_target_node_add_pg_ig_maps` RPC, and +specify a up-to-date redirect portal in a public portal group for a target using +`iscsi_target_node_set_redirect` RPC. + +Typically users will use the login redirection feature in scale out iSCSI target +system, which runs multiple SPDK iSCSI target applications.