From 2e1d31a44aee148fbfbcf14ccb8994a85ac3a952 Mon Sep 17 00:00:00 2001 From: Matt Riedemann Date: Thu, 25 Jan 2018 13:48:05 -0500 Subject: [PATCH] api-ref: add multiattach considerations to retype docs This adds some notes about two things to consider with a volume retype operation on an in-use multiattach volume: 1. The volume API will reject a retype operation on an in-use volume where the volume's multiattach value would change. 2. Retyping an in-use volume that has more than one active read/write attachment is not recommended because on the nova side the swap volume operation performs a blockRebase which could potentially lead to data corruption. In the future, we (nova or cinder or both) will likely need to make some changes as to what the default attach_mode is for secondary attachments to a multiattach volume, since today we default to read/write if it's not specified by the caller when making the attachment. Change-Id: Ib5a2830ea3cd37236947677225252ef42edaa347 --- api-ref/source/v2/volumes-v2-volumes-actions.inc | 5 +++++ api-ref/source/v3/volumes-v3-volumes-actions.inc | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/api-ref/source/v2/volumes-v2-volumes-actions.inc b/api-ref/source/v2/volumes-v2-volumes-actions.inc index 6a3bf043d67..43121dbb23a 100644 --- a/api-ref/source/v2/volumes-v2-volumes-actions.inc +++ b/api-ref/source/v2/volumes-v2-volumes-actions.inc @@ -340,6 +340,11 @@ Change type of existing volume. Specify the ``os-retype`` action in the request Change the volume type of existing volume, Cinder may migrate the volume to proper volume host according to the new volume type. +Retyping an *in-use* volume from a multiattach-capable type to a +non-multiattach-capable type, or vice-versa, is not supported. It is generally +not recommended to retype an *in-use* multiattach volume if that volume has +more than one active read/write attachment. + Policy defaults enable only users with the administrative role or the owner of the volume to perform this operation. Cloud providers can change these permissions through the policy.json file. diff --git a/api-ref/source/v3/volumes-v3-volumes-actions.inc b/api-ref/source/v3/volumes-v3-volumes-actions.inc index 407c57b0a52..7cdd22cf544 100644 --- a/api-ref/source/v3/volumes-v3-volumes-actions.inc +++ b/api-ref/source/v3/volumes-v3-volumes-actions.inc @@ -369,6 +369,11 @@ Change type of existing volume. Specify the ``os-retype`` action in the request Change the volume type of existing volume, Cinder may migrate the volume to proper volume host according to the new volume type. +Retyping an *in-use* volume from a multiattach-capable type to a +non-multiattach-capable type, or vice-versa, is not supported. It is generally +not recommended to retype an *in-use* multiattach volume if that volume has +more than one active read/write attachment. + Policy defaults enable only users with the administrative role or the owner of the volume to perform this operation. Cloud providers can change these permissions through the policy.json file.