Bug 1593459 – RFE: Make multipath able to blacklist by protocol/transport

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Bug 1593459 - RFE: Make multipath able to blacklist by protocol/transport

Summary:	RFE: Make multipath able to blacklist by protocol/transport

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	device-mapper-multipath (Show other bugs)
Sub Component:
Version:	7.6
Hardware:	Unspecified Unspecified

Priority	high Severity unspecified
Target Milestone:	rc
Target Release:	---
Assigned To:	Ben Marzinski
QA Contact:	Lin Li
Docs Contact:	Marek Suchanek

URL:
Whiteboard:
Keywords:	FutureFeature, ZStream

Duplicates:	1600672 (view as bug list)
Depends On:
Blocks:	1016535 1600672 1607749
	Show dependency tree / graph

Reported:	2018-06-20 18:00 EDT by Ben Marzinski
Modified:	2018-10-30 07:28 EDT (History)
CC List:	10 users (show)

See Also:
Fixed In Version:	device-mapper-multipath-0.4.9-121.el7
Doc Type:	Release Note
Doc Text:	DM Multipath now enables blacklisting or whitelisting paths by protocol Device Mapper Multipath (DM Multipath) now supports the "protocol" configuration option in the `blacklist` and `blacklist_exceptions` configuration sections. This enables you to blacklist or whitelist paths based on the protocol they use, such as `scsi` or `nvme`. For SCSI devices, you can also specify the transport: for example `scsi:fcp` or `scsi:iscsi`.
Story Points:	---
Clone Of:
Clones:	1607749 (view as bug list)
Environment:
Last Closed:	2018-10-30 07:27:36 EDT
Type:	Bug
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHBA-2018:3236	None	None	None	2018-10-30 07:28 EDT

Groups: None (edit)

Description Ben Marzinski 2018-06-20 18:00:43 EDT

Description of problem:
Right now, there is no way to easily tell multipath that you want to blacklist or whitelist devices based on what protocol and transport method that they are using. You can't easily (for instance) blacklist all devices except scsi devices using Fibre Channel or iSCSI. To solve this multipath needs a new blacklist/blacklist_exceptions type, "protocol". This will allow you to do things like

blacklist {
        protocol ".*"
}

blacklist_exceptions {
        protocol "(scsi:fcp|scsi:iscsi)"
}

Comment 2 Nir Soffer 2018-06-20 18:30:11 EDT

(In reply to Ben Marzinski from comment #0)
> blacklist_exceptions {
>         protocol "(scsi:fcp|scsi:iscsi)"
> }

Ben, can you explain why "scsi:fcp" or "scsi:iscsi" is needed, instead of "fcp"
os "iscsi"?

What is the advantage of the longer version?

Comment 3 Ben Marzinski 2018-06-20 19:12:33 EDT

You can also blacklist other protocols like "nvme" or "dasd". Right now, only "scsi" has multiple transport methods, but in the future multipath will likely need to distinguish between different "nvme" transports as well. This makes it easier to specify exactly what you want to blacklist.  It also maps onto how multipath internally distinguishes between device types.

Comment 4 Ben Marzinski 2018-06-20 19:23:32 EDT

The full list of protocol/transports that multipath recognizes and are available for blacklisting is:

scsi:fcp
scsi:spi
scsi:ssa
scsi:sbp
scsi:srp
scsi:iscsi
scsi:sas
scsi:adt
scsi:ata
ccw
cciss
nvme

Comment 5 Ben Marzinski 2018-06-20 19:29:19 EDT

oops. There's also "scsi:unspec" for scsi devices that don't have a detected transport (like scsi_debug) and "undef" for devices that don't have a detected protocol at all. Mostly, these are already caught by devnode or property blacklisting, but it is valid to run multipath on devices that don't have a detected procotol. Multipath just doesn't do any protocol specific actions on them.

Comment 6 Nir Soffer 2018-06-21 11:14:12 EDT

Thanks Ben, it makes sense. I hope that all this info will be in multipath.conf
manual.

Comment 7 Ben Marzinski 2018-06-22 14:00:45 EDT

Hopefully, this should work for you. Here's the information from the manpage:

blacklist section:

       protocol         Regular expression of the protocol to be excluded. See
                        below for a list of recognized protocols


       The  protocol strings that multipath recognizes are scsi:fcp, scsi:spi,
       scsi:ssa, scsi:sbp, scsi:srp, scsi:iscsi, scsi:sas, scsi:adt, scsi:ata,
       scsi:unspec,  ccw, cciss, nvme, and undef.  The protocol that a path is
       using can be viewed by running 'multipathd show paths format "%d %P"'


blacklist_exceptions section:

       protocol         Regular expression of the protocol to be  whitelisted.
                        See  the  blacklist  section  for a list of recognized
                        protocols

Comment 9 Ala Hino 2018-07-09 01:43:05 EDT

Ben,

Two questions please:
Could this be backported to RHEL 7.5?
Could this be pushed to Fedora 28?

Comment 10 Ben Marzinski 2018-07-12 14:07:38 EDT

Yeah. I think so. The change is pretty self contained. Obviously, the 7.5 change would need to get approved as a zstream. Could you open bugzillas for this?

Comment 12 Steve Almy 2018-07-23 12:48:28 EDT

*** Bug 1600672 has been marked as a duplicate of this bug. ***

Comment 26 errata-xmlrpc 2018-10-30 07:27:36 EDT

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:3236

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