bp1081 openstack eql paper

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Best Practices for EqualLogic in anOpenStack Private CloudA Dell EqualLogic best practices paper

Dell Storage EngineeringOctober 2014


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2 BP1081 | Best Practices for EqualLogic in an OpenStack Private Cloud

Revisions

Date Description

October 2014 Initial release

THIS WHITE PAPER IS FOR INFORMATIONAL PURPOSES ONLY, AND MAY CONTAIN TYPOGRAPHICAL ERRORS AND

TECHNICAL INACCURACIES. THE CONTENT IS PROVIDED AS IS, WITHOUT EXPRESS OR IMPLIED WARRANTIES OF

ANY KIND.

2014 Dell Inc. Confidential. All rights reserved. Reproduction of this material in any manner whatsoever without the

express written permission of Dell Inc. is strictly forbidden. For more information, contact Dell.

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PowerConnect, OpenManage, EqualLogic, Compellent, KACE, FlexAddress, Force10 and Vostro are

trademarks of Dell Inc. Other Dell trademarks may be used in this document. Cisco Nexus, Cisco MDS, Cisco NX-

0S, and other Cisco Catalystare registered trademarks of Cisco System Inc. EMC VNX, and EMC Unisphereare

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Table of contentsRevisions ......................................... ............................................... ............................................. ............................................... .............. 2

Acknowledgements ............................................................................................................................................................................. 4

Feedback ................................................................................................................................................................................................ 4

Executive summary .............................................................................................................................................................................. 4

1 Introduction ............................................ .............................................. .............................................. ............................................. 5

1.1

Audience ............................................... .............................................. .............................................. ..................................... 5

2 OpenStack storage concepts ..................................................................................................................................................... 6

2.1

Nova ephemeral storage .................................................................................................................................................. 6

2.2 Swift object storage ........................................................................................................................................................... 6

2.3

Cinder block storage ......................................................................................................................................................... 6

3 Cinder block storage service ........................................................................... ............................................... ............................. 7

3.1

EqualLogic driver for Cinder ............................................................................................................................................ 8

3.2 Driver functions .................................................................................................................................................................. 9

4 Installing EqualLogic as Cinder back-end storage .............................................. .............................................. ................... 10

4.1 Prerequisites ....................................................................................................................................................................... 11

4.2 OpenStack network traffic types ................................................................................................................................... 11

4.3 Configuring Cinder ......................................................................... ............................................... ................................... 13

4.4 Adding an EqualLogic array member .......................................... ............................................... ...................................14

4.5

Using more than one EqualLogic group or pool .......................................................................................................14

4.6

When to use the Cinder LVM driver ............................................ ............................................... ................................... 17

5 EqualLogic MPIO ..........................................................................................................................................................................19

6 Conclusion .............................................. .............................................. .............................................. .......................................... 23

A

Test configuration details ........................................... .............................................. .............................................. ................... 24

B Additional Resources ........................................... ............................................... .............................................. .......................... 25


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Acknowledgements

This best practice white paper was produced by the following members of the Dell Storage team:

Engineering: Clay Cooper

Editing: Camille Daily

Feedback

We encourage readers of this publication to provide feedback on the quality and usefulness of this

information by sending an email [email protected].

Executive summary

This paper provides an overview of and best practices for using an EqualLogic PS Series storage group as

back-end storage for the OpenStack Cinder block storage service.

[email protected]
mailto:[email protected]:[email protected]?subject=BP1066%20|%20Red%20Hat%20Enterprise%20Linux%206.3%20NIC%20Optimizationmailto:[email protected]?subject=BP1066%20|%20Red%20Hat%20Enterprise%20Linux%206.3%20NIC%20Optimizationmailto:[email protected]?subject=BP1066%20|%20Red%20Hat%20Enterprise%20Linux%206.3%20NIC%20Optimizationmailto:[email protected]?subject=BP1066%20|%20Red%20Hat%20Enterprise%20Linux%206.3%20NIC%20Optimizationmailto:[email protected]?subject=BP1066%20|%20Red%20Hat%20Enterprise%20Linux%206.3%20NIC%20Optimizationmailto:[email protected]?subject=BP1066%20|%20Red%20Hat%20Enterprise%20Linux%206.3%20NIC%20Optimizationmailto:[email protected]?subject=BP1066%20|%20Red%20Hat%20Enterprise%20Linux%206.3%20NIC%20Optimizationmailto:[email protected]:[email protected]?subject=BP1066%20|%20Red%20Hat%20Enterprise%20Linux%206.3%20NIC%20Optimizationmailto:[email protected]?subject=BP1066%20|%20Red%20Hat%20Enterprise%20Linux%206.3%20NIC%20Optimization


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1 IntroductionOpenStack is a suite of services running on Linux server nodes that provide Infrastructure as a Service

(IaaS) by provisioning virtualized compute instances and networks from a pool of heterogeneous

enterprise hardware. OpenStack also makes block and object storage available to the compute instances

through the Cinder block storage service and the Swift object store service.

Dell EqualLogic PS Series arrays provide a storage solution that delivers the benefits of consolidated

networked storage in a self-managing iSCSI storage area network (SAN) that is affordable and easy to use,

regardless of scale. Built on an advanced, peer storage architecture, EqualLogic storage simplifies the

deployment and administration of consolidated storage environments, enabling:

Perpetual self-optimization with automated load balancing across disks, RAID sets, connections,

cache and controllers.

Efficient enterprise scalability for both performance and capacity without forklift upgrades.

Powerful, intelligent and simplified management.

This technical paper serves as a guide to the effective utilization of EqualLogic PS Series storage in anOpenStack private cloud.

1.1

AudienceThis technical white paper is for storage administrators, SAN system designers, storage consultants, or

anyone tasked with building an OpenStack private cloud that includes EqualLogic PS Series storage. It is

assumed that all readers have experience designing, deploying and administering an OpenStack private

cloud and shared storage solutions. Also, there are some assumptions made in terms of familiarity with all

current Ethernet standards as defined by the IEEE (Institute of Electrical and Electronic Engineers) as well

as TCP/IP (Transmission Control Protocol/Internet Protocol) and iSCSI standards as defined by the IETF

(Internet Engineering Task Force).


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2 OpenStack storage conceptsIt is important to understand the types of storage available to the compute instances in an OpenStack

cloud and which services provide them. Section2 explains the characteristics and purpose of each storage

type as well as what storage hardware is best suited to provide the raw storage.

2.1

Nova ephemeral storageEphemeral storage gets its name from the fact that it does not persist beyond the lifecycle of the compute

instance with which it is associated. It is the virtual disk or disks created by the OpenStack Nova compute

service at the time of compute instance provisioning. The virtual disks are created in the file system

underlying the Nova node hypervisor, usually on storage local to the Nova node, and are typically tens of

GBs in size.

For persistent storage, compute instances use block storage volumes provided by the OpenStack Cinder

service or the OpenStack Swift object store.

2.2

Swift object storageThe OpenStack Swift object store is a highly scalable, redundant, distributed storage system for static,

unstructured data sets such as content delivery networks or cold storage archives. It is also the default

storage location for OpenStack Cinder backups and OpenStack Glance images.

Typically Swift object stores are very large, in the tens of TBs. Data replication and availability are handled

by Swift using replica-based, location-aware redundancy. Swift is optimized for local commodity HDD and

hardware RAID is not required or recommended. While this is a good fit for HDD in or directly attached to

the Swift server node, it is not a good fit for traditional SAN storage systems that already provide robust

data protection mechanisms such as RAID, snapshots, and replication.

2.3

Cinder block storageThe OpenStack Cinder block storage service provides volumes to the compute instances for persistent

secondary storage. Each Cinder volume can be attached to only one compute instance at a time, but a

compute instance can have multiple attached volumes. OpenStack even supports provisioning compute

instances to boot directly from Cinder volumes rather than from ephemeral disks.

Cinder nodes can utilize all types of raw storage when provisioning volumes. Storage within or directly

attached to the Cinder nodes themselves, network file system or NAS devices, and hardware or software

SAN storage systems can all be used as back-end storage.

Since Cinder relies on the data protection mechanisms provided by the back-end storage system, SANstorage systems such as EqualLogic PS Series are an excellent fit.


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3 Cinder block storage serviceBy default, Cinder uses the LVM driver to provision volumes within raw storage local to the Cinder node. It

uses Linux logical volume management (LVM) to create volumes within the raw storage and then makes

them available to the Nova node using Linux iSCSI target software. The Nova node connects to the Cinder

node volumes using the Linux iSCSI initiator then the Nova node hypervisor presents those volumes to the

compute instances as virtual disks.

Making the Cinder volumes available to the compute instances is a two-step process. First, the volumes

are created by the Cinder service. Once created, the volumes can then be attached to specific compute

instances. iSCSI connections will not be initiated until the volume is attached to the compute instance.

Notice that in this scenario, the Cinder node is in the data path.

Figure 1 Logical diagram of the Cinder block storage service using the default LVM driver and localstorage


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3.1

EqualLogic driver for CinderThe Cinder block storage service has the capability to use other drivers, also called plugins, which enable

the Cinder node to provision volumes directly onto external storage systems. A driver for EqualLogic is

included in the OpenStack distribution as of the Havana release, on which Red Hat Enterprise Linux

OpenStack Platform 4 is based.

The EqualLogic driver, eqlx.py, is written in Python like the rest of OpenStack. The driver allows the Cinder

node to handle the control plane functions of volume administration and access control by connecting to

the management interface of the EqualLogic storage group via Secure Shell (SSH). One benefit of the

EqualLogic driver is that the Cinder node is taken out of the production data path and the Nova node

connects directly to the EqualLogic storage volumes using iSCSI.

One thing to note is that the Cinder node (rather than the Nova node) will make an iSCSI connection to

the EqualLogic storage group when creating Glance images from volumes or volumes from Glance

images, or when backing up volumes to an object store such as Swift.

Figure 2 Logical diagram of the Cinder block storage service using the EqualLogic driver and a PS Seriesstorage group


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3.2

Driver functionsAs mentioned, the EqualLogic driver gives Cinder the ability to initiate volume administration tasks at the

EqualLogic storage group using the management interface.

The following functions are direct calls to native EqualLogic functions:

Volume create and delete

Volume attach to and detach from a compute instance

- Access rules are assigned to the volume that grants access to the IQN of the Nova node iSCSI

initiator, or to a set of credentials when using CHAP

Snapshot create and delete

Create volume from snapshot

Get volume information

Clone volume

Extend volume

The following functions are generic volume actions performed by the Cinder node that do not leverage

native EqualLogic functionality. They require iSCSI connectivity from the Cinder node to the EqualLogic

storage:

Create volume from Glance image

Create Glance image from volume

Volume backup to an object store


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4 Installing EqualLogic as Cinder back-end storageSection 4 outlines the tasks and considerations involved in configuring the Cinder block storage service to

use an EqualLogic PS Series storage group as back-end storage for provisioning volumes.Figure 3

illustrates the test environment used to analyze EqualLogic driver function and best practices.

Figure 3 The OpenStack private cloud test environment with EqualLogic PS Series storage


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4.1

PrerequisitesThe instructions below assume the following:

A fully deployed OpenStack private cloud using Red Hat Enterprise Linux 6.5 and OpenStack

Platform 5 (based on the OpenStack Icehouse release) including running Nova and Cinder services.

RHN access configured on each node, including the following RHN channels:- rhel-x86_64-server-6-ost-5

- rhel-x86_64-server-6

- rhel-x86_64-server-6-ost-foreman

An initialized and configured EqualLogic PS Series storage group.

Proper network connectivity among the OpenStack nodes and the EqualLogic storage group. See

Section 4.2 for more detail on network connectivity requirements.

The Linux iSCSI initiator installed on the Nova and Cinder nodes.

yum install iscsi-initiator-utils

Update the python-paramiko RPM on the Cinder node to avoid an SSH failure when connecting to

the EqualLogic storage.

yum update python-paramiko

For more information, see the following Cinder bug:https://bugs.launchpad.net/cinder/+bug/1150720

Properly configured SAN interface on Nova and Cinder nodes.

For SAN interface configuration best practices in Red Hat Enterprise Linux, see RHEL 6.3 NIC optimization

and best practices with EqualLogic SANs:

http://en.community.dell.com/techcenter/extras/m/white_papers/20438152.aspx

4.2

OpenStack network traffic typesThere are many types of network traffic in an OpenStack cloud. Logical isolation is important for some

network traffic types, such as the PXE-based bare metal provisioning of OpenStack nodes, while other

types of network traffic can be converged depending on the hardware available and the performance

required. The following is a list of potential networks in an OpenStack cloud.

PXE networkfor bare metal provisioning of OpenStack nodes.

Public networkfor compute instances to access the internet using assigned floating IP addresses.

The public network also allows end users to access the OpenStack service APIs on the nodes.

Management networkfor inter-node communication including database traffic, message queuing

and HA protocols. Storage network(SAN) for iSCSI traffic between the Nova nodes and the Cinder nodes or external

storage systems.

Private networkfor connectivity among compute instances using fixed IP addresses.
https://bugs.launchpad.net/cinder/+bug/1150720https://bugs.launchpad.net/cinder/+bug/1150720https://bugs.launchpad.net/cinder/+bug/1150720http://en.community.dell.com/techcenter/extras/m/white_papers/20438152.aspxhttp://en.community.dell.com/techcenter/extras/m/white_papers/20438152.aspxhttp://en.community.dell.com/techcenter/extras/m/white_papers/20438152.aspxhttps://bugs.launchpad.net/cinder/+bug/1150720


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Out-of-band network for access to server, storage and switch management interfaces and remote

access controllers.

Figure 4 illustrates the network connectivity as implemented in the simplified test environment. It consists

of the following networks.

A Management networkfor inter-node communication and for the hardware management

interfaces. This network also serves as the public network

A SANfor the iSCSI traffic among the OpenStack nodes and the EqualLogic storage group

A private networkfor connectivity among the compute instances

Figure 4 Network connectivity requirements for the OpenStack nodes and the EqualLogic storagegroup


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4.3

Configuring CinderTo configure the Cinder block storage service, perform the following steps at the Cinder node.

1.

Edit /etc/cinder/cinder.conf to include the following parameters:

[DEFAULT]

volume_driver=cinder.volume.drivers.eqlx.DellEQLSanISCSIDriver

san_ip=IP_EQLX

san_login=SAN_UNAME

san_password=SAN_PW

eqlx_group_name=EQLX_GROUP

eqlx_pool=EQLX_POOL

Other optional parameters:

san_thin_provision=true|false

eqlx_use_chap=true|false

eqlx_chap_login=EQLX_UNAME

eqlx_chap_password=EQLX_PW

eqlx_cli_timeout=30

eqlx_cli_max_retries=5

san_ssh_port=22

ssh_conn_timeout=30

san_private_key=SAN_KEY_PATH

ssh_min_pool_conn=1

ssh_max_pool_conn=5

For more information on configuring the Cinder EqualLogic driver, see the official RHEL OpenStack

platform documentation see: https://access.redhat.com/documentation/en-

US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_vo

lume-drivers.html#dell-equallogic-driver

2. Restart the Cinder volume service.

/etc/init.d/openstack-cinder-volume restart

3. Look for driver initialization success in the Cinder volume log file.
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driver


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grep 'EQL-driver: Setup is complete' /var/log/cinder/volume.log

4.4

Adding an EqualLogic array memberArray members can be added to an EqualLogic PS Series group at any time, up to the group maximum of

16 array members. Once added to the group, assign the array member to the pool that the Cinder

EqualLogic driver is configured to use in /etc/cinder/cinder.conf.

The Cinder EqualLogic driver regularly checks for pool status, once a minute by default. New space

available to the pool will be automatically detected.

4.5

Using more than one EqualLogic group or poolThe Cinder block storage service can be configured to make multiple back-end storage types available for

volume provisioning. This means that more than one EqualLogic group and/or pool can be used as back-

end storage for the same Cinder service. Below is an example of a cinder.conf file that configures two

EqualLogic groups as two separate Cinder storage back-ends.

[DEFAULT]

enabled_backends=backend1,backend2

san_ssh_port=22

ssh_conn_timeout=30

[backend1]


volume_backend_name=backend1

san_ip=IP_EQLX1

san_login=SAN_UNAME

san_password=SAN_PW


eqlx_pool=EQLX_POOL

[backend2]



san_ip=IP_EQLX2


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san_login=SAN_UNAME

san_password=SAN_PW


eqlx_pool=EQLX_POOL

Once the back-ends are configured in cinder.conf and activated by restarting the Cinder volume service,

they can be associated with a volume type and then chosen during volume provisioning.

To associate a back-end to a volume type:

cinder type-create EQL-group-1

cinder type-key EQL-group-1 set volume_backend_name=backend1

Volume types can be useful for differentiating between EqualLogic storage groups or pools with different

performance profiles. For example, array members with SATA HDD versus those with SSD array members.

It is also possible to add more than one EqualLogic group or pool to the same back-end storage type. Thismight be done when adding a second EqualLogic group or pool with an identical performance profile.

Notice that in the cinder.conf below, there are still two different EqualLogic groups but now with a single

back-end name.

[DEFAULT]

enabled_backends=backend1

san_ssh_port=22

ssh_conn_timeout=30

[backend1]



san_ip=IP_EQLX1

san_login=SAN_UNAME

san_password=SAN_PW


eqlx_pool=EQLX_POOL

[backend2]


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san_ip=IP_EQLX2

san_login=SAN_UNAME

san_password=SAN_PW


eqlx_pool=EQLX_POOL

When more than one back-end storage is configured with the same back-end name, the Cinder Schedule

will determine which specific back-end on which to provision a volume by filtering based on availability

zones, capacity and capability and then choosing the back-end based on available capacity.

For more information on configuring multiple back-end storage types see:

https://access.redhat.com/documentation/en-

US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manag

e-volumes.html#multi_backend
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backend


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4.6

When to use the Cinder LVM driverIt is possible to use the Cinder LVM driver with an EqualLogic PS Series Group and there are use cases for

doing so. EqualLogic storage pools require at least one array member, and an array member can only be a

member of one pool at a time. So dedicating a storage pool to Cinder requires a dedicated array member.

It is technically possible for Cinder to share a storage pool with another solution. Cinder is only aware (inits database) of the volumes it creates, and will not delete or attempt to attach compute instances to other

volumes that may already exist. The Cinder EqualLogic driver checks the available space of the storage

pool prior to creating each volume and presents an error if there is insufficient free space in the pool.

Space available for Cinder volumes can further be limited by quota.

However, if multiple Cinder back-ends are required and only one EqualLogic array member is available,

the Cinder LVM driver can be used instead. By creating very large volumes and connecting the Cinder

node to them using iSCSI, the Cinder LVM driver can provision volumes within them as it would with local

or direct attached storage. See Figure 1 for a logical diagram of the Cinder LVM driver in use.

1. At the EqualLogic storage:

a.

Create two very large volumes.

b.

Setup rules to allow access by the Cinder node.

2. At the Cinder node:

a. Install Host Integration Tools for Linux for MPIO to the volumes.

b. Login to the target volumes.

c.

Identify the multipath device for each volume in /dev/eql/.

d. Initialize volumes as LVM physical volumes.

pvcreate /dev/eql/volume1

pvcreate /dev/eql/volume2

3.

Create an LVM volume group on each volume.vgcreate cinder-volumes-1

vgcreate cinder-volumes-2

4.

Edit /etc/cinder/cinder.conf to contain the lines below.

5. Edit /etc/lvm/lvm.conf to set issue_discards = 1 to pass Linux TRIM and SCSI UNMAP commands

to the EqualLogic storage, freeing up space as Cinder volumes are de-provisioned.

6.

/etc/init.d/openstack-cinder-volume restart

[DEFAULT]

enabled_backends=lvmdriver-1,lvmdriver-2

[lvmdriver-1]

volume_group=cinder-volumes-1

volume_driver=cinder.volume.drivers.lvm.LVMISCSIDriver


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volume_backend_name=LVM_iSCSI

[lvmdriver-2]

volume_group=cinder-volumes-2

volume_driver=cinder.volume.drivers.lvm.LVMISCSIDriver

volume_backend_name=LVM_iSCSI


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5 EqualLogic MPIOMulti-path I/O to EqualLogic volumes from OpenStack nodes is currently not supported and is not

enabled with the default Nova configuration in RHEL OSP 5. However, it is technically possible to enable

iSCSI multipath I/O on a particular compute instance using the following steps. It is recognized that these

steps are not friendly to the OpenStack workflow. They are provided as a guide for OpenStack developers

to fully enable EqualLogic MPIO in the future.

1.

Make the following change to /etc/nova/nova.conf.

iscsi_use_multipath=true

2. Restart the Nova API and compute services at the nodes running each service.

/etc/init.d/openstack-nova-api restart

/etc/init.d/openstack-nova compute restart

Linux multipathd will not be used to enable multi-path I/O to EqualLogic volumes. However, currently

Nova code requires multipathd, specifically the multipath utility, to be installed when iSCSI multipath is setto true.

3.

Install, enable, and configure the native multipath application at the Nova node running the

compute service.

yum install device-mapper-multipath

mpathconf --enable

mpathconf --find_multipaths y

Host Integration Tools (HIT) for Linux provide EqualLogic recommended multi-path (MPIO) functionality

by creating a multipath device for each volume and providing a kernel driver which together intelligently

direct I/O to the volume slices on the correct EqualLogic array members. HIT for Linux also provides

command-line tools for discovering and connecting to EqualLogic volumes and a performance tuning

system check. Follow the instructions below to install HIT for Linux.

4. Install the HIT for Linux at the Nova node running the compute service.

a.

Download the latest HIT for Linux ISO from the Dell EqualLogic support site (login required).

i. https://eqlsupport.dell.com/secure/login.aspx

b. Mount the ISO image from within Linux.

c. Change to the directory of the ISO mount point, for example:

cd /media/CDROM

d.

Run the HIT for Linux installer script.

./install --nogpgcheck

e.

Follow the instructions, choosing to include only the SAN interface subnets.


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Eqltune, the EqualLogic performance tuning utility, will be run automatically by the HIT for Linux

installer. This utility will detect and fix problematic settings for block devices, Ethernet adapters,

sysctl tunable options, and more. Most importantly, it configures RHEL 6 to allow I/O over multiple

interfaces on the same SAN subnet. Eqltune will record and can, if necessary, restore the original

configuration. Run eqltune from the command line for further information.

f.

Once complete, include into the shell the HIT bash configuration file for command line

completion of EqualLogic tools. Note the space between the period and the full path.

. /etc/bash_completion.d/equallogic

5. Using the Horizon web interface:

a.

Create a volume on the EqualLogic group.

b. Attach the volume to a running compute instance.

6.

At the Nova node hosting the compute instance, multiple iSCSI sessions can be observed. Initially,

one iSCSI session per SAN interface will be created. HIT will monitor the volume sessions and will

create additional sessions if the volume is distributed across more than one array member. For

example, if the volume is distributed across two array members, HIT will ensure that four iSCSI

sessions are created. Use the following command to view current iSCSI sessions.

iscsiadm m session

7.

Unfortunately, Nova references a single path device node when adding the virtual disk to the

compute instance and I/O will not be distributed across the multiple iSCSI sessions. Correcting this

requires identifying the multipath device created by HIT for the volume and modifying the

compute instance configuration file to reference it. This can be done with the following steps.

a.

List the Cinder volumes and identify the volume attached to the compute instance.

cinder list

b.

Find the EqualLogic multipath device that corresponds to this volume.

ls -al /dev/eql/

c. Find the Nova ID of the compute instance.

nova list

d. Find the KVM domain name of the compute instance.

nova show

...

OS-EXT-SRV-ATTR:instance_name | instance-00000005

...

e. Find the KVM domain ID of the compute instance using the KVM domain name.


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virsh list

f.

Find the correct virtual disk.

virsh domblklist

g. Edit the KVM domain configuration file for the compute instance and change the source

device of the virtual disk to the EqualLogic multipath device.

virsh edit

Before:

b03dc257-8b01-41e9-bf8a-8c0a0a28047f

After:

37283b00-b81c-4298-a9ef-353d6a2eabe5


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h.

Restart the compute instance.


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6 ConclusionCinder block storage is an important component of an OpenStack private cloud, providing persistent

storage or bootable volumes for Nova compute instances.

A Cinder driver, also called a plugin, specifically for EqualLogic is included in the community distribution of

OpenStack as of the Havana release. The driver allows an EqualLogic PS Series storage group to serve asback-end storage for the Cinder. The Cinder service can provision volumes on the EqualLogic group

automatically, allowing the Nova node to connect directly to the storage group using iSCSI on behalf of

the compute instances.

Configuring Cinder to use EqualLogic as back-end storage is a very straightforward process. The

EqualLogic group can be easily scaled out without the need for Cinder reconfiguration. The Cinder service

can utilize multiple array members or pools per storage group, and even supports multiple groups. Pools

or groups with different performance profiles can be differentiated using Cinder volume typing which

allows end users to choose backend storage types at the time of volume creation within the Horizon

interface.

While EqualLogic MPIO does not work out of the box, it can be enabled on a per compute instance basis

The steps are provided as a guide to future OpenStack development.


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A Test configuration detailsHardware Description

Blade enclosure (1) Dell PowerEdge M1000e chassis:

CMC firmware: 4.5

Blade servers (2) Dell PowerEdge M620 server (Cinder nodes):

RedHat Enterprise Linux 6.5 x86_64

RHEL OpenStack Platform 5

BIOS version: 2.2.7

iDRAC firmware: 1.56.55

(2) Intel Xeon E5-2620

16GB RAM

Dual port Intel x520-k 10GbE CNADriver: 3.17.3Firmware: 15.0.28

(2) Dell PowerEdge M820 server (Nova nodes):

RedHat Enterprise Linux 6.5 x86_64 RHEL OpenStack Platform 5

BIOS version: 2.0.24


(4) Intel Xeon E5-4620

256GB RAM

Dual port Intel x520-k 10GbE CNADriver: 3.17.3Firmware: 15.0.28

Dell EqualLogic Host Integration Tools for Linux 1.3.0

Rack servers (2) Dell PowerEdge R620 server (RHOS Manager):

RedHat Enterprise Linux 6.5 x86_64

RHEL OpenStack Platform 5 BIOS version: 2.2.2


(2) IntelXeonE5-2650

64GB RAM

Dual port Broadcom BCM57810 10GbE CNADriver: 1.72.51-0Firmware: 7.8.53

Blade I/O modules (2) Dell 10Gb Ethernet Pass-through module

SAN switches (2) Dell Force10 s4810

Firmware: 9.3.0.0

SAN array members (2) Dell EqualLogic PS6210

(2) 10GbE network adapters

(24) SED Seagate ST900MM0036 900GB 10KFirmware: LEF5Firmware: 7.0.3


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B Additional Resources

EqualLogic Configuration Guide:

http://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19852516/download.aspx

EqualLogic Compatibility Matrix (ECM):http://en.community.dell.com/techcenter/storage/w/wiki/2661.equallogic-compatibility-

matrix.aspx

EqualLogic Switch Configuration Guides:

http://en.community.dell.com/techcenter/storage/w/wiki/4250.switch-configuration-guides-by-

sis.aspx

The latest EqualLogic firmware updates and documentation (site requires a login):

http://support.equallogic.com

Official RHEL OpenStack platform documentation:

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/sect

ion_volume-drivers.html#dell-equallogic-driver

https://access.redhat.com/documentation/en-

US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_

manage-volumes.html#multi_backend

RHEL 6.3 NIC optimization and best practices with EqualLogic SANs:

http://en.community.dell.com/techcenter/extras/m/white_papers/20438152.aspx

Dell Tech Center Storage page:

http://en.community.dell.com/techcenter/storage/
http://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19852516/download.aspxhttp://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19852516/download.aspxhttp://en.community.dell.com/techcenter/storage/w/wiki/2661.equallogic-compatibility-matrix.aspxhttp://en.community.dell.com/techcenter/storage/w/wiki/2661.equallogic-compatibility-matrix.aspxhttp://en.community.dell.com/techcenter/storage/w/wiki/2661.equallogic-compatibility-matrix.aspxhttp://en.community.dell.com/techcenter/storage/w/wiki/4250.switch-configuration-guides-by-sis.aspxhttp://en.community.dell.com/techcenter/storage/w/wiki/4250.switch-configuration-guides-by-sis.aspxhttp://en.community.dell.com/techcenter/storage/w/wiki/4250.switch-configuration-guides-by-sis.aspxhttp://support.equallogic.com/http://support.equallogic.com/https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttp://en.community.dell.com/techcenter/extras/m/white_papers/20438152.aspxhttp://en.community.dell.com/techcenter/extras/m/white_papers/20438152.aspxhttp://en.community.dell.com/techcenter/storage/http://en.community.dell.com/techcenter/storage/http://en.community.dell.com/techcenter/storage/http://en.community.dell.com/techcenter/storage/http://en.community.dell.com/techcenter/storage/http://en.community.dell.com/techcenter/extras/m/white_papers/20438152.aspxhttp://en.community.dell.com/techcenter/extras/m/white_papers/20438152.aspxhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Cloud_Administrator_Guide/section_manage-volumes.html#multi_backendhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttps://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/5/html/Configuration_Reference_Guide/section_volume-drivers.html#dell-equallogic-driverhttp://support.equallogic.com/http://en.community.dell.com/techcenter/storage/w/wiki/4250.switch-configuration-guides-by-sis.aspxhttp://en.community.dell.com/techcenter/storage/w/wiki/4250.switch-configuration-guides-by-sis.aspxhttp://en.community.dell.com/techcenter/storage/w/wiki/2661.equallogic-compatibility-matrix.aspxhttp://en.community.dell.com/techcenter/storage/w/wiki/2661.equallogic-compatibility-matrix.aspxhttp://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19852516/download.aspx

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