openstack/cinder
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cinder/doc/source/configuration/block-storage/drivers/emc-vmax-driver.rst
Helen Walsh b6d031ae39 VMAX doc - Queens feature documentation 
Part 3 - Legacy information removal and typo fixes

Change-Id: Ic220cda12c3a7eb78274e8ee9a12384baa5e69d3
Partial-Bug: #1737735
2018-01-12 10:42:00 +00:00

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Dell EMC VMAX iSCSI and FC drivers

The Dell EMC VMAX drivers, VMAXISCSIDriver and VMAXFCDriver, support the use of Dell EMC VMAX storage arrays with the Cinder Block Storage project. They both provide equivalent functions and differ only in support for their respective host attachment methods.

The drivers perform volume operations by communicating with the back-end VMAX storage management software. They use the Requests HTTP library to communicate with a Unisphere for VMAX instance, using a RESTAPI interface in the backend to perform VMAX storage operations.

System requirements

The Dell EMC VMAX Cinder driver supports the VMAX-3 hybrid series and VMAX All-Flash arrays.

The array operating system software, Solutions Enabler 8.4.0.7 or later, and Unisphere for VMAX 8.4.0.15 or later are required to run Dell EMC VMAX Cinder driver.

You can download Solutions Enabler and Unisphere from the Dell EMC's support web site (login is required). See the Solutions Enabler 8.4.0 Installation and Configuration Guide and Unisphere for VMAX 8.4.0 Installation Guide at support.emc.com.

Required VMAX software suites for OpenStack

There are five Dell EMC Software Suites sold with the VMAX All Flash and Hybrid arrays:

  • Base Suite
  • Advanced Suite
  • Local Replication Suite
  • Remote Replication Suite
  • Total Productivity Pack

The Dell EMC VMAX Cinder driver requires the Advanced Suite and the Local Replication Suite or the Total Productivity Pack (it includes the Advanced Suite and the Local Replication Suite) for the VMAX All Flash and Hybrid.

Using VMAX Remote Replication functionality will also require the Remote Replication Suite.

The storage system also requires a Unisphere for VMAX (SMC) eLicence.

Each are licensed separately. For further details on how to get the relevant license(s), reference eLicensing Support below.

eLicensing support

To activate your entitlements and obtain your VMAX license files, visit the Service Center on https://support.emc.com, as directed on your License Authorization Code (LAC) letter emailed to you.

  • For help with missing or incorrect entitlements after activation (that is, expected functionality remains unavailable because it is not licensed), contact your EMC account representative or authorized reseller.

  • For help with any errors applying license files through Solutions Enabler, contact the Dell EMC Customer Support Center.

  • If you are missing a LAC letter or require further instructions on activating your licenses through the Online Support site, contact EMC's worldwide Licensing team at licensing@emc.com or call:

    North America, Latin America, APJK, Australia, New Zealand: SVC4EMC (800-782-4362) and follow the voice prompts.

    EMEA: +353 (0) 21 4879862 and follow the voice prompts.

Supported operations

VMAX drivers support these operations:

  • Create, list, delete, attach, and detach volumes
  • Create, list, and delete volume snapshots
  • Copy an image to a volume
  • Copy a volume to an image
  • Clone a volume
  • Extend a volume
  • Retype a volume (Host and storage assisted volume migration)
  • Create a volume from a snapshot
  • Create and delete generic volume group
  • Create and delete generic volume group snapshot
  • Modify generic volume group (add and remove volumes)
  • Create generic volume group from source
  • Live Migration
  • Volume replication SRDF/S, SRDF/A and SRDF Metro
  • Quality of service (QoS)
  • Manage and unmanage volumes and snapshots

VMAX drivers also support the following features:

  • Dynamic masking view creation
  • Dynamic determination of the target iSCSI IP address
  • iSCSI multipath support
  • Oversubscription
  • Service Level support
  • SnapVX support
  • Compression support(All Flash only)
  • CHAP Authentication

Note

VMAX All Flash array with Solutions Enabler 8.3.0.11 or later have compression enabled by default when associated with Diamond Service Level. This means volumes added to any newly created storage groups will be compressed.

VMAX Driver Integration

  1. Download Solutions Enabler from support.emc.com and install it.

    You can install Solutions Enabler on a non-OpenStack host. Supported platforms include different flavors of Windows, Red Hat, and SUSE Linux. Solutions Enabler can be installed on a physical server, or as a Virtual Appliance (a VMware ESX server VM). Additionally, starting with HYPERMAX OS Q3 2015, you can manage VMAX3 arrays using the Embedded Management (eManagement) container application. See the Solutions Enabler 8.4.0 Installation and Configuration Guide on support.emc.com for more details.

    Note

    You must discover storage arrays before you can use the VMAX drivers. Follow instructions in Solutions Enabler 8.4.0 Installation and Configuration Guide on support.emc.com for more details.

  2. Download Unisphere from support.emc.com and install it.

    Unisphere can be installed in local, remote, or embedded configurations

    - i.e., on the same server running Solutions Enabler; on a server connected to the Solutions Enabler server; or using the eManagement container application (containing Solutions Enabler and Unisphere for VMAX). See Unisphere for VMAX 8.4.0 Installation Guide at support.emc.com.

  3. Configure Block Storage in cinder.conf

    Note

    For security and backend uniformity, the use of the XML file for VMAX backend configuration has been deprecated in Queens. While the xml file usage will still be supported, a warning will be issued on its impending deprecation.

    VMAX parameter cinder.conf parameter Default Required Description

    RestServerIp

    		 san_ip " Yes IP address of the Unisphere server

    RestServerPort

    		 san_rest_port 8443 No Port of the Unisphere server

    RestUserName

    		 san_login 'admin' Yes Username of the Unisphere server

    RestPassword

    		 san_password " Yes Password of the Unisphere server

    Array

    		 vmax_array None Yes Unique VMAX array serial number

    SRP

    		 vmax_srp None Yes Name of the storage resource pool

    PortGroups

    		 vmax_port_groups None Yes The name(s) of VMAX port group(s)

    SSLVerify

    		 driver_ssl_cert_verify driver_ssl_cert_path False None No No The path to the my_unisphere_host.pem

    Note

    VMAX PortGroups must be pre-configured to expose volumes managed by the array. Port groups can be supplied in the cinder.conf, or can be specified as an extra spec storagetype:portgroupname on a volume type. The latter gives the user more control. When a dynamic masking view is created by the VMAX driver, if there is no port group specified as an extra specification, the port group is chosen randomly from the PortGroup list, to evenly distribute load across the set of groups provided.

    Note

    Service Level and workload can be added to the cinder.conf when the backend is the default case and there is no associated volume type. This not a recommended configuration as it is too restrictive.

    VMAX parameter cinder.conf parameter Default Required

    ServiceLevel

    		 vmax_service_level None No

    Workload

    		 vmax_workload None No

    Configure Block Storage in cinder.conf

    Add the following entries to /etc/cinder/cinder.conf:

    enabled_backends = CONF_GROUP_ISCSI, CONF_GROUP_FC

[CONF_GROUP_ISCSI]
volume_driver = cinder.volume.drivers.dell_emc.vmax.iscsi.VMAXISCSIDriver
volume_backend_name = VMAX_ISCSI_DIAMOND
vmax_port_groups = [OS-ISCSI-PG]
san_ip = 10.10.10.10
san_login = my_username
san_password = my_password
vmax_array = 000123456789
vmax_srp = SRP_1


[CONF_GROUP_FC]
volume_driver = cinder.volume.drivers.dell_emc.vmax.fc.VMAXFCDriver
volume_backend_name = VMAX_FC_DIAMOND
vmax_port_groups = [OS-FC-PG]
san_ip = 10.10.10.10
san_login = my_username
san_password = my_password
vmax_array = 000123456789
vmax_srp = SRP_1

    In this example, two back-end configuration groups are enabled: CONF_GROUP_ISCSI and CONF_GROUP_FC. Each configuration group has a section describing unique parameters for connections, drivers and the volume_backend_name.

  4. Create Volume Types

    Once the cinder.conf has been updated, openstack commands need to be issued in order to create and associate OpenStack volume types with the declared volume_backend_names.

    Additionally, each volume type will need an associated pool_name - an extra specification indicating the service level/ workload combination to be used for that volume type.

    There is also the option to assign a port group to a volume type by setting the storagetype:portgroupname extra specification.

    Note

    It is possible to create as many volume types as the number of Service Level and Workload(available) combination for provisioning volumes. The pool_name is the additional property which has to be set and is of the format: <ServiceLevel>+<Workload>+<SRP>+<Array ID>. This can be obtained from the output of the cinder get-pools--detail.

    $ openstack volume type create VMAX_ISCSI_SILVER_OLTP
$ openstack volume type set --property volume_backend_name=ISCSI_backend \
                            --property pool_name=Silver+OLTP+SRP_1+000123456789 \
                            --property storagetype:portgroupname=OS-PG2 \
                            VMAX_ISCSI_SILVER_OLTP
$ openstack volume type create VMAX_FC_DIAMOND_DSS
$ openstack volume type set --property volume_backend_name=FC_backend \
                            --property pool_name=Diamond+DSS+SRP_1+000123456789 \
                            --property storagetype:portgroupname=OS-PG1 \
                            VMAX_FC_DIAMOND_DSS

    By issuing these commands, the Block Storage volume type VMAX_ISCSI_SILVER_OLTP is associated with the ISCSI_backend, a Silver Service Level, and an OLTP workload.

    The type VMAX_FC_DIAMOND_DSS is associated with the FC_backend, a Diamond Service Level, and a DSS workload.

    The ServiceLevel manages the underlying storage to provide expected performance. Setting the ServiceLevel to None means that non-FAST managed storage groups will be created instead (storage groups not associated with any service level). If ServiceLevel is None then Workload must be None.

    openstack volume type set --property pool_name=None+None+SRP_1+000123456789

    When a Workload is added, the latency range is reduced due to the added information. Setting the Workload to None means the latency range will be the widest for its Service Level type. Please note that you cannot set a Workload without a Service Level.

    openstack volume type set --property pool_name=Diamond+None+SRP_1+000123456789

    Note

    VMAX Hybrid supports Optimized, Diamond, Platinum, Gold, Silver, Bronze, and NONE service levels. VMAX All Flash supports Diamond and None. Both support DSS_REP, DSS, OLTP_REP, OLTP, and None workloads.

Upgrading from SMI-S based driver to RESTAPI based driver

Seamless upgrades from an SMI-S based driver to RESTAPI based driver, following the setup instructions above, are supported with a few exceptions:

  1. Live migration functionality will not work on already attached/in-use legacy volumes. These volumes will first need to be detached and reattached using the RESTAPI based driver. This is because we have changed the masking view architecture from Pike to better support this functionality.
  2. Consistency groups are deprecated in Pike. Generic Volume Groups are supported from Pike onwards.

SSL support

  1. Get the CA certificate of the Unisphere server. This pulls the CA cert file and saves it as .pem file:

    # openssl s_client -showcerts \
                   -connect my_unisphere_host:8443 </dev/null 2>/dev/null \
                   | openssl x509 -outform PEM > my_unisphere_host.pem

    Where my_unisphere_host is the hostname of the unisphere instance and my_unisphere_host.pem is the name of the .pem file.

  2. Add this path to the cinder.conf under the backend stanza

    driver_ssl_cert_path = /path/to/my_unisphere_host.pem

    OR follow the steps below:

  3. OPTIONAL (if step 2 completed): Copy the pem file to the system certificate directory:

    # cp my_unisphere_host.pem /usr/share/ca-certificates/ca_cert.crt

  4. OPTIONAL: Update CA certificate database with the following commands:

    # sudo dpkg-reconfigure ca-certificates

    Note

    Check that the new ca_cert.crt will activate by selecting ask on the dialog. If it is not enabled for activation, use the down and up keys to select, and the space key to enable or disable.

    # sudo update-ca-certificates

  5. Ensure driver_ssl_cert_verify is set to True in cinder.conf backend stanza OR the path defined in step 1.

Note

Issue

"Caused by SSLError(CertificateError("hostname 'xx.xx.xx.xx' doesn't match 'xx.xx.xx.xx'

Solution

  1. Check that requests and it's dependencies are up to date:

    $ sudo pip install requests --upgrade

  2. Verify the SSL cert was created using the command:

    $ openssl s_client -showcerts -connect {my_unisphere_host}:{port} </dev/null 2>/dev/null|openssl x509 -outform PEM >{cert_name}.pem

  3. Verify the cert using command:

    $ openssl s_client --connect {ip_address}:{port} -CAfile {cert_name}.pem -verify 9

  4. If requests is up to date and the cert is created correctly and verified but the hostname error still persists, install ipaddress to determine if it clears the hostname error:

    $ sudo pip install ipaddress

FC Zoning with VMAX

Zone Manager is required when there is a fabric between the host and array. This is necessary for larger configurations where pre-zoning would be too complex and open-zoning would raise security concerns.

iSCSI with VMAX

  • Make sure the iscsi-initiator-utils package is installed on all Compute nodes.

Note

You can only ping the VMAX iSCSI target ports when there is a valid masking view. An attach operation creates this masking view.

VMAX masking view and group naming info

Masking view names

Masking views are dynamically created by the VMAX FC and iSCSI drivers using the following naming conventions. [protocol] is either I for volumes attached over iSCSI or F for volumes attached over Fiber Channel.

OS-[shortHostName]-[protocol]-[portgroup_name]-MV

Initiator group names

For each host that is attached to VMAX volumes using the drivers, an initiator group is created or re-used (per attachment type). All initiators of the appropriate type known for that host are included in the group. At each new attach volume operation, the VMAX driver retrieves the initiators (either WWNNs or IQNs) from OpenStack and adds or updates the contents of the Initiator Group as required. Names are of the following format. [protocol] is either I for volumes attached over iSCSI or F for volumes attached over Fiber Channel.

OS-[shortHostName]-[protocol]-IG

Note

Hosts attaching to OpenStack managed VMAX storage cannot also attach to storage on the same VMAX that are not managed by OpenStack.

FA port groups

VMAX array FA ports to be used in a new masking view are retrieved from the port group provided as the extra spec on the volume type, or chosen from the list provided in the Dell EMC configuration file.

Storage group names

As volumes are attached to a host, they are either added to an existing storage group (if it exists) or a new storage group is created and the volume is then added. Storage groups contain volumes created from a pool, attached to a single host, over a single connection type (iSCSI or FC). [protocol] is either I for volumes attached over iSCSI or F for volumes attached over Fiber Channel. VMAX cinder driver utilizes cascaded storage groups -a parent storage group which is associated with the masking view, which contains child storage groups for each configured SRP/slo/workload/compression-enabled or disabled/replication-enabled or disabled combination.

VMAX All Flash and Hybrid

Parent storage group:

OS-[shortHostName]-[protocol]-[portgroup_name]-SG

Child storage groups:

OS-[shortHostName]-[SRP]-[ServiceLevel/Workload]-[portgroup_name]-CD-RE

Note

CD and RE are only set if compression is explicitly disabled or replication explicitly enabled. See the compression and replication sections below.

Interval and Retries

By default, interval and retries are 3 seconds and 200 retries respectively. These determine how long (interval) and how many times (retries) a user is willing to wait for a single Rest call, 3*200=600seconds. Depending on usage, these may need to be overridden by the user in the cinder.conf. For example, if performance is a factor, then the interval should be decreased to check the job status more frequently, and if multiple concurrent provisioning requests are issued then retries should be increased so calls will not timeout prematurely.

In the example below, the driver checks every 3 seconds for the status of the job. It will continue checking for 200 retries before it times out.

Add the following lines to the VMAX backend in the cinder.conf:

[CONF_GROUP_ISCSI]
volume_driver = cinder.volume.drivers.dell_emc.vmax.iscsi.VMAXISCSIDriver
volume_backend_name = VMAX_ISCSI_DIAMOND
vmax_port_groups = [OS-ISCSI-PG]
san_ip = 10.10.10.10
san_login = my_username
san_password = my_password
vmax_array = 000123456789
vmax_srp = SRP_1
interval = 3
retries = 200

QoS (Quality of Service) support

Quality of service (QoS) has traditionally been associated with network bandwidth usage. Network administrators set limitations on certain networks in terms of bandwidth usage for clients. This enables them to provide a tiered level of service based on cost. The Nova/cinder QoS offer similar functionality based on volume type setting limits on host storage bandwidth per service offering. Each volume type is tied to specific QoS attributes some of which are unique to each storage vendor. In the hypervisor, the QoS limits the following:

  • Limit by throughput - Total bytes/sec, read bytes/sec, write bytes/sec
  • Limit by IOPS - Total IOPS/sec, read IOPS/sec, write IOPS/sec

QoS enforcement in cinder is done either at the hypervisor (front end), the storage subsystem (back end), or both. This section focuses on QoS limits that are enforced by either the VMAX backend and the hypervisor front end interchangeably or just back end (Vendor Specific). The VMAX driver offers support for Total bytes/sec limit in throughput and Total IOPS/sec limit of IOPS.

The VMAX driver supports the following attributes that are front end/back end agnostic

  • total_iops_sec - Maximum IOPs (in I/Os per second). Valid values range from 100 IO/Sec to 100,000 IO/sec.
  • total_bytes_sec - Maximum bandwidth (throughput) in bytes per second. Valid values range from 1048576 bytes (1MB) to 104857600000 bytes (100, 000MB)

The VMAX driver offers the following attribute that is vendor specific to the VMAX and dependent on the total_iops_sec and/or total_bytes_sec being set.

  • Dynamic Distribution - Enables/Disables dynamic distribution of host I/O limits. Possible values are:
    • Always - Enables full dynamic distribution mode. When enabled, the configured host I/O limits will be dynamically distributed across the configured ports, thereby allowing the limits on each individual port to adjust to fluctuating demand.
    • OnFailure - Enables port failure capability. When enabled, the fraction of configured host I/O limits available to a configured port will adjust based on the number of ports currently online.
    • Never - Disables this feature (Default).

USE CASE 1 - Default values

Prerequisites - VMAX

  • Host I/O Limit (MB/Sec) - No Limit
  • Host I/O Limit (IO/Sec) - No Limit
  • Set Dynamic Distribution - N/A
Prerequisites - Block Storage (cinder) back end (storage group)
Key Value

total_iops_sec

500

total_bytes_sec

 104857600 (100MB)

DistributionType

 Always

  1. Create QoS Specs with the prerequisite values above:

    $ openstack volume qos create --consumer back-end \
                              --property total_iops_sec=500 \
                              --property total_bytes_sec=104857600 \
                              --property DistributionType=Always \
                              my_qos

  2. Associate QoS specs with specified volume type:

    $ openstack volume qos associate my_qos my_volume_type

  3. Create volume with the volume type indicated above:

    $ openstack volume create --size 1 --type my_volume_type my_volume

Outcome - VMAX (storage group)

  • Host I/O Limit (MB/Sec) - 100
  • Host I/O Limit (IO/Sec) - 500
  • Set Dynamic Distribution - Always

Outcome - Block Storage (cinder)

Volume is created against volume type and QoS is enforced with the parameters above.

USE CASE 2 - Preset limits

Prerequisites - VMAX

  • Host I/O Limit (MB/Sec) - 2000
  • Host I/O Limit (IO/Sec) - 2000
  • Set Dynamic Distribution - Never
Prerequisites - Block Storage (cinder) back end (storage group)
Key Value

total_iops_sec

 500

total_bytes_sec

 104857600 (100MB)

DistributionType

 Always

  1. Create QoS specifications with the prerequisite values above. The consumer in this case use case is both for front end and back end:

    $ openstack volume qos create --consumer back-end \
                              --property total_iops_sec=500 \
                              --property total_bytes_sec=104857600 \
                              --property DistributionType=Always \
                              my_qos

  2. Associate QoS specifications with specified volume type:

    $ openstack volume qos associate my_qos my_volume_type

  3. Create volume with the volume type indicated above:

    $ openstack volume create --size 1 --type my_volume_type my_volume

  4. Attach the volume created in step 3 to an instance

    $ openstack server add volume my_volume my_instance

Outcome - VMAX (storage group)

  • Host I/O Limit (MB/Sec) - 100
  • Host I/O Limit (IO/Sec) - 500
  • Set Dynamic Distribution - Always

Outcome - Block Storage (cinder)

Volume is created against volume type and QoS is enforced with the parameters above.

Outcome - Hypervisor (nova)

Libvirt includes an extra xml flag within the <disk> section called iotune that is responsible for rate limitation. To confirm that, first get the OS-EXT-SRV-ATTR:instance_name value of the server instance i.e. instance-00000003.

$ openstack server show <serverid>

+-------------------------------------+-----------------------------------------------------------------+
| Field                               | Value                                                           |
+-------------------------------------+-----------------------------------------------------------------+
| OS-DCF:diskConfig                   | AUTO                                                            |
| OS-EXT-AZ:availability_zone         | nova                                                            |
| OS-EXT-SRV-ATTR:host                | myhost                                                          |
| OS-EXT-SRV-ATTR:hypervisor_hostname | myhost                                                          |
| OS-EXT-SRV-ATTR:instance_name       | instance-00000003                                               |
| OS-EXT-STS:power_state              | Running                                                         |
| OS-EXT-STS:task_state               | None                                                            |
| OS-EXT-STS:vm_state                 | active                                                          |
| OS-SRV-USG:launched_at              | 2017-11-02T08:15:42.000000                                      |
| OS-SRV-USG:terminated_at            | None                                                            |
| accessIPv4                          |                                                                 |
| accessIPv6                          |                                                                 |
| addresses                           | private=fd21:99c2:73f3:0:f816:3eff:febe:30ed, 10.0.0.3          |
| config_drive                        |                                                                 |
| created                             | 2017-11-02T08:15:34Z                                            |
| flavor                              | m1.tiny (1)                                                     |
| hostId                              | e7b8312581f9fbb8508587d45c0b6fb4dc86102c632ed1f3a6a49d42        |
| id                                  | 0ef0ff4c-dbda-4dc7-b8ed-45d2fc2f31db                            |
| image                               | cirros-0.3.5-x86_64-disk (b7c220f5-2408-4296-9e58-fc5a41cb7e9d) |
| key_name                            | myhostname                                                      |
| name                                | myhosthame                                                      |
| progress                            | 0                                                               |
| project_id                          | bae4b97a0d8b42c28a5add483981e5db                                |
| properties                          |                                                                 |
| security_groups                     | name='default'                                                  |
| status                              | ACTIVE                                                          |
| updated                             | 2017-11-02T08:15:42Z                                            |
| user_id                             | 7bccf456740546799a7e20457f13c38b                                |
| volumes_attached                    |                                                                 |
+-------------------------------------+-----------------------------------------------------------------+

We then run the following command using the OS-EXT-SRV-ATTR:instance_name retrieved above.

$ virsh dumpxml instance-00000003 | grep -1 "total_bytes_sec\|total_iops_sec"

The output of the command contains the xml below. It is found between the <disk> start and end tag.

<iotune>
   <total_bytes_sec>104857600</total_bytes_sec>
   <total_iops_sec>500</total_iops_sec>
</iotune>

USE CASE 3 - Preset limits

Prerequisites - VMAX

  • Host I/O Limit (MB/Sec) - 100
  • Host I/O Limit (IO/Sec) - 500
  • Set Dynamic Distribution - Always
Prerequisites - Block Storage (cinder) back end (storage group)
Key Value

total_iops_sec

 500

total_bytes_sec

 104857600 (100MB)

DistributionType

 OnFailure

  1. Create QoS specifications with the prerequisite values above:

    $ openstack volume qos create --consumer back-end \
                              --property total_iops_sec=500 \
                              --property total_bytes_sec=104857600 \
                              --property DistributionType=Always \
                              my_qos

  2. Associate QoS specifications with specified volume type:

    $ openstack volume qos associate my_qos my_volume

  3. Create volume with the volume type indicated above:

    $ openstack volume create --size 1 --type my_volume_type my_volume

Outcome - VMAX (storage group)

  • Host I/O Limit (MB/Sec) - 100
  • Host I/O Limit (IO/Sec) - 500
  • Set Dynamic Distribution - OnFailure

Outcome - Block Storage (cinder)

Volume is created against volume type and QOS is enforced with the parameters above

USE CASE 4 - Default values

Prerequisites - VMAX

  • Host I/O Limit (MB/Sec) - No Limit
  • Host I/O Limit (IO/Sec) - No Limit
  • Set Dynamic Distribution - N/A
Prerequisites - Block Storage (cinder) back end (storage group)
Key Value

DistributionType

 Always

  1. Create QoS specifications with the prerequisite values above:

    $ openstack volume qos create --consumer back-end \
                              --property DistributionType=Always \
                              my_qos

  2. Associate QoS specifications with specified volume type:

    $ openstack volume qos associate my_qos my_volume_type

  3. Create volume with the volume type indicated above:

    $ openstack volume create --size 1 --type my_volume_type my_volume

Outcome - VMAX (storage group)

  • Host I/O Limit (MB/Sec) - No Limit
  • Host I/O Limit (IO/Sec) - No Limit
  • Set Dynamic Distribution - N/A

Outcome - Block Storage (cinder)

Volume is created against volume type and there is no QoS change.

iSCSI multipathing support

  • Install open-iscsi on all nodes on your system
  • Do not install EMC PowerPath as they cannot co-exist with native multipath software
  • Multipath tools must be installed on all nova compute nodes

On Ubuntu:

# apt-get install multipath-tools      #multipath modules
# apt-get install sysfsutils sg3-utils #file system utilities
# apt-get install scsitools            #SCSI tools

On openSUSE and SUSE Linux Enterprise Server:

# zipper install multipath-tools      #multipath modules
# zipper install sysfsutils sg3-utils #file system utilities
# zipper install scsitools            #SCSI tools

On Red Hat Enterprise Linux and CentOS:

# yum install iscsi-initiator-utils   #ensure iSCSI is installed
# yum install device-mapper-multipath #multipath modules
# yum install sysfsutils sg3-utils    #file system utilities

Multipath configuration file

The multipath configuration file may be edited for better management and performance. Log in as a privileged user and make the following changes to /etc/multipath.conf on the Compute (nova) node(s).

devices {
# Device attributed for EMC VMAX
    device {
            vendor "EMC"
            product "SYMMETRIX"
            path_grouping_policy multibus
            getuid_callout "/lib/udev/scsi_id --page=pre-spc3-83 --whitelisted --device=/dev/%n"
            path_selector "round-robin 0"
            path_checker tur
            features "0"
            hardware_handler "0"
            prio const
            rr_weight uniform
            no_path_retry 6
            rr_min_io 1000
            rr_min_io_rq 1
    }
}

You may need to reboot the host after installing the MPIO tools or restart iSCSI and multipath services.

On Ubuntu:

# service open-iscsi restart
# service multipath-tools restart

On openSUSE, SUSE Linux Enterprise Server, Red Hat Enterprise Linux, and CentOS:

# systemctl restart open-iscsi
# systemctl restart multipath-tools
$ lsblk
NAME                                       MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda                                          8:0    0     1G  0 disk
..360000970000196701868533030303235 (dm-6) 252:6    0     1G  0 mpath
sdb                                          8:16   0     1G  0 disk
..360000970000196701868533030303235 (dm-6) 252:6    0     1G  0 mpath
vda                                        253:0    0     1T  0 disk

OpenStack configurations

On Compute (nova) node, add the following flag in the [libvirt] section of /etc/nova/nova.conf and /etc/nova/nova-cpu.conf:

volume_use_multipath = True

On cinder controller node, iSCSI MPIO can be set globally in the [DEFAULT] section or set individually in the VMAX backend stanza in /etc/cinder/cinder.conf:

use_multipath_for_image_xfer = True

Restart nova-compute and cinder-volume services after the change.

Verify you have multiple initiators available on the compute node for I/O

  1. Create a 3GB VMAX volume.

  2. Create an instance from image out of native LVM storage or from VMAX storage, for example, from a bootable volume

  3. Attach the 3GB volume to the new instance:

    # multipath -ll
mpath102 (360000970000196700531533030383039) dm-3 EMC,SYMMETRIX
size=3G features='1 queue_if_no_path' hwhandler='0' wp=rw
'-+- policy='round-robin 0' prio=1 status=active
33:0:0:1 sdb 8:16 active ready running
'- 34:0:0:1 sdc 8:32 active ready running

  4. Use the lsblk command to see the multipath device:

    # lsblk
NAME                                       MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sdb                                          8:0    0     3G  0 disk
..360000970000196700531533030383039 (dm-6) 252:6    0     3G  0 mpath
sdc                                          8:16   0     3G  0 disk
..360000970000196700531533030383039 (dm-6) 252:6    0     3G  0 mpath
vda

CHAP Authentication Support

This supports one way initiator CHAP authentication functionality into the VMAX backend. With CHAP one-way authentication, the storage array challenges the host during the initial link negotiation process and expects to receive a valid credential and CHAP secret in response. When challenged, the host transmits a CHAP credential and CHAP secret to the storage array. The storage array looks for this credential and CHAP secret which stored in the host initiator's initiator group (IG) information in the ACLX database. Once a positive authentication occurs, the storage array sends an acceptance message to the host. However, if the storage array fails to find any record of the credential/secret pair, it sends a rejection message, and the link is closed.

Assumptions, Restrictions and Pre-Requisites

  1. The host initiator IQN is required along with the credentials the host initiator will use to log into the storage array with. The same credentials should be used in a multi node system if connecting to the same array.

  2. Enable one way CHAP authentication for the iscsi initiator on the storage array using SYMCLI. Template and example shown below. For the purpose of this setup, the credential/secret used would be my_username/my_password with iscsi initiator of iqn.1991-05.com.company.lcseb130

    # symaccess -sid <SymmID> -iscsi <iscsi>
            enable chap |
            disable chap |
            set chap -cred <Credential> -secret <Secret>

# symaccess -sid 128 \
            -iscsi iqn.1991-05.com.company.lcseb130 \
            set chap -cred my_username -secret my_password

Settings and Configuration

  1. Set the configuration in the VMAX backend group in cinder.conf using the following parameters and restart cinder.

    Configuration options Value required for CHAP Required for CHAP

    use_chap_auth

    		 True Yes

    chap_username

    		 my_username Yes

    chap_password

    		 my_password Yes 
    [VMAX_ISCSI_DIAMOND]
image_volume_cache_enabled = True
volume_clear = zero
volume_driver = cinder.volume.drivers.dell_emc.vmax.iscsi.VMAXISCSIDriver
volume_backend_name = VMAX_ISCSI_DIAMOND
san_ip = 10.10.10.10
san_login = my_u4v_username
san_password = my_u4v_password
vmax_srp = SRP_1
vmax_array = 000123456789
vmax_port_groups = [OS-ISCSI-PG]
use_chap_auth = True
chap_username = my_username
chap_password = my_password

Usage

  1. Using SYMCLI, enable CHAP authentication for a host initiator as described above, but do not set use_chap_auth, chap_username or chap_password in cinder.conf. Create a bootable volume.

    openstack volume create --size 1 \
                        --image <image_name> \
                        --type <volume_type> \
                        test

  2. Boot instance named test_server using the volume created above:

    openstack server create --volume test \
                        --flavor m1.small \
                        --nic net-id=private \
                        test_server

  3. Verify the volume operation succeeds but the boot instance fails as CHAP authentication fails.

  4. Update the cinder.conf with use_chap_auth set to true and chap_username and chap_password set with the correct credentials.

  5. Rerun openstack server create

  6. Verify that the boot instance operation ran correctly and the volume is accessible.

  7. Verify that both the volume and boot instance operations ran successfully and the user is able to access the volume.

All Flash compression support

On an All Flash array, the creation of any storage group has a compressed attribute by default. Setting compression on a storage group does not mean that all the devices will be immediately compressed. It means that for all incoming writes compression will be considered. Setting compression off on a storage group does not mean that all the devices will be uncompressed. It means all the writes to compressed tracks will make these tracks uncompressed.

Note

This feature is only applicable for All Flash arrays, 250F, 450F or 850F.

Use case 1 - Compression disabled create, attach, detach, and delete volume

  1. Create a new volume type called VMAX_COMPRESSION_DISABLED.
  2. Set an extra spec volume_backend_name.
  3. Set a new extra spec storagetype:disablecompression = True.
  4. Create a new volume.
  5. Check in Unisphere or symcli to see if the volume exists in storage group OS-<srp>-<servicelevel>-<workload>-CD-SG, and compression is disabled on that storage group.
  6. Attach the volume to an instance. Check in Unisphere or symcli to see if the volume exists in storage group OS-<shorthostname>-<srp>-<servicelevel/workload>-<portgroup>-CD, and compression is disabled on that storage group.
  7. Detach volume from instance. Check in Unisphere or symcli to see if the volume exists in storage group OS-<srp>-<servicelevel>-<workload>-CD-SG, and compression is disabled on that storage group.
  8. Delete the volume. If this was the last volume in the OS-<srp>-<servicelevel>-<workload>-CD-SG storage group, it should also be deleted.

Use case 2 - Retype from compression disabled to compression enabled

  1. Repeat steps 1-4 of Use case 1.
  2. Create a new volume type. For example VMAX_COMPRESSION_ENABLED.
  3. Set extra spec volume_backend_name as before.
  4. Set the new extra spec's compression as storagetype:disablecompression = False or DO NOT set this extra spec.
  5. Retype from volume type VMAX_COMPRESSION_DISABLED to VMAX_COMPRESSION_ENABLED.
  6. Check in Unisphere or symcli to see if the volume exists in storage group OS-<srp>-<servicelevel>-<workload>-SG, and compression is enabled on that storage group.

Note

If extra spec storagetype:disablecompression is set on a hybrid, it is ignored because compression is not a feature on a VMAX3 hybrid.

Volume replication support

Configure the source and target arrays

  1. Configure an SRDF group between the chosen source and target arrays for the VMAX cinder driver to use. The source array must correspond with the 'vmax_array' entry in the cinder.conf (or the <Array> entry in the VMAX XML file for legacy setups).

  2. Select both the director and the ports for the SRDF emulation to use on both sides. Bear in mind that network topology is important when choosing director endpoints. Supported modes are Synchronous, Asynchronous, and Metro.

    Note

    If the source and target arrays are not managed by the same Unisphere server (that is, the target array is remotely connected to server -for example, if you are using embedded management), in the event of a full disaster scenario (i.e. the primary array is completely lost and all connectivity to it is gone), the Unisphere server would no longer be able to contact the target array. In this scenario, the volumes would be automatically failed over to the target array, but administrator intervention would be required to either; configure the target (remote) array as local to the current Unisphere server (if it is a stand-alone server), or enter the details of a second Unisphere server to the cinder.conf, which is locally connected to the target array (for example, the embedded management Unisphere server of the target array), and restart the cinder volume service.

    Note

    If you are setting up an SRDF/Metro configuration, it is recommended that you configure a Witness or vWitness for bias management. Please see https://www.emc.com/collateral/technical-documentation/h14556-vmax3-srdf-metro-overview-and-best-practices-tech-note.pdf

  3. Enable replication in /etc/cinder/cinder.conf. To enable the replication functionality in VMAX cinder driver, it is necessary to create a replication volume-type. The corresponding back-end stanza in the cinder.conf for this volume-type must then include a replication_device parameter. This parameter defines a single replication target array and takes the form of a list of key value pairs.

    enabled_backends = VMAX_FC_REPLICATION
[VMAX_FC_REPLICATION]
volume_driver = cinder.volume.drivers.dell_emc.vmax_fc.VMAXFCDriver
san_ip = 10.10.10.10
san_login = my_u4v_username
san_password = my_u4v_password
vmax_srp = SRP_1
vmax_array = 000123456789
vmax_port_groups = [OS-FC-PG]
use_chap_auth = True
chap_username = my_username
chap_password = my_password
volume_backend_name = VMAX_FC_REPLICATION
replication_device = target_device_id:000197811111,
                     remote_port_group:os-failover-pg,
                     remote_pool:SRP_1,
                     rdf_group_label: 28_11_07,
                     allow_extend:False,
                     mode:Metro,
                     metro_use_bias:False,
                     allow_delete_metro:False

.. note::

   ``replication_device`` key value pairs will need to be on the same line
   (separated by commas) in cinder.conf.  They are displayed on separated lines
   above for readiblity.

    • target_device_id is a unique VMAX array serial number of the target array. For full failover functionality, the source and target VMAX arrays must be discovered and managed by the same U4V server.

    • remote_port_group is the name of a VMAX port group that has been pre-configured to expose volumes managed by this backend in the event of a failover. Make sure that this portgroup contains either all FC or all iSCSI port groups (for a given back end), as appropriate for the configured driver (iSCSI or FC).

    • remote_pool is the unique pool name for the given target array.

    • rdf_group_label is the name of a VMAX SRDF group that has been pre-configured between the source and target arrays.

    • allow_extend is a flag for allowing the extension of replicated volumes. To extend a volume in an SRDF relationship, this relationship must first be broken, both the source and target volumes are then independently extended, and then the replication relationship is re-established. If not explicitly set, this flag defaults to False.

      Note

      As the SRDF link must be severed, due caution should be exercised when performing this operation. If absolutely necessary, only one source and target pair should be extended at a time.

      Note

      It is not currently possible to extend SRDF/Metro protected volumes.

    • mode is the required replication mode. Options are 'Synchronous', 'Asynchronous', and 'Metro'. This defaults to 'Synchronous'.

    • metro_use_bias is a flag to indicate if 'bias' protection should be used instead of Witness. This defaults to False.

    • allow_delete_metro is a flag to indicate if metro devices can be deleted. All Metro devices in an RDF group need to be managed together, so in order to delete one of the pairings, the whole group needs to be first suspended. Because of this, we require this flag to be explicitly set. This flag defaults to False.

    Note

    Service Level and Workload: An attempt will be made to create a storage group on the target array with the same service level and workload combination as the primary. However, if this combination is unavailable on the target (for example, in a situation where the source array is a Hybrid, the target array is an All Flash, and an All Flash incompatible service level like Bronze is configured), no service level will be applied.

    Note

    The VMAX cinder drivers can support a single replication target per back-end, that is we do not support Concurrent SRDF or Cascaded SRDF. Ensure there is only a single replication_device entry per back-end stanza.

  4. Create a replication-enabled volume type. Once the replication_device parameter has been entered in the VMAX backend entry in the cinder.conf, a corresponding volume type needs to be created replication_enabled property set. See above Setup VMAX drivers for details.

    # openstack volume type set --property replication_enabled="<is> True" \
                      VMAX_FC_REPLICATION

Volume replication interoperability with other features

Most features are supported, except for the following:

  • Replication Group operations are available for volumes in Synchronous mode only.

  • Storage-assisted retype operations on replication-enabled VMAX volumes (moving from a non-replicated type to a replicated-type and vice-versa. Moving to another service level/workload combination, for example) are not supported.

  • It is not currently possible to extend SRDF/Metro protected volumes. If a bigger volume size is required for a SRDF/Metro protected volume, this can be achieved by cloning the original volume and choosing a larger size for the new cloned volume.

  • The image volume cache functionality is supported (enabled by setting image_volume_cache_enabled = True), but one of two actions must be taken when creating the cached volume:

    • The first boot volume created on a backend (which will trigger the cached volume to be created) should be the smallest necessary size. For example, if the minimum size disk to hold an image is 5GB, create the first boot volume as 5GB.
    • Alternatively, ensure that the allow_extend option in the replication_device parameter is set to True (Please note that it is not possible to extend SRDF/Metro protected volumes).

    This is because the initial boot volume is created at the minimum required size for the requested image, and then extended to the user specified size.

Failover host

In the event of a disaster, or where there is required downtime, upgrade of the primary array for example, the administrator can issue the failover host command to failover to the configured target:

# cinder failover-host cinder_host@VMAX_FC_REPLICATION

If the primary array becomes available again, you can initiate a failback using the same command and specifying --backend_id default:

# cinder failover-host cinder_host@VMAX_FC_REPLICATION --backend_id default

Note

Failover and Failback operations are not applicable in Metro configurations.

Asynchronous and Metro replication management groups

Asynchronous and Metro volumes in an RDF session, i.e. belonging to an SRDF group, must be managed together for RDF operations (although there is a consistency exempt option for creating and deleting pairs in an Async group). To facilitate this management, we create an internal RDF management storage group on the backend. It is crucial for correct management that the volumes in this storage group directly correspond to the volumes in the RDF group. For this reason, it is imperative that the RDF group specified in the cinder.conf is for the exclusive use by this cinder backend.

Metro support

SRDF/Metro is a High Availabilty solution. It works by masking both sides of the RDF relationship to the host, and presenting all paths to the host, appearing that they all point to the one device. In order to do this, there needs to be multipath software running to manage writing to the multiple paths.

Volume retype - storage assisted volume migration

Volume retype with storage assisted migration is supported now for VMAX3 arrays. Cinder requires that for storage assisted migration, a volume cannot be retyped across backends. For using storage assisted volume retype, follow these steps:

  1. For migrating a volume from one Service Level or Workload combination to another, use volume retype with the migration-policy to on-demand. The target volume type should have the same volume_backend_name configured and should have the desired pool_name to which you are trying to retype to (please refer to Setup VMAX Drivers for details).

    $ cinder retype --migration-policy on-demand <volume> <volume-type>

Generic volume group support

Generic volume group operations are performed through the CLI using API version 3.1x of the cinder API. Generic volume groups are multi-purpose groups which can be used for various features. The VMAX plugin supports consistent group snapshots and replication groups. Consistent group snapshots allows the user to take group snapshots which are consistent based on the group specs. Replication groups allow for/ tenant facing APIs to enable and disable replication, and to failover and failback, a group of volumes. Generic volume groups have replaced the deprecated consistency groups.

Consistent group snapshot

To create a consistent group snapshot, set a group-spec, having the key consistent_group_snapshot_enabled set to <is> True on the group.

cinder --os-volume-api-version 3.11 group-type-key GROUP_TYPE set consistent_group_snapshot_enabled="<is> True"

Similarly the same key should be set on any volume type which is specified while creating the group.

# openstack volume type set --property replication_enabled="<is> True" /
                        VMAX_REPLICATION

If this key is not set on the group-spec or volume type, then the generic volume group will be created/managed by cinder (not the VMAX plugin).

Note

The consistent group snapshot should not be confused with the VMAX consistency group which is an SRDF construct.

Replication groups

As with Consistent group snapshot consistent_group_snapshot_enabled should be set to true on the group and the volume type for replication groups. Only Synchronous replication is supported for use with Replication Groups. When a volume is created into a replication group, replication is on by default. The disable_replication api suspends I/O traffic on the devices, but does NOT remove replication for the group. The enable_replication api resumes I/O traffic on the RDF links. The "failover_group" api allows a group to be failed over and back without failing over the entire host. See below for usage.

Note

A generic volume group can be both consistent group snapshot enabled and consistent group replication enabled.

Storage Group Names

Storage groups are created on the VMAX as a result of creation of generic volume groups. These storage groups follow a different naming convention and are of the following format depending upon whether the groups have a name.

TruncatedGroupName_GroupUUID or GroupUUID

Group type operations

  • Create a group type
cinder --os-volume-api-version 3.11 group-type-create GROUP_TYPE
  • Show a group type
cinder --os-volume-api-version 3.11 group-type-show GROUP_TYPE
  • List group types
cinder --os-volume-api-version 3.11 group-type-list
  • Delete group type
cinder --os-volume-api-version 3.11 group-type-delete GROUP_TYPE
  • Set/unset a group spec
cinder --os-volume-api-version 3.11 group-type-key GROUP_TYPE set consistent_group_snapshot_enabled="<is> True"
  • List group types and group specs:
cinder --os-volume-api-version 3.11 group-specs-list

Group operations

  • Create a group:
cinder --os-volume-api-version 3.13 group-create --name GROUP GROUP_TYPE VOLUME_TYPE1,VOLUME_TYPE2
  • Show a group:
cinder --os-volume-api-version 3.13 group-show GROUP
  • List all groups:
cinder --os-volume-api-version 3.13 group-list
  • Create a volume and add it to a group at the time of creation:
cinder --os-volume-api-version 3.13 create --volume-type VOLUME_TYPE1 --group-id GROUP_ID 1
  • Modify a group to add or remove volumes:
cinder --os-volume-api-version 3.13 group-update --add-volumes UUID1,UUID2 --remove-volumes UUID3,UUID4 GROUP
  • Delete a group
cinder --os-volume-api-version 3.13 group-delete --delete-volumes GROUP

Group snapshot operations

  • Create a group snapshot:
cinder --os-volume-api-version 3.14 group-snapshot-create --name GROUP_SNAPSHOT GROUP
  • Delete group snapshot(s):
cinder --os-volume-api-version 3.14 group-snapshot-delete GROUP_SNAPSHOT
  • Create a group from a group snapshot:
$ cinder --os-volume-api-version 3.14 group-create-from-src --group-snapshot GROUP_SNAPSHOT --name GROUP
  • Create a group from a source snapshot:
$ cinder --os-volume-api-version 3.14 group-create-from-src --source-group SOURCE_GROUP --name GROUP

Group replication operations

  • Enable group replication
cinder --os-volume-api-version 3.38 group-enable-replication GROUP
  • Disable group replication
cinder --os-volume-api-version 3.38 group-disable-replication GROUP
  • Failover group
cinder --os-volume-api-version 3.38 group-failover-replication GROUP
  • Failback group
cinder --os-volume-api-version 3.38 group-failover-replication GROUP /
    --secondary-backend-id default

Oversubscription support

Please refer to the following: https://docs.openstack.org/cinder/latest/admin/blockstorage-over-subscription.html

Live Migration support

Non-live migration (sometimes referred to simply as 'migration'). The instance is shut down for a period of time to be moved to another hypervisor. In this case, the instance recognizes that it was rebooted. Live migration (or 'true live migration'). Almost no instance downtime. Useful when the instances must be kept running during the migration. The different types of live migration are:

  • Shared storage-based live migration. Both hypervisors have access to shared storage.
  • Block live migration. No shared storage is required. Incompatible with read-only devices such as CD-ROMs and Configuration Drive (config_drive).
  • Volume-backed live migration. Instances are backed by volumes rather than ephemeral disk. For VMAX volume-backed live migration, shared storage is required.

The VMAX driver supports shared volume-backed live migration.

Architecture

In VMAX, A volume cannot belong to two or more FAST storage groups at the same time. To get around this limitation we leverage both cascaded storage groups and a temporary non FAST storage group.

A volume can remain 'live' if moved between masking views that have the same initiator group and port groups which preserves the host path.

During live migration, the following steps are performed by the VMAX plugin on the volume:

  1. Within the originating masking view, the volume is moved from the FAST storage group to the non-FAST storage group within the parent storage group.
  2. The volume is added to the FAST storage group within the destination parent storage group of the destination masking view. At this point the volume belongs to two storage groups.
  3. One of two things happens:
    • If the connection to the destination instance is successful, the volume is removed from the non-FAST storage group in the originating masking view, deleting the storage group if it contains no other volumes.
    • If the connection to the destination instance fails, the volume is removed from the destination storage group, deleting the storage group, if empty. The volume is reverted back to the original storage group.

Libvirt configuration

Make the following updates on all nodes, controller and compute nodes, that are involved in live migration. Update the libvirt configurations. Please refer to following link for further information: http://libvirt.org/remote.html

  1. Update the libvirt configurations. Modify the /etc/libvirt/libvirtd.conf file

    before : #listen_tls = 0
after : listen_tls = 0

before : #listen_tcp = 1
after : listen_tcp = 1
add: auth_tcp = "none"

  2. Modify the /etc/libvirt/qemu.conf file:

    before : #dynamic_ownership = 1
after : dynamic_ownership = 0
before : #security_driver = "selinux"
after : security_driver = "none"
before : #user = "root"
after : user = "root"
before : #group = "root"
after : group = "root"

  3. Modify the /etc/default/libvirtd file:

    before: libvirtd_opts=" -d"
after: libvirtd_opts=" -d -l"

  4. Restart libvirt. After you run the command below, ensure that libvirt is successfully restarted:

Note

OpenStack Oslo uses an open standard for messaging middleware known as AMQP. This messaging middleware (the RPC messaging system) enables the OpenStack services that run on multiple servers to talk to each other. By default, the RPC messaging client is set to timeout after 60 seconds, meaning if any operation you perform takes longer than 60 seconds to complete the operation will timeout and fail with the ERROR message "Messaging Timeout: Timed out waiting for a reply to message ID [message_id]"

If this occurs, increase the rpc_response_timeout flag value in cinder.conf and nova.conf on all Cinder and Nova nodes and restart the services.

What to change this value to will depend entirely on your own environment, you might only need to increase it slightly, or if your environment is under heavy network load it could need a bit more time than normal. Fine tuning is required here, change the value and run intensive operations to determine if your timeout value matches your environment requirements.

At a minimum please set rpc_response_timeout to 240, but this will need to be raised if high concurrency is a factor. This should be sufficient for all cinder backup commands also.

System configuration

NOVA-INST-DIR/instances/ (for example, /opt/stack/data/nova/instances) has to be mounted by shared storage. Ensure that NOVA-INST-DIR (set with state_path in the nova.conf file) is the same on all hosts.

  1. Configure your DNS or /etc/hosts and ensure it is consistent across all hosts. Make sure that the three hosts can perform name resolution with each other. As a test, use the ping command to ping each host from one another.

    $ ping HostA
$ ping HostB
$ ping HostC

  2. Export NOVA-INST-DIR/instances from HostA, and ensure it is readable and writable by the Compute user on HostB and HostC. Please refer to the relevant OS documentation for further details. e.g. https://help.ubuntu.com/lts/serverguide/network-file-system.html

  3. On all compute nodes, enable the 'execute/search' bit on your shared directory to allow qemu to be able to use the images within the directories. On all hosts, run the following command:

    $ chmod o+x NOVA-INST-DIR/instances

Note

If migrating from compute to controller, make sure to run step two above on the controller node to export the instance directory.

Use case

For our use case shown below, we have three hosts with host names HostA, HostB and HostC. HostA is the compute node while HostB and HostC are the compute nodes. The following were also used in live migration.

  • 2 gb bootable volume using the cirros image.
  • Instance created using the 2gb volume above with a flavor m1.small using 2048 RAM, 20GB of Disk and 1 VCPU.

  1. Create a bootable volume.

    $ openstack volume create --size 2 \
                          --image cirros-0.3.5-x86_64-disk \
                          --volume_lm_1

  2. Launch an instance using the volume created above on HostB.

    $ openstack server create --volume volume_lm_1 \
                          --flavor m1.small \
                          --nic net-id=private \
                          --security-group default \
                          --availability-zone nova:HostB \
                          server_lm_1

  3. Confirm on HostB has the instance created by running:

    $ openstack server show server_lm_1 | grep "hypervisor_hostname\|instance_name"
  | OS-EXT-SRV-ATTR:hypervisor_hostname | HostB
  | OS-EXT-SRV-ATTR:instance_name | instance-00000006

  4. Confirm, through virsh using the instance_name returned in step 3 (instance-00000006), on HostB that the instance is created using:

    $ virsh list --all

Id   Name                  State
--------------------------------
1    instance-00000006     Running

  5. Migrate the instance from HostB to HostA with:

    $ openstack server migrate --live HostA \
                           server_lm_1

  6. Run the command on step 3 above when the instance is back in available status. The hypervisor should be on Host A.

  7. Run the command on Step 4 on Host A to confirm that the instance is created through virsh.

Manage and Unmanage Volumes

Managing volumes in OpenStack is the process whereby a volume which exists on the storage device is imported into OpenStack to be made available for use in the OpenStack environment. For a volume to be valid for managing into OpenStack, the following prerequisites must be met:

  • The volume exists in a Cinder managed pool
  • The volume is not part of a Masking View
  • The volume is not part of an SRDF relationship
  • The volume is configured as a TDEV (thin device)
  • The volume is set to FBA emulation
  • The volume must a whole GB e.g. 5.5GB is not a valid size
  • The volume cannot be a snapvx target

For a volume to exist in a Cinder managed pool, it must reside in in the same Storage Resource Pool (SRP) as the backend which is configured for use in OpenStack. Specifying the pool correctly can be entered manually as it follows the same format:

Pool format: <service_level>+<workload_type>+<srp>+<array_id>
Pool example 1: Diamond+DSS+SRP_1+111111111111
Pool example 2: Diamond+SRP_1+111111111111
Pool values
Key Value

service_level

 The service level of the volume to be managed

workload

 The workload of the volume to be managed

SRP

 The Storage Resource Pool configured for use by the backend

array_id

 The VMAX serial number (12 digit numerical)

Manage Volumes

With your pool name defined you can now manage the volume into OpenStack, this is possible with the CLI command cinder manage. The bootable parameter is optional in the command, if the volume to be managed into OpenStack is not bootable leave this parameter out. OpenStack will also determine the size of the value when it is managed so there is no need to specify the volume size.

Command format:

$ cinder manage --name <new_volume_name> --volume-type <vmax_vol_type> \
  --availability-zone <av_zone> <--bootable> <host> <identifier>

Command Example:

$ cinder manage --name vmax_managed_volume --volume-type VMAX_ISCSI_DIAMOND \
  --availability-zone nova demo@VMAX_ISCSI_DIAMOND#Diamond+SRP_1+111111111111 031D8

After the above command has been run, the volume will be available for use in the same way as any other OpenStack VMAX volume.

Note

An unmanaged volume with a prefix of 'OS-' in its identifier name cannot be managed into OpenStack, as this is a reserved keyword for managed volumes. If the identifier name has this prefix, an exception will be thrown by the VMAX driver on a manage operation.

Managing Volumes with Replication Enabled

Whilst it is not possible to manage volumes into OpenStack that are part of a SRDF relationship, it is possible to manage a volume into OpenStack and enable replication at the same time. This is done by having a replication enabled VMAX volume type (for more information see section Volume Replication) during the manage volume process you specify the replication volume type as the chosen volume type. Once managed, replication will be enabled for that volume.

Unmanage Volume

Unmanaging a volume is not the same as deleting a volume. When a volume is deleted from OpenStack, it is also deleted from the VMAX at the same time. Unmanaging a volume is the process whereby a volume is removed from OpenStack but it remains for further use on the VMAX. The volume can also be managed back into OpenStack at a later date using the process discussed in the previous section. Unmanaging volume is carried out using the Cinder unmanage CLI command:

Command format:

$ cinder unmanage <volume_name/volume_id>

Command example:

$ cinder unmanage vmax_test_vol

Once unmanaged from OpenStack, the volume can still be retrieved using its device ID or OpenStack volume ID. Within Unisphere you will also notice that the 'OS-' prefix has been removed, this is another visual indication that the volume is no longer managed by OpenStack.

Manage/Unmanage Snapshots

Users can manage VMAX SnapVX snapshots into OpenStack if the source volume already exists in Cinder. Similarly, users will be able to unmanage OpenStack snapshots to remove them from Cinder but keep them on the storage backend.

Set-up, restrictions and requirements:

  1. No additional settings or configuration is required to support this functionality.
  2. Manage/Unmanage snapshots requires SnapVX functionality support on VMAX.
  3. Manage/Unmanage Snapshots in OpenStack Cinder is only supported at present through Cinder CLI commands.
  4. It is only possible to manage or unmanage one snapshot at a time in Cinder.

Manage SnapVX Snapshot

It is possible to manage VMAX SnapVX snapshots into OpenStack, where the source volume from which the snapshot is taken already exists in, and is managed by OpenStack Cinder. The source volume may have been created in OpenStack Cinder, or it may have been managed in to OpenStack Cinder also. With the support of managing SnapVX snapshots included in OpenStack Queens, the restriction around managing SnapVX source volumes has been removed.

Note

It is not possible to manage into OpenStack SnapVX linked target volumes, or volumes which exist in a replication session.

Requirements/Restrictions:

  1. The SnapVX source volume must be present in and managed by Cinder.
  2. The SnapVX snapshot name must not begin with OS-.
  3. The SnapVX snapshot source volume must not be in a failed-over state.
  4. Managing a SnapVX snapshot will only be allowed if the snapshot has no linked target volumes.

Command Structure:

  1. Identify your SnapVX snapshot for management on the VMAX, note the name.
  2. Ensure the source volume is already managed into OpenStack Cinder, note the device ID.
  3. Using the Cinder CLI, use the following command structure to manage a Snapshot into OpenStack Cinder:
$ cinder snapshot-manage --id-type source-name
                         [--name <name>]
                         [--description <description>]
                         [--metadata [<key=value> [<key=value> ...]]]
                         <device_id> <identifier>

Positional arguments:

  • <device_id> - the VMAX device id
  • <identifier> - Name of existing snapshot

Optional arguments:

  • --name <name> - Snapshot name (Default=None)
  • --description <description> - Snapshot description (Default=None)
  • --metadata [<key=value> [<key=value> ...]] Metadata key=value pairs (Default=None)

Example:

$ cinder snapshot-manage --name SnapshotManaged \
                         --description "Managed Queens Feb18" \
                         0021A VMAXSnapshot

Where:

  • The name in OpenStack after managing the SnapVX snapshot will be SnapshotManaged.
  • The snapshot will have the description Managed Queens Feb18.
  • The source volume device ID is 0021A.
  • The name of the SnapVX snapshot on the VMAX backend is VMAXSnapshot.

Outcome:

After the process of managing the Snapshot has completed, the SnapVX snapshot on the VMAX backend will be prefixed by the letters OS-, leaving the snapshot in this example named OS-VMAXSnapshot. The associated snapshot managed by Cinder will be present for use under the name SnapshotManaged.

Unmanage Cinder Snapshot

Unmanaging a snapshot in Cinder is the process whereby the snapshot is removed from and no longer managed by Cinder, but it still exists on the storage backend. Unmanaging a SnapVX snapshot in OpenStack Cinder follows this behaviour, whereby after unmanaging a VMAX SnapVX snapshot from Cinder, the snapshot is removed from OpenStack but is still present for use on the VMAX backend.

Requirements/Restrictions:

  • The SnapVX source volume must not be in a failed over state.

Command Structure:

Identify the SnapVX snapshot you want to unmanage from OpenStack cinder, note the snapshot name or ID as specified by Cinder. Using the Cinder CLI use the following command structure to unmanage the SnapVX snapshot from Cinder:

$ cinder snapshot-unmanage <snapshot>

Positional arguments:

  • <snapshot> - Cinder snapshot name or ID.

Example:

$ cinder snapshot-unmanage SnapshotManaged

Where:

  • The SnapVX snapshot name in OpenStack Cinder is SnapshotManaged.

After the process of unmanaging the SnapVX snapshot in Cinder, the snapshot on the VMAX backend will have the OS- prefix removed to indicate it is no longer OpenStack managed. In the example above, the snapshot after unmanaging from OpenStack will be named VMAXSnapshot on the storage backend.