
Adds storage-assisted migration support for Unity driver. Change-Id: Ibaf2e6a09f93b167b6b1477d5653922d807fccce Implements: blueprint unity-storage-assisted-volume-migration-support
13 KiB
Dell EMC Unity driver
Unity driver has been integrated in the OpenStack Block Storage project since the Ocata release. The driver is built on the top of Block Storage framework and a Dell EMC distributed Python package storops.
Prerequisites
Software | Version |
---|---|
Unity OE | 4.1.X or newer |
storops | 0.5.10 or newer |
Supported operations
- Create, delete, attach, and detach volumes.
- Create, delete, attach, and detach compressed volumes.
- Create, list, and delete volume snapshots.
- Create a volume from a snapshot.
- Copy an image to a volume.
- Create an image from a volume.
- Clone a volume.
- Extend a volume.
- Migrate a volume.
- Get volume statistics.
- Efficient non-disruptive volume backup.
- Revert a volume to a snapshot.
- Create thick volumes.
- Attach a volume to multiple servers simultaneously (multiattach).
Driver configuration
Note
The following instructions should all be performed on Black Storage nodes.
Install storops from pypi:
# pip install storops
Add the following content into
/etc/cinder/cinder.conf
:[DEFAULT] enabled_backends = unity [unity] # Storage protocol storage_protocol = iSCSI # Unisphere IP san_ip = <SAN IP> # Unisphere username and password san_login = <SAN LOGIN> san_password = <SAN PASSWORD> # Volume driver name volume_driver = cinder.volume.drivers.dell_emc.unity.Driver # backend's name volume_backend_name = Storage_ISCSI_01
Note
These are minimal options for Unity driver, for more options, see Driver options.
Note
(Optional) If you require multipath based data access, perform below steps on both Block Storage and Compute nodes.
Install
sysfsutils
,sg3-utils
andmultipath-tools
:# apt-get install multipath-tools sg3-utils sysfsutils
(Required for FC driver in case Auto-zoning Support is disabled) Zone the FC ports of Compute nodes with Unity FC target ports.
Enable Unity storage optimized multipath configuration:
Add the following content into
/etc/multipath.conf
blacklist { # Skip the files uner /dev that are definitely not FC/iSCSI devices # Different system may need different customization devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*" devnode "^hd[a-z][0-9]*" devnode "^cciss!c[0-9]d[0-9]*[p[0-9]*]" # Skip LUNZ device from VNX/Unity device { vendor "DGC" product "LUNZ" } } defaults { user_friendly_names no flush_on_last_del yes } devices { # Device attributed for EMC CLARiiON and VNX/Unity series ALUA device { vendor "DGC" product ".*" product_blacklist "LUNZ" path_grouping_policy group_by_prio path_selector "round-robin 0" path_checker emc_clariion features "0" no_path_retry 12 hardware_handler "1 alua" prio alua failback immediate } }
Restart the multipath service:
# service multipath-tools restart
Enable multipath for image transfer in
/etc/cinder/cinder.conf
.use_multipath_for_image_xfer = True
Restart the
cinder-volume
service to load the change.Enable multipath for volume attache/detach in
/etc/nova/nova.conf
.[libvirt] ... volume_use_multipath = True ...
Restart the
nova-compute
service.
Driver options
cinder.volume.drivers.dell_emc.unity.driver
FC or iSCSI ports option
Specify the list of FC or iSCSI ports to be used to perform the IO. Wild card character is supported. For iSCSI ports, use the following format:
unity_io_ports = spa_eth2, spb_eth2, *_eth3
For FC ports, use the following format:
unity_io_ports = spa_iom_0_fc0, spb_iom_0_fc0, *_iom_0_fc1
List the port ID with the uemcli
command:
$ uemcli /net/port/eth show -output csv
...
"spa_eth2","SP A Ethernet Port 2","spa","file, net, iscsi", ...
"spb_eth2","SP B Ethernet Port 2","spb","file, net, iscsi", ...
...
$ uemcli /net/port/fc show -output csv
...
"spa_iom_0_fc0","SP A I/O Module 0 FC Port 0","spa", ...
"spb_iom_0_fc0","SP B I/O Module 0 FC Port 0","spb", ...
...
Live migration integration
It is suggested to have multipath configured on Compute nodes for
robust data access in VM instances live migration scenario. Once
user_friendly_names no
is set in defaults section of
/etc/multipath.conf
, Compute nodes will use the WWID as the
alias for the multipath devices.
To enable multipath in live migration:
Note
Make sure Driver configuration steps are performed before following steps.
Set multipath in
/etc/nova/nova.conf
:[libvirt] ... volume_use_multipath = True ...
Restart nova-compute service.
Set
user_friendly_names no
in/etc/multipath.conf
... defaults { user_friendly_names no } ...
Restart the
multipath-tools
service.
Thin and thick provisioning
By default, the volume created by Unity driver is thin provisioned. Run the following commands to create a thick volume.
# openstack volume type create --property provisioning:type=thick \
--property thick_provisioning_support='<is> True' thick_volume_type
# openstack volume create --type thick_volume_type thick_volume
Compressed volume support
Unity driver supports compressed volume
creation,
modification and deletion. In order to create a compressed volume, a
volume type which enables compression support needs to be created
first:
$ openstack volume type create CompressedVolumeType
$ openstack volume type set --property provisioning:type=compressed --property compression_support='<is> True' CompressedVolumeType
Then create volume and specify the new created volume type.
Storage-assisted volume migration support
Unity driver supports storage-assisted volume migration, when the
user starts migrating with
cinder migrate --force-host-copy False <volume_id> <host>
or cinder migrate <volume_id> <host>
, cinder
will try to leverage the Unity's native volume migration functionality.
If Unity fails to migrate the volume, host-assisted migration will be
triggered.
In the following scenarios, Unity storage-assisted volume migration will not be triggered. Instead, host-assisted volume migration will be triggered:
- Volume is to be migrated across backends.
- Migration of cloned volume. For example, if vol_2 was cloned from vol_1, the storage-assisted volume migration of vol_2 will not be triggered.
QoS support
Unity driver supports maxBWS
and maxIOPS
specs for the back-end consumer type. maxBWS
represents the
Maximum IO/S
absolute limit, maxIOPS
represents the Maximum Bandwidth (KBPS)
absolute limit on
the Unity respectively.
Auto-zoning support
Unity volume driver supports auto-zoning, and share the same
configuration guide for other vendors. Refer to fc_zone_manager
for detailed
configuration steps.
Solution for LUNZ device
The EMC host team also found LUNZ on all of the hosts, EMC best practice is to present a LUN with HLU 0 to clear any LUNZ devices as they can cause issues on the host. See KB LUNZ Device.
To workaround this issue, Unity driver creates a Dummy LUN (if not present), and adds it to each host to occupy the HLU 0 during volume attachment.
Note
This Dummy LUN is shared among all hosts connected to the Unity.
Efficient non-disruptive volume backup
The default implementation in Block Storage for non-disruptive volume backup is not efficient since a cloned volume will be created during backup.
An effective approach to backups is to create a snapshot for the volume and connect this snapshot to the Block Storage host for volume backup.
SSL support
Admin is able to enable the SSL verification for any communication against Unity REST API.
By default, the SSL verification is disabled, user can enable it by following steps:
- Setup the Unity array certificate and import it to the Unity, see section Storage system certificate of Security Configuration Guide.
- Import the CA certficate to the Cinder nodes on which the driver is running.
- Enable the changes on cinder nodes and restart the cinder services.
[unity]
...
driver_ssl_cert_verify = True
driver_ssl_cert_path = <path to the CA>
...
If driver_ssl_cert_path is omitted, the system default CA will be used for CA verification.
IPv6 support
This driver can support IPv6-based control path and data path.
For control path, please follow below steps:
- Enable Unity's Unipshere IPv6 address.
- Configure the IPv6 network to make sure that cinder node can access Unishpere via IPv6 address.
- Change Cinder config file
/etc/cinder/cinder.conf
. Make thesan_ip
as Unisphere IPv6 address. For example,san_ip = [fd99:f17b:37d0::100]
. - Restart the Cinder service to make new configuration take effect.
Note: The IPv6 support on control path depends on the fix of cpython bug 32185. Please make sure your Python's version includes this bug's fix.
For data path, please follow below steps:
- On Unity, Create iSCSI interface with IPv6 address.
- Configure the IPv6 network to make sure that you can
ping
the Unity's iSCSI IPv6 address from the Cinder node. - If you create a volume using Cinder and attach it to a VM, the connection between this VM and volume will be IPv6-based iSCSI.
Force detach volume from all hosts
The user could use os-force_detach action to detach a volume from all its attached hosts. For more detail, please refer to https://developer.openstack.org/api-ref/block-storage/v2/?expanded=force-detach-volume-detail#force-detach-volume
Troubleshooting
To troubleshoot a failure in OpenStack deployment, the best way is to enable verbose and debug log, at the same time, leverage the build-in Return request ID to caller to track specific Block Storage command logs.
Enable verbose log, set following in
/etc/cinder/cinder.conf
and restart all Block Storage services:[DEFAULT] ... debug = True verbose = True ...
If other projects (usually Compute) are also involved, set debug and
verbose
toTrue
.use
--debug
to trigger any problematic Block Storage operation:# cinder --debug create --name unity_vol1 100
You will see the request ID from the console, for example:
DEBUG:keystoneauth:REQ: curl -g -i -X POST http://192.168.1.9:8776/v2/e50d22bdb5a34078a8bfe7be89324078/volumes -H "User-Agent: python-cinderclient" -H "Content-Type: application/json" -H "Accept: application/json" -H "X-Auth-Token: {SHA1}bf4a85ad64302b67a39ad7c6f695a9630f39ab0e" -d '{"volume": {"status": "creating", "user_id": null, "name": "unity_vol1", "imageRef": null, "availability_zone": null, "description": null, "multiattach": false, "attach_status": "detached", "volume_type": null, "metadata": {}, "consistencygroup_id": null, "source_volid": null, "snapshot_id": null, "project_id": null, "source_replica": null, "size": 10}}' DEBUG:keystoneauth:RESP: [202] X-Compute-Request-Id: req-3a459e0e-871a-49f9-9796-b63cc48b5015 Content-Type: application/json Content-Length: 804 X-Openstack-Request-Id: req-3a459e0e-871a-49f9-9796-b63cc48b5015 Date: Mon, 12 Dec 2016 09:31:44 GMT Connection: keep-alive
Use commands like
grep
,awk
to find the error related to the Block Storage operations.# grep "req-3a459e0e-871a-49f9-9796-b63cc48b5015" cinder-volume.log