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== Summary == | == Summary == | ||
Enable [[Virtualization|VM hosts]] to discover new SAN storage | Enable [[Virtualization|VM hosts]] to discover new SAN storage and issue NPIV operations. | ||
== Owner == | == Owner == | ||
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* Targeted release: [[Releases/12|Fedora 12]] | * Targeted release: [[Releases/12|Fedora 12]] | ||
* Last updated: 2009- | * Last updated: 2009-08-05 | ||
* Percentage of completion: | * Percentage of completion: 100% | ||
== Detailed Description == | == Detailed Description == | ||
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=== Background === | === Background === | ||
Guest virtual machines can currently use SAN storage | Guest virtual machines can currently use SAN storage, but | ||
administrators must do the storage configuration manually using | |||
separate tools from libvirt. This feature will permit administrators | |||
to discover storage and present it to virtual machines using libvirt. | |||
using libvirt. | |||
Datacenter operations are usually split along functional lines: the | Datacenter operations are usually split along functional lines: the | ||
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While libvirt is currently capable of using SAN storage, it lacks the | While libvirt is currently capable of using SAN storage, it lacks the | ||
ability to trigger scans for new storage | ability to trigger scans for new storage and create virtual host | ||
using NPIV | adapters using NPIV. The OS admin team that manages the VM host must | ||
manages the VM host must get involved to get the VM host to recognize | get involved to get the VM host to recognize the new storage. Giving | ||
the new storage. Giving libvirt the ability to manage storage allows | libvirt the ability to manage storage allows the OS admin team | ||
the OS admin team responsible for the guest OS to complete the VM | responsible for the guest OS to complete the VM build out itself. | ||
build out itself. | |||
=== Implementation === | === Implementation === | ||
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The libvirt APIs already permit storage discovery and pool creation. | The libvirt APIs already permit storage discovery and pool creation. | ||
These functions will be extended to discover and rescan storage on a | These functions will be extended to discover and rescan storage on a | ||
per-SCSI-host basis | per-SCSI-host basis. The node device APIs will be extended to create | ||
APIs will be extended to create and destroy vitrual adapters using | and destroy vitrual adapters using NPIV. | ||
NPIV. | |||
== Benefit to Fedora == | == Benefit to Fedora == | ||
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=== TODO === | === TODO === | ||
=== Completed === | === Completed === | ||
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Provision a new logical unit on iSCSI or fibre channel storage. Use virsh to trigger a scan for it, and confirm that it appears correctly. | Provision a new logical unit on iSCSI or fibre channel storage. Use virsh to trigger a scan for it, and confirm that it appears correctly. | ||
To discover logical units on a particular HBA, create a pool for that | |||
HBA using: | |||
<code>virsh pool-create hbapool.xml</code> | |||
where hbapool.xml contains: | |||
<pre> | |||
<pool type="scsi"> | |||
<name>host6</name> | |||
<source> | |||
<adapter name="host6"/> | |||
</source> | |||
<target> | |||
<path>/dev/disk/by-id</path> | |||
</target> | |||
</pool> | |||
</pre> | |||
Confirm that all the appropriate logical units are visible as volumes | |||
with: | |||
<code>virsh vol-list host6</code> | |||
=== Create a virtual HBA with NPIV === | After creating the pool, add a new logical unit on a target that's | ||
visible on that host and refresh the pool with: | |||
<code>virsh pool-refresh host6</code> | |||
and confirm that the new storage is visible. Note that the refresh | |||
code only scans for new LUs on existing targets and does not issue a | |||
LIP to discover new targets as that would be disruptive to I/O. | |||
=== Create and destroy a virtual HBA with NPIV === | |||
Issue an NPIV create call and confirm that the VM host has instantiated a new host adapter and that any storage zoned to it is usable. | Issue an NPIV create call and confirm that the VM host has instantiated a new host adapter and that any storage zoned to it is usable. | ||
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kernel version you have. On recent kernels it's in: | kernel version you have. On recent kernels it's in: | ||
/sys/class/fc_host/hostN | <code>/sys/class/fc_host/hostN</code> | ||
on older kernels it's in: | on older kernels it's in: | ||
/sys/class/scsi_host/hostN | <code>/sys/class/scsi_host/hostN</code> | ||
Note also that the example WWN given below is bogus. If you try to | Note also that the example WWN given below is bogus. If you try to | ||
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For example on a recent kernel: | For example on a recent kernel: | ||
echo '1111222233334444:5555666677778888' > /sys/class/fc_host/host5/vport_create | <code>echo '1111222233334444:5555666677778888' > /sys/class/fc_host/host5/vport_create</code> | ||
where '1111222233334444:5555666677778888' is the WWPN:WWNN and host5 | where '1111222233334444:5555666677778888' is the WWPN:WWNN and host5 | ||
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You can then destroy the test virtual HBA with: | You can then destroy the test virtual HBA with: | ||
echo '1111222233334444:5555666677778888' > /sys/class/fc_host/host5/vport_delete | <code>echo '1111222233334444:5555666677778888' > /sys/class/fc_host/host5/vport_delete</code> | ||
Testing the libvirt API | Testing the libvirt API | ||
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your system with: | your system with: | ||
virsh nodedev-list --cap=scsi_host | <code>virsh nodedev-list --cap=scsi_host</code> | ||
For example: | For example: | ||
< | <pre> | ||
# virsh nodedev-list --cap=scsi_host | # virsh nodedev-list --cap=scsi_host | ||
pci_10df_fe00_0_scsi_host | pci_10df_fe00_0_scsi_host | ||
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pci_10df_fe00_scsi_host_0_scsi_host | pci_10df_fe00_scsi_host_0_scsi_host | ||
pci_10df_fe00_scsi_host_0_scsi_host_0 | pci_10df_fe00_scsi_host_0_scsi_host_0 | ||
</ | </pre> | ||
Dump the XML for each HBA until you find the host number of the | Dump the XML for each HBA until you find the host number of the | ||
physical HBA you want to use: | physical HBA you want to use: | ||
< | <pre> | ||
# virsh nodedev-dumpxml pci_10df_fe00_scsi_host | # virsh nodedev-dumpxml pci_10df_fe00_scsi_host | ||
<device> | <device> | ||
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</capability> | </capability> | ||
</device> | </device> | ||
< | </pre> | ||
HBAs that are capable of creating virtual adapters will have a | HBAs that are capable of creating virtual adapters will have a | ||
capability type='vport_ops'. | capability type='vport_ops'. | ||
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containing XML describing the virtual HBA you want to create: | containing XML describing the virtual HBA you want to create: | ||
<pre> | |||
<device> | <device> | ||
<parent>pci_10df_fe00_0_scsi_host</parent> | <parent>pci_10df_fe00_0_scsi_host</parent> | ||
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</capability> | </capability> | ||
</device> | </device> | ||
</pre> | |||
The parent element is the name of the parent HBA as listed by virsh | The parent element is the name of the parent HBA as listed by virsh | ||
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somewhat misleading, however: | somewhat misleading, however: | ||
<pre> | |||
# virsh nodedev-create badwwn.xml | # virsh nodedev-create badwwn.xml | ||
error: Failed to create node device from badwwn.xml | error: Failed to create node device from badwwn.xml | ||
error: Write of '1111222233334444:5555666677778888' to '/sys/class/fc_host/host6/vport_create' during vport create/delete failed: No such file or directory | error: Write of '1111222233334444:5555666677778888' to '/sys/class/fc_host/host6/vport_create' during vport create/delete failed: No such file or directory | ||
</pre> | |||
To create the new virtual HBA, feed the file to virsh: | To create the new virtual HBA, feed the file to virsh: | ||
virsh nodedev-create new.xml | <code>virsh nodedev-create new.xml</code> | ||
If the operation succeeds, you'll get a message similar to: | If the operation succeeds, you'll get a message similar to: | ||
<pre> | |||
# virsh nodedev-create dpa/newhost.xml | # virsh nodedev-create dpa/newhost.xml | ||
Node device pci_10df_fe00_0_scsi_host_0_scsi_host created from new.xml | Node device pci_10df_fe00_0_scsi_host_0_scsi_host created from new.xml | ||
</pre> | |||
and you will see the new HBA in the OS. The create command output | and you will see the new HBA in the OS. The create command output | ||
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To destroy the device, use virsh nodedev-destroy: | To destroy the device, use virsh nodedev-destroy: | ||
<pre> | |||
# virsh nodedev-destroy pci_10df_fe00_0_scsi_host_0_scsi_host | # virsh nodedev-destroy pci_10df_fe00_0_scsi_host_0_scsi_host | ||
Destroyed node device 'pci_10df_fe00_0_scsi_host_0_scsi_host' | Destroyed node device 'pci_10df_fe00_0_scsi_host_0_scsi_host' | ||
</pre> | |||
and you will see the HBA disappear from the OS. | and you will see the HBA disappear from the OS. | ||
== User Experience == | == User Experience == | ||
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== Release Notes == | == Release Notes == | ||
This functionality adds the ability in libvirt to discover storage on a per-SCSI-host basis | This functionality adds the ability in libvirt to discover storage on a per-SCSI-host basis and issue NPIV operations. This enables administrators to discover, configure and provision storage for virtual machines without having to use multiple tools. | ||
== Comments and Discussion == | == Comments and Discussion == | ||
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[[Category:Virtualization|Virtualized Storage Management]] | [[Category:Virtualization|Virtualized Storage Management]] | ||
[[Category:F12 Virt Features|Virtualized Storage Management]] | [[Category:F12 Virt Features|Virtualized Storage Management]] | ||
[[Category: | [[Category:FeatureAcceptedF12]] |
Latest revision as of 18:10, 5 August 2009
Summary
Enable VM hosts to discover new SAN storage and issue NPIV operations.
Owner
- Name: Dave Allan
- Email: dallan at redhat dot com
Current status
- Targeted release: Fedora 12
- Last updated: 2009-08-05
- Percentage of completion: 100%
Detailed Description
Background
Guest virtual machines can currently use SAN storage, but administrators must do the storage configuration manually using separate tools from libvirt. This feature will permit administrators to discover storage and present it to virtual machines using libvirt.
Datacenter operations are usually split along functional lines: the server administration team, the SAN administration team, and others (network, etc.) not relevant to this discussion. Within the server admin group, there are often sub-groups for each OS. When a new application is deployed the SAN admins provision the storage and notify whichever OS team is responsible for the server to proceed with the OS install.
There may be more or less information transmitted from the SAN admins to the server admins when the storage becomes available. The minimal message is something along the lines of, "I've provisioned the LUNs, and you should be able to see them now. The LUNs are 27, 28, 29 and 53." The server admin may not know what targets or hosts the new storage is accessible through, but a rescan of all host adapters will show up new logical units of the size requested with numbers 27, 28, 29 and 53 on some target on some host, and the server admin assumes, usually reasonably, that these logical units are the new storage.
While libvirt is currently capable of using SAN storage, it lacks the ability to trigger scans for new storage and create virtual host adapters using NPIV. The OS admin team that manages the VM host must get involved to get the VM host to recognize the new storage. Giving libvirt the ability to manage storage allows the OS admin team responsible for the guest OS to complete the VM build out itself.
Implementation
The libvirt APIs already permit storage discovery and pool creation. These functions will be extended to discover and rescan storage on a per-SCSI-host basis. The node device APIs will be extended to create and destroy vitrual adapters using NPIV.
Benefit to Fedora
Administrators will be able to provision storage for VMs from the single set of tools that they are already using to manage the VMs.
Scope
As described above, changes are required in libvirt. Eventually the tools using libvirt will need to be updated to take advantage of the new features, but that is not within the scope of this work.
TODO
Completed
- SCSI storage discovery and rescan are complete.
- The creation and destruction of virtual HBAs using NPIV is complete.
How To Test
Use cases
Discover SAN storage
Provision a new logical unit on iSCSI or fibre channel storage. Use virsh to trigger a scan for it, and confirm that it appears correctly.
To discover logical units on a particular HBA, create a pool for that HBA using:
virsh pool-create hbapool.xml
where hbapool.xml contains:
<pool type="scsi"> <name>host6</name> <source> <adapter name="host6"/> </source> <target> <path>/dev/disk/by-id</path> </target> </pool>
Confirm that all the appropriate logical units are visible as volumes with:
virsh vol-list host6
After creating the pool, add a new logical unit on a target that's visible on that host and refresh the pool with:
virsh pool-refresh host6
and confirm that the new storage is visible. Note that the refresh code only scans for new LUs on existing targets and does not issue a LIP to discover new targets as that would be disruptive to I/O.
Create and destroy a virtual HBA with NPIV
Issue an NPIV create call and confirm that the VM host has instantiated a new host adapter and that any storage zoned to it is usable.
To create virtual HBAs using libvirt, it is of course necessary to have an NPIV capable HBA and switch. You can confirm that you have those by manually creating a new HBA by an echo into sysfs.
The file you echo into may be in one of two places, depending on which kernel version you have. On recent kernels it's in:
/sys/class/fc_host/hostN
on older kernels it's in:
/sys/class/scsi_host/hostN
Note also that the example WWN given below is bogus. If you try to use it, the kernel will reject it. You should pick a WWN that makes sense for your SAN.
For example on a recent kernel:
echo '1111222233334444:5555666677778888' > /sys/class/fc_host/host5/vport_create
where '1111222233334444:5555666677778888' is the WWPN:WWNN and host5 is the physical HBA you want to use to create the virtual HBA. If the create is successful, you'll get a new HBA in the system with the next available host number.
You can then destroy the test virtual HBA with:
echo '1111222233334444:5555666677778888' > /sys/class/fc_host/host5/vport_delete
Testing the libvirt API
The libvirt API implementation is intended to be used by client applications, but the functionality can be tested with virsh.
Creating a new virtual adapter using virsh is a two step process. First, find the node device name of the HBA that's going to be used to create the virtual adapter. You can get a list of all the HBAs on your system with:
virsh nodedev-list --cap=scsi_host
For example:
# virsh nodedev-list --cap=scsi_host pci_10df_fe00_0_scsi_host pci_10df_fe00_0_scsi_host_0 pci_10df_fe00_scsi_host pci_10df_fe00_scsi_host_0 pci_10df_fe00_scsi_host_0_scsi_host pci_10df_fe00_scsi_host_0_scsi_host_0
Dump the XML for each HBA until you find the host number of the physical HBA you want to use:
# virsh nodedev-dumpxml pci_10df_fe00_scsi_host <device> <name>pci_10df_fe00_scsi_host</name> <parent>pci_10df_fe00</parent> <capability type='scsi_host'> <host>5</host> <capability type='fc_host'> <wwnn>20000000c9848140</wwnn> <wwpn>10000000c9848140</wwpn> </capability> <capability type='vport_ops' /> </capability> </device>
HBAs that are capable of creating virtual adapters will have a capability type='vport_ops'.
Once you know the node device name of the parent HBA, create a file containing XML describing the virtual HBA you want to create:
<device> <parent>pci_10df_fe00_0_scsi_host</parent> <capability type='scsi_host'> <capability type='fc_host'> <wwpn>1111222233334444</wwpn> <wwnn>5555666677778888</wwnn> </capability> </capability> </device>
The parent element is the name of the parent HBA as listed by virsh nodedev-list. wwpn and wwnn are, as you would expect, the WWNN and WWPN for the virtual HBA to be created. Libvirt does not do any validation of the WWPN/WWNN; invalid WWNs are rejected by the kernel and libvirt reports the failure. The error reported by the kernel is somewhat misleading, however:
# virsh nodedev-create badwwn.xml error: Failed to create node device from badwwn.xml error: Write of '1111222233334444:5555666677778888' to '/sys/class/fc_host/host6/vport_create' during vport create/delete failed: No such file or directory
To create the new virtual HBA, feed the file to virsh:
virsh nodedev-create new.xml
If the operation succeeds, you'll get a message similar to:
# virsh nodedev-create dpa/newhost.xml Node device pci_10df_fe00_0_scsi_host_0_scsi_host created from new.xml
and you will see the new HBA in the OS. The create command output gives you the node device name of the newly created device.
To destroy the device, use virsh nodedev-destroy:
# virsh nodedev-destroy pci_10df_fe00_0_scsi_host_0_scsi_host Destroyed node device 'pci_10df_fe00_0_scsi_host_0_scsi_host'
and you will see the HBA disappear from the OS.
User Experience
See the previous section.
Dependencies
None, outside of the implementation efforts detailed above.
Contingency Plan
This functionality is independent of all other features. If it is not ready, administrators can continue to configure storage manually.
Documentation
Release Notes
This functionality adds the ability in libvirt to discover storage on a per-SCSI-host basis and issue NPIV operations. This enables administrators to discover, configure and provision storage for virtual machines without having to use multiple tools.