Parallels Cloud Server support in nova/libvirt driver

Parallels Cloud Server support in nova/libvirt driver

https://blueprints.launchpad.net/nova/+spec/pcs-support

This specification is intended to describe process of extending nova/libvirt driver in order to support Parallels Cloud Server 1

Problem description

Parallels Cloud Server (PCS) is a virtualization solution product, which enables service providers to use container and hypervisor virtualization technology via the same management tools and API. Though PCS is supported by libvirt it is absent in OpenStack for now due to not only specific demand related to compute node deployment but also different disk image format implied by usage of Parallels disk loopback block device 2, domains configuration and supported features.

Use Cases

This change will allow those service providers that use PCS as their primary virtualization solution to build a cloud upon it using OpenStack. There is no impact on users who aren’t engaged with PCS.

Project Priority

No priority defined for this feature yet.

Proposed change

To make PCS be supported by OpenStack we need to modify nova/libvirt driver mostly regarding a new type of virtualization processing. The end user will be able to configure nova to use PCS by setting libvirt.virt_type option to “parallels”. Also, as a native disk format for both VMs and containers supported in PCS is ploop 2, to get best performance we will need to change glance-api configuration to support PCS ploop format. Using images of different formats will be provided by in-place convertion. As each host reports supported instances via the resource tracker and the ‘vm_mode’ property of images is used to determine what kind of virtualization to run an a particular host, a decision about it will be made on an image with particular vm_mode property (eg vm_mode=exe to run containers or vm_mode=hvm to run hypervisor based instances). So PCS hosts will support arbitrary mix of machine and container based guests. In case a cloud administrator needs a way to partition hosts into groups so that some hosts exclusively run machine virt, while other hosts exclusively run container virt, host aggregates and flavors extra specs should be used.

nova.conf extract example: [libvirt] … virt_type = parallels images_type = ploop …

glance-api.conf extract example: … disk_formats=ami,ari,aki,vhd,vmdk,raw,qcow2,vdi,iso,ploop …

Here is a list of of features we plan to support:

VMs

Containers

Launch

yes

yes

Reboot

yes

yes

Terminate

yes

yes

Resize

yes

yes

Rescue

yes

yes

Pause

yes

Un-pause

yes

Suspend

yes

yes

Resume

yes

yes

Inject Networking

yes

yes

Inject File

yes

yes

Serial Console Output

yes

no

VNC Console

yes

yes

SPICE Console

no

no

RDP Console

no

no

Attach Volume

yes

Detach Volume

yes

Live Migration

yes

yes

Snapshot

yes

yes

iSCSI

yes

yes

iSCSI CHAP

yes

yes

Fibre Channel

yes

yes

Set Admin Pass

yes

yes

Get Guest Info

yes

yes

Glance Integration

yes

yes

Service Control

no

yes

VLAN Networking

yes

yes

Flat Networking

yes

yes

Security Groups

yes

yes

Firewall Rules

yes

yes

nova diagnostics

no

no

Config Drive

yes

yes

Auto configure disk

no

yes

Evacuate

yes

yes

Volume swap

yes

Volume rate limiting

  1. There are no technical problems with pausing containers it’s not implemented by now.

  2. It’s possible to attach volume to a container either as a block device or as a mount point, giving both types of access simultaneously has a security problem.

  3. We can tune swap size in containers with vswap technology 4, not as a conventional swap disk.

  4. We can tune IO rate only for the whole instance but not for individual volumes.

Alternatives

The alternate way is to implement a separate PCS nova driver like this 3, which was implemented in terms of PCS + OpenStack proof of concept.

pros: * There is no middle layer between OpenStack and PCS as pcs-nova-driver uses native PCS’s python API. * Changes in pcs-nova-driver will not affect nova/libvirt’s code.

cons: * Yet another nova driver * It is out-of-tree driver

Data model impact

None.

REST API impact

None.

Security impact

None.

Notifications impact

None.

Other end user impact

None.

Performance Impact

None.

Other deployer impact

Compute nodes available for “parallels” type of virtualization have to be deployed in advance. Integrating PCS hosts deployment with OpenStack is out of this spec scope.

Developer impact

None.

Implementation

Assignee(s)

Primary assignee:

dguryanov

Other contributors:

burluka mnestratov

Work Items

  • Enhance libvirt driver to support new virt_type value.

  • Implement all the functionality necessary to support PCS in libvirt driver

Dependencies

Add support of new disk image format in glance Bluesprint https://blueprints.launchpad.net/glance/+spec/pcs-support

None

Testing

Testing in the gate will be provided by currently being established Parallels CI testing system.

Documentation Impact

New type of virtualization provider should be noticed and host deployment pre-requisites such as the need to have PCS installed on compute nodes.

References

1

Parallels Cloud Server http://www.parallels.com/products/pcs

2(1,2)

Ploop block device http://openvz.org/Ploop

3

PCS nova driver https://github.com/parallels/pcs-nova-driver

4

OpenVZ kernel memory management model https://openvz.org/VSwap

Creative Commons Attribution 3.0 License

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nova-specs