openstack/fuel-specs
Code Issues Proposed changes
2e7d6b2855
fuel-specs/specs/6.1/cinder-vmdk-role.rst
Andrey Danin 13c3f63e04 Add a blueprint about cinder-vmdk-role 
"Add a separate role for Cinder with VMDK backend" blueprint.

Blueprint: cinder-vmdk-role
Change-Id: I380ef956ee9618eda16412bd550c142e78443afa
2015-01-27 18:43:21 +03:00

7.2 KiB
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Add a separate role for Cinder with VMDK backend

https://blueprints.launchpad.net/fuel/+spec/cinder-vmdk-role

When vCenter is used as a hypervisor it can use volumes only from Cinder VMDK. And vise versa: KVM as a hypervisor cannot mount volumes from Cinder VMDK. In case of Multi-HV support with both vCenter and KVM Compute nodes deployed, it's necessary to deploy Cinder with multiple backends - VMDK plus LVM/Ceph. A new role "Cinder with VMDK" should be introduced to provide this opportunity.

Problem description

As it was said before, there is no universal Block Storage solution for both vCenter and KVM hypervisors in Fuel out-of-box. Storage types for different hypervisors:

  • For KVM, it's Cinder with LVM or Ceph backend
  • For vCenter, it's Cinder with VMDK backend

Fuel can not deploy cinder with LVM or Ceph backend and with VMDK backend simultaneously only one backend for the whole environment. It happens because Fuel 6.0 uses the only 'Cinder' role to deploy both backend types. An actual backend type is selected in Puppet depending on hypervisor type. Such workflow contradicts with the main Fuel idea - keep as more business logic in Nailgun as we can. Also, the only 'Cinder' role makes it hard to deploy VMDK and LVM/Ceph backends in one environment simultaneously.

I want to cover the following use case within blueprint [5]

Be able to deploy Cinder VMDK backend simultaneously with any other Cinder backends.

Proposed change

Introduce a new node role called 'cinder-vmware'. The role will deploy Cinder with VMDK backend. A Puppet code should be slightly refactored to use 'node[role]' value instead of 'libvirt_type==vcenter' to deploy Cinder VMDK backend.

An old role 'cinder' should keep deploying Cinder with LVM or Ceph. For clarification sake, it can be also renamed to 'cinder-qemu'.

The following should be done:

  • Remove the 'VMware vCenter for volumes (Cinder)' option from the UI wizard and the Settings tab of the Fuel web UI. Keep 'Default (LVM)' and 'Ceph' only.
  • vCenter settings for Cinder should be always available on the VMware Tab of the Fuel web UI.
  • The new role should always be available if vCenter instance was added to environment so that it can be shared with any other role.
  • It's allowed to deploy more than one node with the 'cinder-vmware' role.
  • It's not necessary to use Pacemaker for that Cinder service. HA will be achieved by deploying multiple Cinder instances with the same 'hostname' stanza and vCenter settings in cinder.conf.
  • For provide possibilities combine cinder-vmware and cinder-qemu roles on the same node cinder-vmware role should use different name for config file. cinder-vmware.conf will be good choise.
  • Nailgun should validate parameters before starting deployment to ensure that all the necessary vCenter credentials are provided.

Alternatives

There are no vital alternatives from my point of view.

Data model impact

None.

REST API impact

None.

Upgrade impact

No special upgrade impact. The new role will be provided with a new release. A Nailgun part should take proper account of release version and disable itself for old releases. Puppet manifests are located in different directories for different Fuel versions.

Security impact

None.

Notifications impact

Two more notifications will be added into the Fuel web UI.

  1. In "Deployed Changes" window: if there is one or more vCenter instance added and cinder VMDK backend is enabled , but no Cinder VMDK roles. The message should be the following: "In order to use volumes with vCenter instances, please add at least one 'Cinder with VMDK' role."
  2. In "Deployed Changes" window: if there is an HA environment but the only node with "Cinder with VMDK" role is provided. The message should be the following: "To provide HA for Cinder with VMDK backend, please select the 'Cinder with VMDK' role for at least two nodes."

One error message will be added.

  1. If the role 'cinder-vmware' is used for environment but vCenter credentials for Cinder incomplete or has wrong format, Nailgun should fail 'CheckBeforeDeploymentTask' task with the message: "The following errors happend: <list of errors>"

Other end user impact

The new role should be presented on UI. It can be combined with any other role.

Performance Impact

A little more network bandwith will be consumed.

Other deployer impact

None

Developer impact

Part of fuel-library, which deploys cinder-node will be reverted to state before support of vmdk was enabled. New role deployment will be realized as an independent task for granular deployment according to [4].

Implementation

Assignee(s)

Primary assignee:

Igor Gajsin - igajsin

Core reviewers:

Sergii Golovatiuk - sgolovatiuk

Other contributors:

UI part: Anton Zemlyanov - azemlyanov Nailgun part: Andriy Popovych - popovych-andrey QA section: Oleksandr Kosse - okosse, Tanya Dubyk - tdubyk

Work Items

There are three nearly independent parts of implementation:

  1. Append to Fuel new role and notifications. Provide possibilities for separate configuration of cinder and cinder-vmware nodes.
  2. Change puppet manifests for create and configure new role. Clean old class from parameters of vmdk.
  3. Create or modify the corresponding system and OSTF tests.

Dependencies

No strict dependencies.

Possible dependencies are:

  • Granular deployment feature [1].
  • VMware: Dual hypervisor support (vCenter and KVM in one environment) [2].
  • VMware UI Settings Tab for FuelWeb [3].

Testing

Our system tests are already good enough covers use-case of using cinder. But this tests depend on ostf tests, which know nothing about availability zones. Therefore OSTF tests can't test how cinder works in multiple availability zones environment. And surely tests, which based on OSTF, are also useless.

This problem will be fixed in blueprint [3]. When it happens, system tests should be changed for using with availability zones.

Before it the QA team may perform manual testing of declared features.

Documentation Impact

There are several changes in Users' Guide: #. Change the corresponding screenshots. #. Add description of new role.

References

[1] Granular deployment feature

(https://blueprints.launchpad.net/fuel/+spec/granular-deployment-based-on-tasks)

[2] VMware: Dual hypervisor support (vCenter and KVM in one environment)

(https://blueprints.launchpad.net/fuel/+spec/vmware-dual-hypervisor)

[3] VMware UI Settings Tab for FuelWeb

(https://blueprints.launchpad.net/fuel/+spec/vmware-ui-setting)

[4] Modify Fuel Library to become more modular

(https://blueprints.launchpad.net/fuel/+spec/fuel-library-modularization)

[5] VMware: Add a separate role for Cinder with VMDK backend

(https://blueprints.launchpad.net/fuel/+spec/cinder-vmdk-role)