tacker-specs/specs/pike/persistent-block-storage.rst

Support persistent block storage in Tacker TOSCA

Include the URL of your launchpad blueprint:

https://blueprints.launchpad.net/tacker/+spec/persistent-block-storage

This spec is to describe a TOSCA template for Cinder volume, and map the new TOSCA attributes to Heat's Cinder volume.

Problem description

Currently Tacker doesn't have many storage related attributes exposed in its TOSCA template. VDU disk_size is probably the only thing. We don't have support for attaching a persistent virtual storage (like Cinder volume) to Tacker VDU. Sometimes, VDU also needs 'boot from volume' feature.

Background technology

Now in TOSCA template, it supports creating VDU only with volume size, not supports booting from volume and specifying whether to delete the created volumesif the VDU is deleted.

Heat introduction

Heat now supports block storage. The usage is below:

1. Create a new block storage volume

resources:
  my_new_volume:
    type: OS::Cinder::Volume
    properties:
      size: 10

2. Create a bootable volume from an existing image

resources:
  my_new_bootable_volume:
    type: OS::Cinder::Volume
    properties:
      size: 10
      image: ubuntu-trusty-x86_64

3. Create new volumes from another existing volume

resources:
  another_volume:
    type: OS::Cinder::Volume
    properties:
      source_volid: 2fff50ab-1a9c-4d45-ae60-1d054d6bc868

4. Create a new volume from another existing volume snapshot

resources:
  another_volume:
    type: OS::Cinder::Volume
    properties:
      snapshot_id: 2fff50ab-1a9c-4d45-ae60-1d054d6bc868

5. Create a new volume from another existing volume backup

resources:
  another_volume:
    type: OS::Cinder::Volume
    properties:
      backup_id: 2fff50ab-1a9c-4d45-ae60-1d054d6bc868

6. Create a new volume, and create an instance with this volume attached

resources:
  new_volume:
    type: OS::Cinder::Volume
    properties:
      size: 1

  new_instance:
    type: OS::Nova::Server
    properties:
      flavor: m1.small
      image: ubuntu-trusty-x86_64

  volume_attachment:
    type: OS::Cinder::VolumeAttachment
    properties:
      volume_id: { get_resource: new_volume }
      instance_uuid: { get_resource: new_instance }

7. Boot an instance from a volume and specify whether to delete the volume when the instance is deleted

resources:
  bootable_volume:
    type: OS::Cinder::Volume
    properties:
      size: 10
      image: ubuntu-trusty-x86_64

  instance:
    type: OS::Nova::Server
    properties:
      flavor: m1.small
      networks:
        - network: private
      block_device_mapping:
        - device_name: vda
          volume_id: { get_resource: bootable_volume }
          delete_on_termination: false

Proposed change

1. Attaching a volume in TOSCA template In this case, the instance boot from an image, with a new created volume attached.

We introduce two new nodes, named VB and CB. VB defines a block storage, while CB describes the relationship between VDU and VB. VB will be deleted when the VDU is removed. One TOSCA template can support multiple VBs and CBs.

topology_template:
  node_templates:
    VDU1:
      type: tosca.nodes.nfv.VDU.Tacker
      properties:
        image: centos
        flavor: centos

    CP1:
      type: tosca.nodes.nfv.CP.Tacker
      requirements:
        - virtualLink:
            node: VL1
        - virtualBinding:
            node: VDU1

    VL1:
      type: tosca.nodes.nfv.VL

    VB1:
      type: tosca.nodes.BlockStorage
      properties:
        size: 10 GB

    CB1:
      type: tosca.nodes.BlockStorageAttachment
      properties:
        location: /dev/vdb
      requirements:
        - virtualBinding:
            node: VDU1
        - virtualAttachment:
            node: VB1

2. TOSCA for boot from volume In this case, the instance boot from a volume. The volume can be created from many different material, e.g. from a image.

Same with 1, we introduce a node named VB to define a block storage. In the requirement section of VDU node, we use local_storage to define the boot volume. 'delete_on_termination' can be configured to determine whether to delete the volume when VDU deleting.

topology_template:
  node_templates:
    VDU1:
      type: tosca.nodes.nfv.VDU.Tacker
      properties:
        flavor: centos
      requirements:
        - local_storage:
            node: VB1
            relationship:
              type: tosca.relationships.AttachesTo
              location: /dev/vdb
              delete_on_termination: false

    CP1:
      type: tosca.nodes.nfv.CP.Tacker
      requirements:
        - virtualLink:
            node: VL1
        - virtualBinding:
            node: VDU1

    VL1:
      type: tosca.nodes.nfv.VL

    VB1:
      type: tosca.nodes.BlockStorage
      properties:
        size: 10 GB
        image: ubuntu-trusty-x86_64

3. VDU scaling scenario A volume can only be attached to one instance in current nova/cinder realization. In tacker vnf scaling scenario, a VDU may have many instantiated instances. So in heat, we need create multiple volumes for each instances. Unfortunately, heat does not support it.

So we should verify the tosca template have no scaling policies when block storage exists.

Alternatives

None

REST API impact

None

Security impact

None

Notifications impact

None

Other end user impact

None

Performance Impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

Zhou Zhihong<zhouzhihong@cmss.chinamobile.com>

Other contributors:

Yan Xing an<yanxingan@cmss.chinamobile.com>

Work Items

1. Add tosca template samples for block storage
2. Add codes to translate tosca template to HOT
3. UT testcase
4. FT testcase
5. devref doc

Dependencies

None

Testing

None

Documentation Impact

None

References

• http://docs.oasis-open.org/tosca/TOSCA-Simple-Profile-YAML/v1.0/csprd01/TOSCA-Simple-Profile-YAML-v1.0-csprd01.html#_Toc430015836