Support VNF update operations on changing VNF instances with MgmtDriver

Blueprint URL: https://blueprints.launchpad.net/tacker/+spec/container-update

This specification describes VNF Modify Information operation for configuration support in case of Container update.

Problem description

VNF update API in ETSI NFV-SOL003 v2.6.1 [1] supports updating VNFD itself in the current Tacker implementation support-vnf-update-api-based-on-etsi-nfv-sol, but there is no way to reflect configuration changes to VNF instances. Currently there is no preamble or postamble supported in the MgmtDriver for the Modify VNF operation, so we will support configuration changes to VNF instances by adding preamble and postamble to MgmtDriver. There are many use cases for Modify VNF operations, but this specification focuses on changing the configuration of ConfigMap and Secret in Kubernetes and changing the image parameters in the Pod and Deployment manifests.

Proposed change

We would propose the following changes:

1. Implement preamble and postamble for modify VNF operation.

   • VnfLcmDriver supports modify_start and modify_end to invoke the process provided by MgmtDriver scripts, which is created and included in VNF packages by users. Refer to mgmt_driver_deploy_k8s_usage_guide for how to use MgmtDriver.

   Note

   modify_start has no action for this use case.

2. Provide Updated manifest file to perform the following operations:

   • Update Kubernetes ConfigMap and Secret.

   • Recreate Kubernetes Pod.

   Note

   The image parameter is the only modifiable parameter in the manifest file for a Pod or Deployment. Changing parameters other than image is not supported because they may be inconsistent with information managed by Tacker.

3. Modify VNF operation performs the following operations:

   • The attributes in the TackerDB to be updated are as follows:

     • VnfInstance.vnfdId: Replace the existing vnfd ID with the new vnfd ID.

     • VnfInstance.instantiatedVnfInfo.vnfcResourceInfo.computeResource.resourceId: Update resourceId with the new resource ID because the resource ID changes after the Pod is recreated.

Note

In the current implementation, this vnfd_id parameter is updated in conductor_server. We will move this update process of vnfd_id from conductor_server to VnfLcmDriver.

Note

The operation flow of the modify VNF is shown below:

1. Onboard and instantiate the original VNF package.

2. Onboard the new VNF package and modify the existing VNF instance.

Because of the above procedure, the old VNF package and the new VNF package coexist. The old VNF package must be deleted by the user after modify VNF operation.

Design of operation

Below is a diagram of the VNF Modify Information operation:

                                       +---------------+ +--------+
                                       | Updated       | |  VNFD  |
                                       | manifest file | |        |
                                       +-------------+-+ +-+------+
                                                     |     |
                                                     v     v
                                                   +----------+  +------------------+
                                                   |   CSAR   |  | Modify Request   |
                                                   |          |  | with new vnfd_id |
                                                   +----+-----+  +-+----------------+
                                                        |          | 1. Modify VNF Information request
                                                        |          |
                                                  +-----+----------+--------------------------------------+
                                                  |     v          v        VNFM                          |
                                                  |  +------------------------------+                     |
                                                  |  |   Tacker-server              |                     |
                                                  |  +--+---------------------------+                     |
                                                  |     |  2. Modify VNF Information request              |
                                                  |     v                                                 |
+--------------------------+                      |  +-------------------------------------------+        |
|  TackerDB                |                      |  |                                           |        |
|                          |                      |  |    +------------------------+             |        |
|                          | 4. Update vnfdId     |  |    |  VnfLcmDriver          |             |        |
|                          |<---------------------+--+----+                        |             |        |
|                          |                      |  |    |                        |             |        |
|                          | 6. Update resourceId |  |    |                        |             |        |
|                          |<---------------------+--+----+                        |             |        |
|                          |                      |  |    |                        |             |        |
+--------------------------+                      |  |    +--+-------------------+-+             |        |
                                                  |  |       |  3. modify_start  | 5. modify_end |        |
+--------------------------+                      |  |       v                   v               |        |
|  +--------------------+  | 5-1. Replace config  |  |    +------------------------+             |        |
|  |  Kubernetes        |<-+----------------------+--+----+                        |             |        |
|  |  ConfigMap/Secret  |  |                      |  |    |  MgmtDriver            |             |        |
|  +--------------------+  |                      |  |    |                        |             |        |
|  +--------------------+  | 5-2. Replace Pod     |  |    |                        |             |        |
|  |  Kubernetes Pod    |<-+----------------------+--+----+                        |             |        |
|  +--------------------+  |                      |  |    +------------------------+             |        |
|    Kubernetes cluster    |                      |  |                                           |        |
+--------------------------+                      |  |   Tacker-conductor                        |        |
+--------------------------+                      |  +-------------------------------------------+        |
|    Hardware Resources    |                      |                                                       |
+--------------------------+                      +-------------------------------------------------------+

Request parameters for operation

User gives following modify parameter to “PATCH /vnflcm/v1/vnf_instances/{vnfInstanceId}” as VnfInfoModificationRequest data type in:

Definition of the VnfInfoModificationRequest data type

Attribute name	Cardinality	Parameter description
vnfInstanceName	0..1	String. “vnfInstanceName” attribute in “VnfInstance”.
vnfInstanceDescription	0..1	String. “vnfInstanceDescription” attribute in “VnfInstance”.
vnfdId	0..1	Identifier. “vnfdId” attribute in “VnfInstance”.
vnfConfigurableProperties	0..1	KeyValuePairs. “vnfConfigurableProperties” attribute in “VnfInstance”.
metadata	0..1	KeyValuePairs. “metadata” attribute in “VnfInstance”.
extensions	0..1	KeyValuePairs. “extensions” attribute in “VnfInstance”.
vimConnectionInfo	0..N	map (VimConnectionInfo). “vimConnectionInfo” attribute array in “VnfInstance”.
vimConnectionInfoDeleteIds	0..N	Identifier. To be deleted from the “vimConnectionInfo” attribute array in “VnfInstance”,

Following is a sample of request body:

{
  "vnfdId": "093c38b5-a731-4593-a578-d12e42596b3e"
}

Note

Refer to chapter REST API impact in the spec support-vnf-update-api-based-on-etsi-nfv-sol for the parameters supported by Tacker.

Using ConfigMap and Secret with Kubernetes

ConfigMap and Secret can be used in a Pod either by setting the environment variable or mounting to volume. The following are examples of the Kubernetes object file when using ConfigMap and Secret.

Sample file to define the Kubernetes ConfigMap and Secret:

---
apiVersion: v1
kind: ConfigMap
metadata:
  name: cm-data
data:
  cmKey1.txt: |
    configmap data
    foo
    bar
---
apiVersion: v1
kind: Secret
metadata:
  name: secret-data
stringData:
  password: 1mbb1G968fb1CUg
  secKey1.txt: |
    secret data
    baz

Sample file of Kubernetes object when using ConfigMap and Secret as environment variables:

apiVersion: v1
kind: Pod
metadata:
  name: env-test
spec:
  containers:
  - image: alpine
    name: alpine
    env:
    - name: CMENV
      valueFrom:
        configMapKeyRef:
          name: cm-data
          key: cmkey1.txt
    - name: SECENV
      valueFrom:
        secretKeyRef:
          name: secret-data
          key: password
    envFrom:
    - prefix: CM_
      configMapRef:
        name: cm-data
    - prefix: SEC_
      secretRef:
        name: secret-data
terminationGracePeriodSeconds: 0

Sample file of Kubernetes object when using ConfigMap and Secret by mounting to volume:

apiVersion: v1
kind: Pod
metadata:
  name: modify-VNF-volume-test
spec:
  containers:
  - image: alpine
    name: alpine
    volumeMounts:
    - name: cm-volume
      mountPath: /config
    - name: sec-volume
      mountPath: /etc/secrets
  volumes:
  - name: cm-volume
    configMap:
      name: cm-data
      defaultMode: 0666
      items:
      - key: cmKey1.txt
        path: cm/config.txt
  - name: secret-volume
    secret:
      secretName: secret-data
      defaultMode: 0600
      items:
      - key: secKey1.txt
        path: creds/secret.txt
terminationGracePeriodSeconds: 0

Sequence for operation

Note

The sequence described in the above and the below supposes that Tacker fetches the new VNF package in advance.

1. The Client sends a PATCH request to the “Individual VNF instance” resource.

2. Tacker-conductor sends modify VNF request to VnfLcmDriver.

3. VnfLcmDriver calls modify_start of MgmtDriver.

4. VnfLcmDriver updates VnfInstance.vnfdId in the TackerDB to the ID of the new VNFD.

5. VnfLcmDriver calls modify_end of MgmtDriver. modify_end uses the “kubectl replace” command to replace ConfigMap, Secret, and Pod.

   5-1. MgmtDriver sends request to replace config of ConfigMap and Secret to the VIM (Kubernetes).

   5-2. MgmtDriver sends request to recreate Pod to the VIM (Kubernetes).

   Note

   It is desirable to recreate only the Pods that refer the changed ConfigMap or Secret, but in this time we are considering to recreate all Pods defined in the same package. From the viewpoint of the data model of the VnfInfoModificationRequest, it is necessary to continue to examine which parameter is appropriate as a parameter for specifying this or whether a parameter for this purpose exists.

   Note

   If the image parameter in the manifest file for the Pod or Deployment has changed, the image will be replaced when the Pod is recreated.

6. VnfLcmDriver updates VnfInstance.instantiatedVnfInfo.vnfcResourceInfo.computeResource.resourceId in the TackerDB to the ID of the recreated Pod.

Alternatives

None

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

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

Hirofumi Noguchi<hirofumi.noguchi.rs@hco.ntt.co.jp>

Masaki Ueno<masaki.ueno.up@hco.ntt.co.jp>

Other contributors:

Yusuke Niimi<niimi.yusuke@fujitsu.com>

Yoshiyuki Katada<katada.yoshiyuk@fujitsu.com>

Ayumu Ueha<ueha.ayumu@fujitsu.com>

Work Items

1. Add preamble and postamble of Modify VNF Information operation using MgmtDriver.

2. Add a Updated manifest file that performs the following, to reflect configuration changes in VNF instance:

   • Update Kubernetes ConfigMap and Secret.

   • Recreate Kubernetes Pod.

3. Add Modify VNF operation to perform the following:

   • Update vnfdId and resourceId attribute in TackerDB.

Dependencies

None

Testing

Unit and functional tests will be added to cover cases required in the spec.

Documentation Impact

Complete user guide will be added to explain modifying VNF information from the perspective of VNF LCM APIs.

References

[1]

https://www.etsi.org/deliver/etsi_gs/NFV-SOL/001_099/003/02.06.01_60/gs_nfv-sol003v020601p.pdf