Kubernetes Operator for vSphere VM

Kubernetes Operator
for vSphere VM
KubernetesからvSphereのVMを作成してみる
VMware DevOps Meetup #3

今日のお話
KubernetesのOperatorを利用して、Kubernetes APIからvSphere上に仮想マシンを作
ります。
紹介するOperatorはPoC向けでありプロダクション向けのものではありません。
VMworld 2019 Session: Kubernetes Operators for VMware Enterprise PKS and
VMware Cloud PKS [CODE1360U] の内容をベースにしています。
● Streaming : https://videos.vmworld.com/global/2019/videoplayer/27913
● Presentation : https://cms.vmworldonline.com/event_data/12/session_notes/CODE1360U.pdf
● Github : https://github.com/embano1/kopf-operator-vmworld

Master3
Master2
Node
Node
Master1 Node
Client
(kubectl)
API Server
Cluster State Store
(etcd)
kubelet
Container
Runtime
Pod
(Container)
Controller Manager
Controllers
Scheduler
Kubernetesのアーキテクチャ

KubernetesのReconciliation Loop
Observe
Analyze
Act
期待する状態を現在
の状態を比較
状態の差異を
埋める
API Serverへ
現在の状態を
問い合わせる
● Deployment
● ReplicaSet
● StatefulSet
● ...etc

Operatorとは
Operatorは”Custom Resource Defnition”と”Custom Controller”の組み合わせ。
ステートフルなアプリケーション等に対する運用のナレッジをコード化し、Kubernetes
API上でアプリケーションライフサイクルの管理を実現する。
Operator CRD
(Custom Resource Definition)
Controller
(Custom Controller)
＋＝
● Custom Resource Definition : KubernetesのAPI上に任意のリソースを追加する
● Custom Controller : CRDによって定義されたカスタムリソースのライフサイクルを管理する
https://coreos.com/blog/introducing-operators.html
Introducing Operators: Putting Operational Knowledge into Software
2016/11/3 Brandon Philips

Operatorの例
● MySQL
● Elasticsearch
● Kafka
● Istio
● Sysdig Agent
● Velero
● Amazon RDS
● etc...
https://operatorhub.io/

Master3
Master2
Node
Node
Master1 Node
Client
(kubectl)
API Server
Cluster State Store
(etcd)
kubelet
Container
Runtime
Pod
(Container)
Controller Manager
Controllers
Scheduler
vSphereへの対応
Custom Controller
CRD

VmGroup(vg)をCRDとして定義する。
Custom Resource Definition(CRD)
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
name: vmgroups.vsphere.vmware.com
spec:
scope: Namespaced
group: vsphere.vmware.com
versions:
- name: v1alpha1
served: true
storage: true
names:
kind: VmGroup
plural: vmgroups
singular: vmgroup
shortNames:
- vg
additionalPrinterColumns:
- name: Template
type: string
priority: 0
JSONPath: .spec.template
description: Template this VM group is based on
- name: Desired
type: integer
priority: 0
JSONPath: .spec.replicas
description: The number of configured replicas in this VM group
- name: Available
type: string
priority: 0
JSONPath: .status.vm_operator.currentReplicas
description: The number of available replicas in this VM group
- name: Phase
type: string
priority: 0
JSONPath: .status.vm_operator.phase
description: Deployment status of this VM group

Controllerの作成 - Operator Frameworkの利用
● kopf : Kubernetes Operator Pythonic Framework
○ https://github.com/zalando-incubator/kopf
○ Kubernetes APIの詳細を知らなくても Reconsilication Logicが実装可能
○ Supported Language : Python
● その他のFramework
○ Operator Framework - https://github.com/operator-framework
■ Supported Languanges : Golang (HelmチャートやAnsible Playbookの再利用が可能)
○ Kubebuilder - https://github.com/kubernetes-sigs/kubebuilder
■ Supported Languages: Golang
○ Google Metacontroller - https://metacontroller.app
■ Supported Languages: Python, JavaScript,

Kopfを使って、Kubernetes API上でVmGroup(vg)をCRDのライフサイクルを管理する
ためのコントローラーを作成する。
Custom Controller
import kopf
from pyVim.connect import Disconnect
from pyVmomi import vim
@kopf.on.event('vsphere.vmware.com', 'v1alpha1', 'vmgroups')
def vm_operator(event, spec, meta, status, logger, **_):
sleep(3)
if event_type == "DELETED":
delete_vm_group(vmgroup, logger)
return
try:
phase = status['vm_operator']['phase']
except KeyError:
phase = "PENDING"
if phase == "PENDING":
exists = vm_group_exists(vmgroup)
...
https://github.com/embano1/kopf-operator-vmworld/blob/master/controller.py
...
def create_vm_group(vmgroup_name: str, vmgroup_spec: Dict[str, str], logger:
logging.Logger) -> int:
try:
vsphere.create_folder(dc, vmgroup_name)
except vsphere.ObjectAlreadyExists as e:
logger.warn(str(e))
return
try:
created = vsphere.clone_vm(content, dc, CLUSTER, DATASTORE, vmgroup_name,
vmgroup_spec, logger)
except vsphere.CloneError as e:
logger.warn(str(e))
return -1
return created
Reconciliation Loopの実装

Custom Resourceの作成
CRDとして作成した VmGroup リソースを作成する。
apiVersion: vsphere.vmware.com/v1alpha1
kind: VmGroup
metadata:
name: kopf-example
labels:
vmdevops: "0918"
spec:
cpu: 1
memory: 1
template: kopf-vm-template
replicas: 3
# kubectl apply -f demo.yaml
vmgroup.vsphere.vmware.com/kopf-example created
# kubectl get vmgroup
NAME TEMPLATE DESIRED AVAILABLE PHASE
kopf-example kopf-vm-template 3 3 READY

Project Pacific ここ
Project Pacific – Technical Overview : https://blogs.vmware.com/vsphere/2019/08/project-pacific-technical-overview.html

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