Istio Workload Entry and Workload Group

WorkloadEntry

• 為什麼需要WorkloadEntry CR?

• ·自v1.6開始，Istio在其流量管理功能組中引入了WorkloadEntry這一新的資源類型
• WorkloadEntry CR用于抽象非Kubernetes托管的工作負載，例如虛拟機（VM）執行個體和裸伺服器等，進而将虛拟機加入到網格中
• 于是，這些VM或裸伺服器，亦可作為與Kubernetes叢集上的Pod等同的工作負載，并具備流量管理、安全管理、可視化等能力
• ServiceEntry對象可根據指定的标簽器篩選VM，進而讓ServiceEntry專注于服務定義，而由WorkloadEntry負責定義各端點
• 是以：WorkloadEntry CR的引入，大大簡化了将VM加入Istio網格的複雜度

• Istio在其v1.8版本中對VM的支援有了進一步的增強

• VM自動注冊：使用WorkloadGroup CR，将VM執行個體自動注冊為Istio上的WorkloadEntry
• 智能DNS代理：使用Sidecar DNS Proxy，緩存網格中的endpoint，以及由ServiceEntry建立的endpoint

• 虛拟機通路網格内的服務無需再配置/etc/hosts

• 是以：WorkloadGroup和WorkloadEntry能夠友善使用者将虛拟機上的服務注冊到網格内

WorkloadEntry CR 資源規範

~# kubectl explain workloadgroup
KIND:     WorkloadGroup
VERSION:  networking.istio.io/v1beta1

DESCRIPTION:
     <empty>

FIELDS:
   apiVersion   <string>
     APIVersion defines the versioned schema of this representation of an
     object. Servers should convert recognized schemas to the latest internal
     value, and may reject unrecognized values. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources

   kind   <string>
     Kind is a string value representing the REST resource this object
     represents. Servers may infer this from the endpoint the client submits
     requests to. Cannot be updated. In CamelCase. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds

   metadata   <Object>
     Standard object's metadata. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata

   spec  <Object>

   status   <>      

~# kubectl explain workloadentry
KIND:     WorkloadEntry
VERSION:  networking.istio.io/v1beta1

DESCRIPTION:
     <empty>

FIELDS:
   apiVersion   <string>
     APIVersion defines the versioned schema of this representation of an
     object. Servers should convert recognized schemas to the latest internal
     value, and may reject unrecognized values. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources

   kind   <string>
     Kind is a string value representing the REST resource this object
     represents. Servers may infer this from the endpoint the client submits
     requests to. Cannot be updated. In CamelCase. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds

   metadata   <Object>
     Standard object's metadata. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata

   spec  <Object>
     Configuration affecting VMs onboarded into the mesh. See more details at:
     https://istio.io/docs/reference/config/networking/workload-entry.html

   status   <>      

參考文檔

 workload-entry：https://istio.io/latest/docs/reference/config/networking/workload-entry/