具有完全相同的 pod 标签的两个 Kubernetes Deployment

Question

假设我有两个完全相同的部署，除了部署名称：

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-d
spec:
  replicas: 3
  selector:
    matchLabels:
      app: mynginx
  template:
    metadata:
      labels:
        app: mynginx
    spec:
      containers:
      - name: nginx
        image: nginx
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-d2
spec:
  replicas: 3
  selector:
    matchLabels:
      app: mynginx
  template:
    metadata:
      labels:
        app: mynginx
    spec:
      containers:
      - name: nginx
        image: nginx

由于这两个部署具有相同的选择器和相同的 pod 模板，我希望看到三个 pods。但是，创建了六个 pods：

# kubectl get pods --show-labels
NAME                        READY   STATUS    RESTARTS   AGE     LABELS
nginx-d-5b686ccd46-dkpk7    1/1     Running   0          4m16s   app=mynginx,pod-template-hash=5b686ccd46
nginx-d-5b686ccd46-nz7wf    1/1     Running   0          4m16s   app=mynginx,pod-template-hash=5b686ccd46
nginx-d-5b686ccd46-vdtfr    1/1     Running   0          4m16s   app=mynginx,pod-template-hash=5b686ccd46
nginx-d2-5b686ccd46-nqmq7   1/1     Running   0          4m16s   app=mynginx,pod-template-hash=5b686ccd46
nginx-d2-5b686ccd46-nzrlc   1/1     Running   0          4m16s   app=mynginx,pod-template-hash=5b686ccd46
nginx-d2-5b686ccd46-qgjkn   1/1     Running   0          4m16s   app=mynginx,pod-template-hash=5b686ccd46

这是为什么？

Answer 1

考虑一下：pods 不是直接由部署管理，但部署管理 ReplicaSet。

这可以使用

来验证

kubectl get rs
NAME                  DESIRED   CURRENT   READY   AGE
nginx-d-5b686ccd46    3         3         3       74s
nginx-d2-7c76fbbbcb   3         3         0       74s

您可以通过指定选择器来选择要考虑将哪个 pods 用于副本集或部署。除此之外，每个部署都添加了自己的标签，以便能够区分哪些 pods 由其自己的副本集管理，哪些由其他副本集管理。

你也可以检查这个：

kubectl get pods --show-labels  
NAME                        READY   STATUS    RESTARTS   AGE   LABELS
nginx-d-5b686ccd46-7j4md    1/1     Running   0          4m    app=mynginx,pod-template-hash=5b686ccd46
nginx-d-5b686ccd46-9j7tx    1/1     Running   0          4m    app=mynginx,pod-template-hash=5b686ccd46
nginx-d-5b686ccd46-zt4ls    1/1     Running   0          4m    app=mynginx,pod-template-hash=5b686ccd46
nginx-d2-5b686ccd46-ddcr2   1/1     Running   0          75s   app=mynginx,pod-template-hash=5b686ccd46
nginx-d2-5b686ccd46-fhvm7   1/1     Running   0          79s   app=mynginx,pod-template-hash=5b686ccd46
nginx-d2-5b686ccd46-q99ww   1/1     Running   0          83s   app=mynginx,pod-template-hash=5b686ccd46

这些作为匹配标签添加到副本集：

spec:
  replicas: 3
  selector:
    matchLabels:
      app: mynginx
      pod-template-hash: 5b686ccd46

因为即使这些是相同的，您也可以检查 pods 并看到也有所有者参考：

kubectl get pod nginx-d-5b686ccd46-7j4md -o yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: "2021-10-28T14:53:17Z"
  generateName: nginx-d-5b686ccd46-
  labels:
    app: mynginx
    pod-template-hash: 5b686ccd46
  name: nginx-d-5b686ccd46-7j4md
  namespace: default
  ownerReferences:
  - apiVersion: apps/v1
    blockOwnerDeletion: true
    controller: true
    kind: ReplicaSet
    name: nginx-d-5b686ccd46
    uid: 7eb8fdaf-bfe7-4647-9180-43148a036184
  resourceVersion: "556"

可在此处找到更多相关信息：https://kubernetes.io/docs/concepts/overview/working-with-objects/owners-dependents/

因此部署（和副本集）可以消除由哪个 pods 管理的歧义，并且每个都确保所需的副本数。

具有完全相同的 pod 标签的两个 Kubernetes Deployment

Two Kubernetes Deployments with exactly the same pod labels

deployment

label

kubernetes