文章目录
❌报错信息排查过程✅问题解决
❌报错信息
提取报错信息【 unknown field “spec.selector.replicas”】【 unknown field “spec.selector.template”】
[root@master ~]# kubectl apply -f nginx-deployment.yaml
Error from server (BadRequest): error when creating "nginx-deployment.yaml": Deployment in version "v1" cannot be handled as a Deployment: strict decoding error: unknown field "spec.selector.replicas", unknown field "spec.selector.template"
排查过程
根据报错信息，排查一下nginx-deployment YAML文件。
原nginx-deployment.yaml文件（编写有误）
# nginx-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deploy
namespace: default
labels:
chapter: first-app
spec:
selector:
matchLabels:
app: nginx
replicas: 2
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.7.9
ports:
- containerPort: 80
首先，使用YAML、YML在线编辑(校验)器校对一下此YAML文件格式是否正确。未发现异常。
其次，根据报错信息，定位到【unknown field “spec.selector.replicas”】【unknown field “spec.selector.template”】这两处的字段中的replicas和template这两个关键字。提示的大概意思是在spec.selector字段值里未找到这两个属性，属于未知属性。
通过运行kubectl explain deployment 查看其中字段属性位置包含关系情况。
[root@master ~]# kubectl explain deployment
KIND: Deployment
VERSION: apps/v1
DESCRIPTION:
Deployment enables declarative updates for Pods and ReplicaSets.
FIELDS:
apiVersion
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
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
Standard object's metadata. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
spec
Specification of the desired behavior of the Deployment.
status
Most recently observed status of the Deployment.
查看replicas层级关系kubectl explain deployment.spec
replicas这一字段属于spec下一级。不应该在selector这一字段的下级。
同理，template这一字段也属于spec下一级，不应该在selector这一字段的下级。
[root@master ~]# kubectl explain deployment.spec
KIND: Deployment
VERSION: apps/v1
RESOURCE: spec
DESCRIPTION:
Specification of the desired behavior of the Deployment.
DeploymentSpec is the specification of the desired behavior of the
Deployment.
FIELDS:
minReadySeconds
Minimum number of seconds for which a newly created pod should be ready
without any of its container crashing, for it to be considered available.
Defaults to 0 (pod will be considered available as soon as it is ready)
paused
Indicates that the deployment is paused.
progressDeadlineSeconds
The maximum time in seconds for a deployment to make progress before it is
considered to be failed. The deployment controller will continue to process
failed deployments and a condition with a ProgressDeadlineExceeded reason
will be surfaced in the deployment status. Note that progress will not be
estimated during the time a deployment is paused. Defaults to 600s.
replicas
Number of desired pods. This is a pointer to distinguish between explicit
zero and not specified. Defaults to 1.
revisionHistoryLimit
The number of old ReplicaSets to retain to allow rollback. This is a
pointer to distinguish between explicit zero and not specified. Defaults to
10.
selector
Label selector for pods. Existing ReplicaSets whose pods are selected by
this will be the ones affected by this deployment. It must match the pod
template's labels.
strategy
The deployment strategy to use to replace existing pods with new ones.
template
Template describes the pods that will be created.
️修改完成后的nginx-deployment.yaml，如下：
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deploy
namespace: default
labels:
chapter: first-app
spec:
replicas: 2
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.7.9
ports:
- containerPort: 80
✅问题解决
重新运行该YAML文件，运行成功。
[root@master ~]# kubectl apply -f nginx-deployment.yaml
deployment.apps/nginx-deploy created
[root@master ~]# kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
nginx-deploy 0/2 2 0 26s
[root@master ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-deploy-7759cfdc55-q4622 1/1 Running 0 33s
nginx-deploy-7759cfdc55-skcgp 1/1 Running 0 33s
完结
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