是否可以使用 Kubernetes 的
kubectl
命令生成 YAML?澄清一下 - 我不是在谈论从现有部署(如 kubectl get XXXX -o yaml
)生成 YAML,而是在谈论生成 YAML 文件以首次创建 Pod、Service、Ingress 等。
PS:有一种方法可以从 kubernetes.io 站点(1,2)获取 YAML 文件,但我正在寻找是否有一种方法可以仅使用 kubectl 生成 YAML 模板。
create
中的命令kubectl
可以解决这个问题,并取代了过去使用的run
:让我们想象一下您想要创建一个运行nginx:latest Docker 镜像的Deployment。
# kubectl create deployment my_deployment --image=busybox --dry-run=client --output=yaml
apiVersion: apps/v1
kind: Deployment
metadata:
creationTimestamp: null
labels:
app: my_deployment
name: my_deployment
spec:
replicas: 1
selector:
matchLabels:
app: my_deployment
strategy: {}
template:
metadata:
creationTimestamp: null
labels:
app: my_deployment
spec:
containers:
- image: busybox
name: busybox
resources: {}
status: {}
我们来分析一下各个参数:
my_deployment
是您选择的 Deployment 名称--image
是你要部署的Docker镜像--dry-run=client
不会执行资源创建,主要用于验证。 对于旧版本的 Kubernetes,将“client”替换为“true”。 client
和 server
都不会实际创建资源,但如果在没有试运行的情况下无法创建资源(即:资源已存在),server
将返回错误。差异非常微妙。--output=yaml
将 Deployment 资源的 YAML 定义打印到 标准输出。显然,您只需使用很少的 Kubernetes 默认资源即可执行此选项:
# kubectl create
clusterrole Create a ClusterRole.
clusterrolebinding Create a ClusterRoleBinding for a particular ClusterRole
configmap Create a configmap from a local file, directory or literal value
deployment Create a deployment with the specified name.
job Create a job with the specified name.
namespace Create a namespace with the specified name
poddisruptionbudget Create a pod disruption budget with the specified name.
priorityclass Create a priorityclass with the specified name.
quota Create a quota with the specified name.
role Create a role with single rule.
rolebinding Create a RoleBinding for a particular Role or ClusterRole
secret Create a secret using specified subcommand
service Create a service using specified subcommand.
serviceaccount Create a service account with the specified name
据此,您可以渲染模板,而无需事先部署资源。
此外
kubectl explain
可用于不同的资源。它不会为标准 Pod 生成 yaml 文件,但会显示一个描述,例如:
kubectl explain pods
获取 pod 中某个部分/属性的详细信息:
kubectl explain pods.spec
还可以将结果解释输出到 yaml 文件并进行编辑:
kubectl explain pods > mypod.yaml
并且! 与
kubectl explain pod --recursive
无需解释即可了解资源的整体结构;导出到 yaml 文件可以代表目标资源的空骨架;下面是 pod 的一段:
KIND: Pod
VERSION: v1
DESCRIPTION:
Pod is a collection of containers that can run on a host. This resource is
created by clients and scheduled onto hosts.
FIELDS:
apiVersion <string>
kind <string>
metadata <Object>
annotations <map[string]string>
clusterName <string>
creationTimestamp <string>
deletionGracePeriodSeconds <integer>
deletionTimestamp <string>
finalizers <[]string>
generateName <string>
generation <integer>
labels <map[string]string>
managedFields <[]Object>
apiVersion <string>
fieldsType <string>
fieldsV1 <map[string]>
manager <string>
operation <string>
time <string>
name <string>
namespace <string>
ownerReferences <[]Object>
apiVersion <string>
blockOwnerDeletion <boolean>
controller <boolean>
kind <string>
name <string>
uid <string>
resourceVersion <string>
selfLink <string>
uid <string>
spec <Object>
activeDeadlineSeconds <integer>
affinity <Object>
nodeAffinity <Object>
preferredDuringSchedulingIgnoredDuringExecution <[]Object>
preference <Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
matchFields <[]Object>
key <string>
operator <string>
values <[]string>
weight <integer>
requiredDuringSchedulingIgnoredDuringExecution <Object>
nodeSelectorTerms <[]Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
matchFields <[]Object>
key <string>
operator <string>
values <[]string>
podAffinity <Object>
preferredDuringSchedulingIgnoredDuringExecution <[]Object>
podAffinityTerm <Object>
labelSelector <Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
matchLabels <map[string]string>
namespaces <[]string>
topologyKey <string>
weight <integer>
requiredDuringSchedulingIgnoredDuringExecution <[]Object>
labelSelector <Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
matchLabels <map[string]string>
namespaces <[]string>
topologyKey <string>
podAntiAffinity <Object>
preferredDuringSchedulingIgnoredDuringExecution <[]Object>
podAffinityTerm <Object>
labelSelector <Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
.
.
.
您可以使用yq工具根据现有资源生成没有特定元数据(或其他字段)的yaml模板。例如:
kubectl get deploy my-nginx -o yaml | \
yq eval 'del(.metadata.resourceVersion, .metadata.uid, .metadata.annotations, .metadata.creationTimestamp, .metadata.selfLink, .metadata.managedFields, .status.conditions)' \
- > nginx_template.yaml
稍后您可以使用
kubectl apply -f nginx_template.yaml
应用该资源。它适用于其他资源类型,包括CustomResourceDefinitions。
(我知道这并不能完全回答OP问题,但这个主题可能会引导人们寻找这个特定的答案)。