对于kubernetes 资源可以使用加载 yaml 标记语言的方式，进行自定义:
YAML（/ˈjæməl/，尾音类似camel骆驼）是一个可读性高，用来表达数据序列化的格式。YAML参考了其他多种语言，包括：C语言、Python、Perl，并从XML、电子邮件的数据格式（RFC 2822）中获得灵感。Clark Evans在2001年首次发表了这种语言[1]，另外Ingy döt Net与Oren Ben-Kiki也是这语言的共同设计者[2]。当前已经有数种编程语言或脚本语言支持（或者说解析）这种语言。 YAML是"YAML Ain't a Markup Language"（YAML不是一种标记语言）的递归缩写。在开发的这种语言时，YAML 的意思其实是："Yet Another Markup Language"（仍是一种标记语言）[3]，但为了强调这种语言以数据做为中心，而不是以标记语言为重点，而用反向缩略语重命名。
使用YAML用于k8s的定义将给你一些好处，包括：
- 便捷性：你将不再需要添加大量的参数到命令行中执行命令
- 可维护性：YAML文件可以通过源头控制，可以跟踪每次的操作
- 灵活性：通过YAML你将可以创建比命令行更加复杂的结构
YAML是一个JSON的超集，意味着任何有效JSON文件也都是一个有效的YAML文件。所以一方面，如果你知道JSON，你只是要去写自己的YAML（而不是阅读别人的）也就可以了。另一方面，不太可能,不幸的是，尽管你尝试去网上找到例子，但是他们通常都不是JSON，所以我们可能需要去习惯它。不过，有JSON的情况下可能会更方便，这样你将会很开心你懂得JSON。
幸运的是，YAML只有两种结构类型你需要知道：
- Lists
- YAML lists 是一个序列的对象
- Maps
- Maps让你将键值组合，你就可以更加方便的去设置配置信息
查看pod 资源清单
[root@kube ~]# kubectl get pod nginx-app-7756966bc9-qrksb -o yaml
//这是一个通过 kubectl run 方式运行的 pod ，那么我们可以手动定义一个 和这个类似的 yaml 配置文件进行加载然后生成pod
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: "2019-07-16T06:39:02Z"
generateName: nginx-app-7756966bc9-
labels:
pod-template-hash: 7756966bc9
run: nginx-app
name: nginx-app-7756966bc9-qrksb
namespace: default
ownerReferences:
- apiVersion: apps/v1
blockOwnerDeletion: true
controller: true
kind: ReplicaSet
name: nginx-app-7756966bc9
uid: 51997507-0ad5-4f71-86db-3ad6eff70171
resourceVersion: "603662"
selfLink: /api/v1/namespaces/default/pods/nginx-app-7756966bc9-qrksb
uid: 7035cfbd-a8f3-45a9-933c-4ce1cef45183
spec:
containers:
- image: nginx:alpine
imagePullPolicy: IfNotPresent
name: nginx-app
ports:
- containerPort: 80
protocol: TCP
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: default-token-bsthb
readOnly: true
dnsPolicy: ClusterFirst
enableServiceLinks: true
nodeName: kube.node1
priority: 0
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
serviceAccount: default
serviceAccountName: default
terminationGracePeriodSeconds: 30
tolerations:
- effect: NoExecute
key: node.kubernetes.io/not-ready
operator: Exists
tolerationSeconds: 300
- effect: NoExecute
key: node.kubernetes.io/unreachable
operator: Exists
tolerationSeconds: 300
volumes:
- name: default-token-bsthb
secret:
defaultMode: 420
secretName: default-token-bsthb
status:
conditions:
- lastProbeTime: null
lastTransitionTime: "2019-07-16T06:39:02Z"
status: "True"
type: Initialized
- lastProbeTime: null
lastTransitionTime: "2019-07-16T06:39:36Z"
status: "True"
type: Ready
- lastProbeTime: null
lastTransitionTime: "2019-07-16T06:39:36Z"
status: "True"
type: ContainersReady
- lastProbeTime: null
lastTransitionTime: "2019-07-16T06:39:02Z"
status: "True"
type: PodScheduled
containerStatuses:
- containerID: docker://6f50a8038d1f9b484c3af46fa21ef0bdce963b95c4f7f5980302bc70ca46eea6
image: nginx:alpine
imageID: docker-pullable://nginx@sha256:17bd1698318e9c0f9ba2c5ed49f53d690684dab7fe3e8019b855c352528d57be
lastState: {}
name: nginx-app
ready: true
restartCount: 0
state:
running:
startedAt: "2019-07-16T06:39:36Z"
hostIP: 10.2.61.22
phase: Running
podIP: 10.244.2.7
qosClass: BestEffort
startTime: "2019-07-16T06:39:02Z"
[root@kube ~]#
针对yaml 格式我们对如下进行分析：
#maps 是key|value 的组合，list 是key[args,args ，多个项的组合]用破折号（-）开头
apiVersion: v1 //maps kind: Pod //maps metadata: name: rss-site //maps labels: app: web /maps spec: //maps containers: //list name - name: front-end //list参数子项是maps image: nginx //list 参数子项是maps ports: - containerPort: 80 //list 参数子项maps - name: rss-reader image: nickchase/rss-php-nginx:v1 ports: - containerPort: 88
创建一个简单的yaml 文件
root@kube test]# cat pod-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-test
namespace: default
labels:
app: myapp
tier: frontend
spec:
containers:
- name: mytest
image: nginx:latest
[root@kube test]#
[root@kube test]# kubectl create -f pod-demo.yaml
pod/pod-test created
[root@kube test]# kubectl get pods
NAME READY STATUS RESTARTS AGE
busy1-78c9f4b47-pm2qx 0/1 CrashLoopBackOff 22 100m
busy2-7f9dbf96d6-2d778 1/1 Running 0 2d23h
busy3-9877c76bf-ts5rl 1/1 Running 0 2d23h
nginx-7bb7cd8db5-6sgvp 1/1 Running 0 3d
nginx-app-54c844949f-6zlmr 0/1 ContainerCreating 0 41h
nginx-app-54c844949f-n82d6 1/1 Running 0 2d
nginx-app-54c844949f-xmkb8 1/1 Running 0 2d
nginx-app-7756966bc9-qrksb 1/1 Running 0 2d2h
pod-test 0/1 ContainerCreating 0 1s
[root@kube test]#
[root@kube test]# kubectl describe pod pod-test
Name: pod-test
Namespace: default
Priority: 0
Node: kube.node1/10.2.61.22
Start Time: Thu, 18 Jul 2019 16:44:23 +0800
Labels: app=myapp
tier=frontend
Annotations: <none>
Status: Running
IP: 10.244.2.12
Containers:
mytest:
Container ID: docker://4e40fc5b6cae440881cea707b79c2d17692c47d75df69a571fa0e7d57dff5e3a
Image: nginx:latest
Image ID: docker-pullable://nginx@sha256:b4b9b3eee194703fc2fa8afa5b7510c77ae70cfba567af1376a573a967c03dbb
Port: <none>
Host Port: <none>
State: Running
Started: Thu, 18 Jul 2019 16:44:46 +0800
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-bsthb (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-bsthb:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-bsthb
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 62s default-scheduler Successfully assigned default/pod-test to kube.node1
Normal Pulling 61s kubelet, kube.node1 Pulling image "nginx:latest"
Normal Pulled 40s kubelet, kube.node1 Successfully pulled image "nginx:latest"
Normal Created 40s kubelet, kube.node1 Created container mytest
Normal Started 39s kubelet, kube.node1 Started container mytest
[root@kube test]#
[root@kube ~]# kubectl api-versions
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1
apiregistration.k8s.io/v1beta1
apps/v1
apps/v1beta1
apps/v1beta2
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
autoscaling/v2beta2
batch/v1
batch/v1beta1
certificates.k8s.io/v1beta1
coordination.k8s.io/v1
coordination.k8s.io/v1beta1
events.k8s.io/v1beta1
extensions/v1beta1
networking.k8s.io/v1
networking.k8s.io/v1beta1
node.k8s.io/v1beta1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
scheduling.k8s.io/v1
scheduling.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1
[root@kube ~]# kubectl explain pods
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>
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/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/api-conventions.md#types-kinds
metadata <Object>
Standard object's metadata. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata
spec <Object>
Specification of the desired behavior of the pod. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status
status <Object>
Most recently observed status of the pod. This data may not be up to date.
Populated by the system. Read-only. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status
[root@kube ~]#