kuernetes yamlファイルの書き方
LinuCエヴァンジェリストの鯨井貴博@opensourcetechです。
はじめに
今回は、kubernetesを使う際に必要となるyamlファイルの書き方に関するメモです。
何となくこんな感じで書けばいいんだろうと、他の方が使っているファイルを真似ていますが、
「ルールってあるの？」と思ったので調べてみました。
yamlの例
公式サイトを見ると、
以下の例が載っています。
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
name: nginx-deployment
spec:
selector:
matchLabels:
app: nginx
replicas: 2 # tells deployment to run 2 pods matching the template
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.14.2
ports:
- containerPort: 80https://kubernetes.io/ja/docs/concepts/overview/working-with-objects/kubernetes-objects/
書かれている内容はシンプルで、
nginxバージョン1.14.2のコンテナイメージを使って、2つ(replicas)のコンテナを起動するというもの。
そして、それを"nginx-deployment"というDeployment名としています。
yamlの記載ルール
yamlの記載ルールですが、以下の3点。
・インデントは、スペース2つ
・"name:"の:(コロン)のあとは、スペースを1つ
metadata:
name: nginx-deployment
spec:
selector:
matchLabels:
app: nginx
・複数の情報を一つのyamlファイル内に書く場合、
"--"で区切る。
.
.
.
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: calico-kube-controllers
namespace: kube-system
---
apiVersion: policy/v1beta1
kind: PodDisruptionBudget
.
.
.
既にあるdeploymentなどからyamlを作成する
以下のDeploymentがあるとします。
kubeuser@kubemaster1:~$ kubectl get deployments,pods
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/nginx 2/2 2 2 23h
NAME READY STATUS RESTARTS AGE
pod/nginx-6c67f5ff6f-cc6x8 1/1 Running 0 23h
pod/nginx-6c67f5ff6f-rkwt2 1/1 Running 0 23h
この場合、kubectl getに""-o xxx.yamlオプションを付けることで、
yaml形式で出力させることが可能です。
kubeuser@kubemaster1:~$ kubectl get deployments nginx -o yaml
apiVersion: apps/v1
kind: Deployment
metadata:
annotations:
deployment.kubernetes.io/revision: "1"
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{"deployment.kubernetes.io/revision":"1"},"generation":1,"labels":{"app":"nginx"},"managedFields":[{"apiVersion":"apps/v1","fieldsType":"FieldsV1","fieldsV1":{"f:metadata":{"f:labels":{".":{},"f:app":{}}},"f:spec":{"f:progressDeadlineSeconds":{},"f:replicas":{},"f:revisionHistoryLimit":{},"f:selector":{"f:matchLabels":{".":{},"f:app":{}}},"f:strategy":{"f:rollingUpdate":{".":{},"f:maxSurge":{},"f:maxUnavailable":{}},"f:type":{}},"f:template":{"f:metadata":{"f:labels":{".":{},"f:app":{}}},"f:spec":{"f:containers":{"k:{\"name\":\"nginx\"}":{".":{},"f:image":{},"f:imagePullPolicy":{},"f:name":{},"f:resources":{},"f:terminationMessagePath":{},"f:terminationMessagePolicy":{}}},"f:dnsPolicy":{},"f:restartPolicy":{},"f:schedulerName":{},"f:securityContext":{},"f:terminationGracePeriodSeconds":{}}}}},"manager":"kubectl","operation":"Update","time":"2021-12-01T13:41:24Z"},{"apiVersion":"apps/v1","fieldsType":"FieldsV1","fieldsV1":{"f:metadata":{"f:annotations":{".":{},"f:deployment.kubernetes.io/revision":{}}},"f:status":{"f:availableReplicas":{},"f:conditions":{".":{},"k:{\"type\":\"Available\"}":{".":{},"f:lastTransitionTime":{},"f:lastUpdateTime":{},"f:message":{},"f:reason":{},"f:status":{},"f:type":{}},"k:{\"type\":\"Progressing\"}":{".":{},"f:lastTransitionTime":{},"f:lastUpdateTime":{},"f:message":{},"f:reason":{},"f:status":{},"f:type":{}}},"f:observedGeneration":{},"f:readyReplicas":{},"f:replicas":{},"f:updatedReplicas":{}}},"manager":"kube-controller-manager","operation":"Update","time":"2021-12-01T13:42:09Z"}],"name":"nginx","namespace":"default"},"spec":{"progressDeadlineSeconds":600,"replicas":2,"revisionHistoryLimit":10,"selector":{"matchLabels":{"app":"nginx"}},"strategy":{"rollingUpdate":{"maxSurge":"25%","maxUnavailable":"25%"},"type":"RollingUpdate"},"template":{"metadata":{"creationTimestamp":null,"labels":{"app":"nginx"}},"spec":{"containers":[{"image":"nginx:1.21.4","imagePullPolicy":"IfNotPresent","name":"nginx","resources":{},"terminationMessagePath":"/dev/termination-log","terminationMessagePolicy":"File"}],"dnsPolicy":"ClusterFirst","restartPolicy":"Always","schedulerName":"default-scheduler","securityContext":{},"terminationGracePeriodSeconds":30}}}}
creationTimestamp: "2021-12-07T13:16:14Z"
generation: 1
labels:
app: nginx
managedFields:
- apiVersion: apps/v1
fieldsType: FieldsV1
fieldsV1:
f:metadata:
f:labels:
.: {}
f:app: {}
f:spec:
f:progressDeadlineSeconds: {}
f:replicas: {}
f:revisionHistoryLimit: {}
f:selector:
f:matchLabels:
.: {}
f:app: {}
f:strategy:
f:rollingUpdate:
.: {}
f:maxSurge: {}
f:maxUnavailable: {}
f:type: {}
f:template:
f:metadata:
f:labels:
.: {}
f:app: {}
f:spec:
f:containers:
k:{"name":"nginx"}:
.: {}
f:image: {}
f:imagePullPolicy: {}
f:name: {}
f:resources: {}
f:terminationMessagePath: {}
f:terminationMessagePolicy: {}
f:dnsPolicy: {}
f:restartPolicy: {}
f:schedulerName: {}
f:securityContext: {}
f:terminationGracePeriodSeconds: {}
manager: kubectl
operation: Update
time: "2021-12-01T13:41:24Z"
- apiVersion: apps/v1
fieldsType: FieldsV1
fieldsV1:
f:metadata:
f:annotations:
.: {}
f:deployment.kubernetes.io/revision: {}
f:status:
f:availableReplicas: {}
f:conditions:
.: {}
k:{"type":"Available"}:
.: {}
f:lastTransitionTime: {}
f:lastUpdateTime: {}
f:message: {}
f:reason: {}
f:status: {}
f:type: {}
k:{"type":"Progressing"}:
.: {}
f:lastTransitionTime: {}
f:lastUpdateTime: {}
f:message: {}
f:reason: {}
f:status: {}
f:type: {}
f:observedGeneration: {}
f:readyReplicas: {}
f:replicas: {}
f:updatedReplicas: {}
manager: kube-controller-manager
operation: Update
time: "2021-12-01T13:42:09Z"
name: nginx
namespace: default
resourceVersion: "1442771"
selfLink: /apis/apps/v1/namespaces/default/deployments/nginx
uid: 2bb8b598-b3f9-4c36-a265-779c9123c2f5
spec:
progressDeadlineSeconds: 600
replicas: 2
revisionHistoryLimit: 10
selector:
matchLabels:
app: nginx
strategy:
rollingUpdate:
maxSurge: 25%
maxUnavailable: 25%
type: RollingUpdate
template:
metadata:
creationTimestamp: null
labels:
app: nginx
spec:
containers:
- image: nginx:1.21.4
imagePullPolicy: IfNotPresent
name: nginx
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
status:
availableReplicas: 2
conditions:
- lastTransitionTime: "2021-12-07T13:16:38Z"
lastUpdateTime: "2021-12-07T13:16:38Z"
message: Deployment has minimum availability.
reason: MinimumReplicasAvailable
status: "True"
type: Available
- lastTransitionTime: "2021-12-07T13:16:15Z"
lastUpdateTime: "2021-12-07T13:16:38Z"
message: ReplicaSet "nginx-6c67f5ff6f" has successfully progressed.
reason: NewReplicaSetAvailable
status: "True"
type: Progressing
observedGeneration: 1
readyReplicas: 2
replicas: 2
updatedReplicas: 2
なので、これをリダイレクトしてファイルに保存して使う方法があります。
kubeuser@kubemaster1:~$ kubectl get deployments nginx -o yaml > nginx.yaml
参考：JSON形式で出力する
ちなみに、"-o json"とすることでJSON形式での出力も可能です。
kubeuser@kubemaster1:~$ kubectl get deployments nginx -o json
{
"apiVersion": "apps/v1",
"kind": "Deployment",
"metadata": {
"annotations": {
"deployment.kubernetes.io/revision": "1",
"kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"apps/v1\",\"kind\":\"Deployment\",\"metadata\":{\"annotations\":{\"deployment.kubernetes.io/revision\":\"1\"},\"generation\":1,\"labels\":{\"app\":\"nginx\"},\"managedFields\":[{\"apiVersion\":\"apps/v1\",\"fieldsType\":\"FieldsV1\",\"fieldsV1\":{\"f:metadata\":{\"f:labels\":{\".\":{},\"f:app\":{}}},\"f:spec\":{\"f:progressDeadlineSeconds\":{},\"f:replicas\":{},\"f:revisionHistoryLimit\":{},\"f:selector\":{\"f:matchLabels\":{\".\":{},\"f:app\":{}}},\"f:strategy\":{\"f:rollingUpdate\":{\".\":{},\"f:maxSurge\":{},\"f:maxUnavailable\":{}},\"f:type\":{}},\"f:template\":{\"f:metadata\":{\"f:labels\":{\".\":{},\"f:app\":{}}},\"f:spec\":{\"f:containers\":{\"k:{\\\"name\\\":\\\"nginx\\\"}\":{\".\":{},\"f:image\":{},\"f:imagePullPolicy\":{},\"f:name\":{},\"f:resources\":{},\"f:terminationMessagePath\":{},\"f:terminationMessagePolicy\":{}}},\"f:dnsPolicy\":{},\"f:restartPolicy\":{},\"f:schedulerName\":{},\"f:securityContext\":{},\"f:terminationGracePeriodSeconds\":{}}}}},\"manager\":\"kubectl\",\"operation\":\"Update\",\"time\":\"2021-12-01T13:41:24Z\"},{\"apiVersion\":\"apps/v1\",\"fieldsType\":\"FieldsV1\",\"fieldsV1\":{\"f:metadata\":{\"f:annotations\":{\".\":{},\"f:deployment.kubernetes.io/revision\":{}}},\"f:status\":{\"f:availableReplicas\":{},\"f:conditions\":{\".\":{},\"k:{\\\"type\\\":\\\"Available\\\"}\":{\".\":{},\"f:lastTransitionTime\":{},\"f:lastUpdateTime\":{},\"f:message\":{},\"f:reason\":{},\"f:status\":{},\"f:type\":{}},\"k:{\\\"type\\\":\\\"Progressing\\\"}\":{\".\":{},\"f:lastTransitionTime\":{},\"f:lastUpdateTime\":{},\"f:message\":{},\"f:reason\":{},\"f:status\":{},\"f:type\":{}}},\"f:observedGeneration\":{},\"f:readyReplicas\":{},\"f:replicas\":{},\"f:updatedReplicas\":{}}},\"manager\":\"kube-controller-manager\",\"operation\":\"Update\",\"time\":\"2021-12-01T13:42:09Z\"}],\"name\":\"nginx\",\"namespace\":\"default\"},\"spec\":{\"progressDeadlineSeconds\":600,\"replicas\":2,\"revisionHistoryLimit\":10,\"selector\":{\"matchLabels\":{\"app\":\"nginx\"}},\"strategy\":{\"rollingUpdate\":{\"maxSurge\":\"25%\",\"maxUnavailable\":\"25%\"},\"type\":\"RollingUpdate\"},\"template\":{\"metadata\":{\"creationTimestamp\":null,\"labels\":{\"app\":\"nginx\"}},\"spec\":{\"containers\":[{\"image\":\"nginx:1.21.4\",\"imagePullPolicy\":\"IfNotPresent\",\"name\":\"nginx\",\"resources\":{},\"terminationMessagePath\":\"/dev/termination-log\",\"terminationMessagePolicy\":\"File\"}],\"dnsPolicy\":\"ClusterFirst\",\"restartPolicy\":\"Always\",\"schedulerName\":\"default-scheduler\",\"securityContext\":{},\"terminationGracePeriodSeconds\":30}}}}\n"
},
"creationTimestamp": "2021-12-07T13:16:14Z",
"generation": 1,
"labels": {
"app": "nginx"
},
"managedFields": [
{
"apiVersion": "apps/v1",
"fieldsType": "FieldsV1",
"fieldsV1": {
"f:metadata": {
"f:labels": {
".": {},
"f:app": {}
}
},
"f:spec": {
"f:progressDeadlineSeconds": {},
"f:replicas": {},
"f:revisionHistoryLimit": {},
"f:selector": {
"f:matchLabels": {
".": {},
"f:app": {}
}
},
"f:strategy": {
"f:rollingUpdate": {
".": {},
"f:maxSurge": {},
"f:maxUnavailable": {}
},
"f:type": {}
},
"f:template": {
"f:metadata": {
"f:labels": {
".": {},
"f:app": {}
}
},
"f:spec": {
"f:containers": {
"k:{\"name\":\"nginx\"}": {
".": {},
"f:image": {},
"f:imagePullPolicy": {},
"f:name": {},
"f:resources": {},
"f:terminationMessagePath": {},
"f:terminationMessagePolicy": {}
}
},
"f:dnsPolicy": {},
"f:restartPolicy": {},
"f:schedulerName": {},
"f:securityContext": {},
"f:terminationGracePeriodSeconds": {}
}
}
}
},
"manager": "kubectl",
"operation": "Update",
"time": "2021-12-01T13:41:24Z"
},
{
"apiVersion": "apps/v1",
"fieldsType": "FieldsV1",
"fieldsV1": {
"f:metadata": {
"f:annotations": {
".": {},
"f:deployment.kubernetes.io/revision": {}
}
},
"f:status": {
"f:availableReplicas": {},
"f:conditions": {
".": {},
"k:{\"type\":\"Available\"}": {
".": {},
"f:lastTransitionTime": {},
"f:lastUpdateTime": {},
"f:message": {},
"f:reason": {},
"f:status": {},
"f:type": {}
},
"k:{\"type\":\"Progressing\"}": {
".": {},
"f:lastTransitionTime": {},
"f:lastUpdateTime": {},
"f:message": {},
"f:reason": {},
"f:status": {},
"f:type": {}
}
},
"f:observedGeneration": {},
"f:readyReplicas": {},
"f:replicas": {},
"f:updatedReplicas": {}
}
},
"manager": "kube-controller-manager",
"operation": "Update",
"time": "2021-12-01T13:42:09Z"
}
],
"name": "nginx",
"namespace": "default",
"resourceVersion": "1442771",
"selfLink": "/apis/apps/v1/namespaces/default/deployments/nginx",
"uid": "2bb8b598-b3f9-4c36-a265-779c9123c2f5"
},
"spec": {
"progressDeadlineSeconds": 600,
"replicas": 2,
"revisionHistoryLimit": 10,
"selector": {
"matchLabels": {
"app": "nginx"
}
},
"strategy": {
"rollingUpdate": {
"maxSurge": "25%",
"maxUnavailable": "25%"
},
"type": "RollingUpdate"
},
"template": {
"metadata": {
"creationTimestamp": null,
"labels": {
"app": "nginx"
}
},
"spec": {
"containers": [
{
"image": "nginx:1.21.4",
"imagePullPolicy": "IfNotPresent",
"name": "nginx",
"resources": {},
"terminationMessagePath": "/dev/termination-log",
"terminationMessagePolicy": "File"
}
],
"dnsPolicy": "ClusterFirst",
"restartPolicy": "Always",
"schedulerName": "default-scheduler",
"securityContext": {},
"terminationGracePeriodSeconds": 30
}
}
},
"status": {
"availableReplicas": 2,
"conditions": [
{
"lastTransitionTime": "2021-12-07T13:16:38Z",
"lastUpdateTime": "2021-12-07T13:16:38Z",
"message": "Deployment has minimum availability.",
"reason": "MinimumReplicasAvailable",
"status": "True",
"type": "Available"
},
{
"lastTransitionTime": "2021-12-07T13:16:15Z",
"lastUpdateTime": "2021-12-07T13:16:38Z",
"message": "ReplicaSet \"nginx-6c67f5ff6f\" has successfully progressed.",
"reason": "NewReplicaSetAvailable",
"status": "True",
"type": "Progressing"
}
],
"observedGeneration": 1,
"readyReplicas": 2,
"replicas": 2,
"updatedReplicas": 2
}
}
おわりに
何もない状態から手書きするの大変だなと思っていたので、
yaml形式で出力する方法は便利ですね！