Kubernetes實戰指南（三十三）：都0202了，你還在手寫k8s的yaml檔案？
阿新 • • 發佈：2020-08-19
目錄
1. k8s的yaml檔案到底有多複雜
Kubernetes建立、更新、刪除資源等操作時均可以使用json或yaml檔案進行操作，更新和刪除可以依賴之前的檔案進行更改，但是建立具有多變形，往往編輯起來比較複雜，容器出錯，而且k8s的配置項實在太多，稍微不注意就會犯錯。要寫好一個yaml檔案，你需要了解yaml的語法，需要掌握k8s的各種配置，對於一個k8s的初學者而言，這將是一件很難的事情。
比如我們看一個同時建立一個Deployment、Service、Ingress的yaml檔案內容：
--- apiVersion: v1 kind: Service metadata: labels: app: test-yaml name: test-yaml namespace: freeswitch spec: ports: - name: container-1-web-1 port: 8080 protocol: TCP targetPort: 8080 selector: app: test-yaml sessionAffinity: None type: ClusterIP --- apiVersion: networking.k8s.io/v1beta1 kind: Ingress metadata: creationTimestamp: null name: test-yaml spec: rules: - host: test.com http: paths: - backend: serviceName: test-yaml servicePort: 8080 path: / --- apiVersion: apps/v1 kind: Deployment metadata: labels: app: test-yaml name: test-yaml namespace: freeswitch spec: replicas: 3 selector: matchLabels: app: test-yaml strategy: rollingUpdate: maxSurge: 1 maxUnavailable: 0 type: RollingUpdate template: metadata: annotations: info: test for yaml labels: app: test-yaml spec: affinity: podAntiAffinity: preferredDuringSchedulingIgnoredDuringExecution: - podAffinityTerm: labelSelector: matchExpressions: - key: app operator: In values: - test-yaml topologyKey: kubernetes.io/hostname weight: 100 containers: - env: - name: TZ value: Asia/Shanghai - name: LANG value: C.UTF-8 image: nginx imagePullPolicy: Always lifecycle: {} livenessProbe: failureThreshold: 2 initialDelaySeconds: 30 periodSeconds: 10 successThreshold: 1 tcpSocket: port: 8080 timeoutSeconds: 2 name: test-yaml ports: - containerPort: 8080 name: web protocol: TCP readinessProbe: failureThreshold: 2 initialDelaySeconds: 30 periodSeconds: 10 successThreshold: 1 tcpSocket: port: 8080 timeoutSeconds: 2 resources: limits: cpu: 195m memory: 375Mi requests: cpu: 10m memory: 10Mi securityContext: allowPrivilegeEscalation: false capabilities: {} privileged: false procMount: Default readOnlyRootFilesystem: false runAsNonRoot: false volumeMounts: - mountPath: /usr/share/zoneinfo/Asia/Shanghai name: tz-config - mountPath: /etc/localtime name: tz-config - mountPath: /etc/timezone name: timezone dnsPolicy: ClusterFirst hostAliases: - hostnames: - www.baidu.com ip: 114.114.114.114 imagePullSecrets: - name: myregistrykey - name: myregistrykey2 restartPolicy: Always securityContext: {} volumes: - hostPath: path: /usr/share/zoneinfo/Asia/Shanghai type: "" name: tz-config - hostPath: path: /etc/timezone type: "" name: timezone
這是一個包含了Service、Ingress、Deployment比較常用並且沒有用到高階功能的yaml配置，就已經有上百行，如果是在添加了一些高階配置或者是Deployment中的容器不止一個，這個yaml會更大，就會造成一種視覺上疲勞，更改起來也比較麻煩而且非常容易出錯。
2. 基於圖形化的方式自動生成yaml
2.1 k8s圖形化管理工具Ratel安裝
本次採用Ratel自動生成yaml檔案，Ratel安裝文件：https://github.com/dotbalo/ratel-doc/blob/master/cluster/Install.md
2.2 使用Ratel建立生成yaml檔案
2.2.1 基本配置
安裝完成後，可以生成、建立管理常用的k8s核心資源，比如建立一個Deployment：
點選Deployment -- 建立如圖所示：
之後可以填寫一些基本的配置資訊，比如Deployment名稱、副本數、標籤資訊等，當然也可以點選必須/儘量部署至不同宿主機進行Pod親和力的配置
同時也可新增一些複雜的配置，比如核心配置、容忍配置、節點親和力快捷配置：
2.2.2 親和力配置
基本配置編譯完成以後，點選NEXT，下一個配置親和力配置，如果上一頁使用了親和力快捷鍵，這邊會自動生成親和力配置，你可以再次編輯或者新增、刪除：
2.2.3 儲存配置
親和力配置完成以後，可以點選NEXT進行儲存配置，目前支援volume和projectedVolume配置，volume支援configMap、Secret、HostPath、PVC、NFS、Empty等常用型別的配置：
2.2.4 容器配置
接下來是容器配置，支援常用的容器配置，當然也可以新增多個容器：
稍微複製一點的配置：
2.2.4 初始化容器配置
初始化容器和容器配置類似
2.2.5 Service和Ingress配置
建立Deployment時可以一鍵新增Service和Ingress，新增Service時會自動讀取容器的埠配置，新增Ingress時會自動讀取Service配置
2.2.6 建立資源或生成yaml檔案
上述配置完成以後，可以選擇建立資源或生成yaml檔案，假如點選生成yaml檔案，會自動生成Service、Ingress、Deployment的yaml檔案，可以直接拿著使用：
生成的內容如下：
---
apiVersion: v1
kind: Service
metadata:
creationTimestamp: null
labels:
app: test-yaml
name: test-yaml
namespace: default
spec:
ports:
- name: container-1-web-1
port: 8080
protocol: TCP
targetPort: 8080
selector:
app: test-yaml
sessionAffinity: None
type: ClusterIP
status:
loadBalancer: {}
---
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
creationTimestamp: null
name: test-yaml
spec:
rules:
- host: test.com
http:
paths:
- backend:
serviceName: test-yaml
servicePort: 8080
path: /
status:
loadBalancer: {}
---
apiVersion: apps/v1
kind: Deployment
metadata:
creationTimestamp: null
labels:
app: test-yaml
name: test-yaml
namespace: default
spec:
replicas: 3
selector:
matchLabels:
app: test-yaml
strategy:
rollingUpdate:
maxSurge: 1
maxUnavailable: 0
type: RollingUpdate
template:
metadata:
creationTimestamp: null
labels:
app: test-yaml
spec:
affinity:
nodeAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- preference:
matchExpressions:
- key: loki
operator: In
values:
- "true"
weight: 100
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: master
operator: NotIn
values:
- "true"
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- key: app
operator: In
values:
- test-yaml
topologyKey: kubernetes.io/hostname
containers:
- args:
- '*.jar --server.port=80'
command:
- java -jar
env:
- name: TZ
value: Asia/Shanghai
- name: LANG
value: C.UTF-8
- name: POD_IP
valueFrom:
fieldRef:
fieldPath: status.podIP
envFrom:
- configMapRef:
name: testcm
image: nginx
imagePullPolicy: IfNotPresent
lifecycle:
postStart:
exec:
command:
- echo "start"
preStop:
exec:
command:
- sleep 30
livenessProbe:
failureThreshold: 2
initialDelaySeconds: 30
periodSeconds: 10
successThreshold: 1
tcpSocket:
port: 8080
timeoutSeconds: 2
name: test-yaml
ports:
- containerPort: 8080
name: web
protocol: TCP
readinessProbe:
failureThreshold: 2
httpGet:
httpHeaders:
- name: a
value: b
path: /
port: 8080
scheme: HTTP
initialDelaySeconds: 30
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 2
resources:
limits:
cpu: 493m
memory: 622Mi
requests:
cpu: 10m
memory: 10Mi
securityContext:
allowPrivilegeEscalation: false
capabilities: {}
privileged: false
procMount: Default
readOnlyRootFilesystem: false
runAsNonRoot: false
volumeMounts:
- mountPath: /usr/share/zoneinfo/Asia/Shanghai
name: tz-config
- mountPath: /etc/localtime
name: tz-config
- mountPath: /etc/timezone
name: timezone
- mountPath: /mnt
name: nfs-test
dnsPolicy: ClusterFirst
initContainers:
- args:
- init
command:
- echo
env:
- name: TZ
value: Asia/Shanghai
- name: LANG
value: C.UTF-8
image: nignx-init
imagePullPolicy: Always
name: init
resources:
limits:
cpu: 351m
memory: 258Mi
requests:
cpu: 10m
memory: 10Mi
securityContext:
allowPrivilegeEscalation: false
capabilities: {}
privileged: false
procMount: Default
readOnlyRootFilesystem: false
runAsNonRoot: false
volumeMounts:
- mountPath: /usr/share/zoneinfo/Asia/Shanghai
name: tz-config
- mountPath: /etc/localtime
name: tz-config
- mountPath: /etc/timezone
name: timezone
nodeSelector:
ratel: "true"
restartPolicy: Always
securityContext:
sysctls:
- name: net.core.somaxconn
value: "16384"
- name: net.ipv4.tcp_max_syn_backlog
value: "16384"
tolerations:
- effect: NoSchedule
key: node-role.kubernetes.io/master
operator: Exists
volumes:
- name: projected-test
projected:
defaultMode: 420
sources:
- downwardAPI:
items:
- fieldRef:
fieldPath: metadata.name
path: /opt/x
- hostPath:
path: /usr/share/zoneinfo/Asia/Shanghai
type: ""
name: tz-config
- hostPath:
path: /etc/timezone
type: ""
name: timezone
- name: nfs-test
nfs:
path: /data/nfs
server: 1.1.1.1
status: {}
這個yaml比之前的稍複雜，並且添加了一些高階配置，手動編寫的還是比較麻煩的，所以用Ratel自動生成還是比較方便的，並且不會出錯。
3. 其他資原始檔自動生成
目前支援了很多資原始檔的自動生成，比如：Deployment、StatefulSet、DaemonSet、Service、Ingress、CronJob、Secret、ConfigMap、PV、PVC等，可以大大減少我們的工作量和k8s的複雜度。
如果想要系統的學習k8s，可以專注下k8s的課程：