使用Helm簡化K8S應用管理

一、背景介紹

在使用純手工維護yaml文件方式完成內網開發和兩套測試環境和現網生成環境的核心微服務pod化之後。發現主要痛點如下：
1、工作負載相關的yaml文件維護量巨大，且易出錯。（目前內網共有77個工作負載）

2、研發人員對工作負載配置改動的需求比較頻繁，例如修改jvm相關參數，增加initcontainer、修改liveness、readiness探針、親和性與反親和性配置等，這類的配置嚴重同質化。

3、每個namespace都存在環境變量、configmap、rbac、pv\pvc解耦類的配置，如果對應的配置未提前創建，則後續創建的工作負載無法正常工作。

隨着第二階段各平臺模塊的微服務化改造工作的推進，預計每個namespace會分別增加30-40個工作負載，因此需要維護的yaml文件將急劇擴展，手工維護已不現實。因此使用helm來維護k8s應用被提上議事日程。
關於helm的配置文件語法及服務端配置請參考官網手冊：https://helm.sh/docs/

二、需求分析

1、公共配置類
Configmap

每個namespace至少有兩個configmap，其中center-config存儲了各個環境的mysql、mongodb、redis等基礎公共服務的IP、用戶名和密碼、連接池配置信息等，我們通過集中配置解耦做到代碼編譯一次鏡像，各個環境都能運行。
hb-lan-server-xml文件實際上就是tomcat下面的server.xml文件，由於早前代碼上使用redis做登陸session，需要修改server.xml，因此需要對這個文件做解耦配置，後續創建的工作負載通過外掛的形式替換鏡像層中的server.xml文件。


Secret
每個namespace都會存在harborsecret的token，顧名思義就是harbor倉庫拉取鏡像使用的權限信息，否則創建工作負載的時候會無法拉取鏡像。

pv\pvc
每個namespace都有一個配套共享存儲，用來統一存放用戶上傳的附件資源，內網環境我們通過nfs來實現。

rbac相關
因爲應用程序會通過curl k8s的master來獲取一些配置類的信息，如果沒有做相應的rbac授權，訪問會出現401，因此需要對每個namespace下的default sa用戶做rbac授權。

2、工作負載類

工作負載目前統一爲無狀態工作負載，主要分爲兩類，一類需要對外暴露域名和端口，另一類程序內部通過zk進行dubbo調用

三、配置helm與測試

1、公共配置類

# helm create basic
# cd basic
# helm create namespace
# rm -rf charts/namespace/templates/*

# cat charts/namespace/values.yaml 
# Default values for namespace.
# This is a YAML-formatted file.
# Declare variables to be passed into your templates.

namespace: default

# cat charts/namespace/templates/namespace.yaml 
apiVersion: v1
kind: Namespace
metadata:
 name: {{ .Values.namespace }}

# cat charts/namespace/templates/env-confgimap.yaml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: center-config
  namespace: {{ .Values.namespace }}
  labels:
    app: {{ .Release.Name }}
data:
  ES_CLUSTER_NAME: hbjy6_dev
  ES_CLUSTER_NODES: 192.168.1.19:9500
  ETCD_ENDPOINTS: https://192.168.1.11:2379,https://192.168.1.17:2379,https://192.168.1.23:2379
  ETCD_PASSWORD: ""
  ETCD_SSL_KEY: ""
  ETCD_SSL_KEY_FILE: /mnt/mfs/private/etcd/client-key.pem
  ETCD_SSL_KEYCERT: ""
  ETCD_SSL_KEYCERT_FILE: /mnt/mfs/private/etcd/client.pem
  ETCD_SSL_TRUSTCERT: ""
  ETCD_SSL_TRUSTCERT_FILE: /mnt/mfs/private/etcd/ca.pem
  ETCD_USER: ""
  MONGODB_PASSWORD: xxxx
  MONGODB_REPLICA_SET: 192.168.1.21:37017,192.168.1.15:57017,192.168.1.16:57017
  MONGODB_USER: ROOT
  MYSQL_MASTER_PASSWORD: "xxxxx"
  MYSQL_MASTER_URL: 192.168.1.20:3306
  MYSQL_MASTER_USER: root
  MYSQL_PROXYSQL_PASSWORD: "xxxxx"
  MYSQL_PROXYSQL_URL: 192.168.1.20:1234
  MYSQL_PROXYSQL_USER: root
  REDIS_MASTER_NAME: sigma-server1
  REDIS_PASSWORD: "xxxxx"
  REDIS_SENTINEL1_HOST: 192.168.1.20
  REDIS_SENTINEL1_PORT: "26379"
  REDIS_SENTINEL2_HOST: 192.168.1.21
  REDIS_SENTINEL2_PORT: "26379"
  REDIS_SENTINEL3_HOST: 192.168.1.22
  REDIS_SENTINEL3_PORT: "26379"
  ROCKETMQ_NAMESERVER: 192.168.1.20:9876
  ZK_BUSINESS_ADDRESS: 192.168.1.20:2181,192.168.1.21:2181,192.168.1.22:2181
  ZK_REGISTRY_ADDRESS: 192.168.1.20:2181,192.168.1.21:2181,192.168.1.22:2181

# cat charts/namespace/templates/secret.yaml 
apiVersion: v1
kind: Secret
metadata:
  name: harborsecret
  namespace: {{ .Values.namespace }}
type: kubernetes.io/dockerconfigjson
data:
  .dockerconfigjson:eyJhdXRocyI6eyJoYXJib3IuNTlpZWR1LmNvbSI6eyJ1c2VybmFtZSI6ImFkbWluIiwicGFzc3dvcmQiOiJIYXJib3IxMjM0NSIsImF1dGgiOiJZV1J0YVc0NlNHRnlZbTl5TVRJek5EVT0ifX19

# cat charts/namespace/templates/mfsdata-pv-pvc.yaml 
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mfsdata-{{ .Values.namespace }}
spec:
  capacity:
    storage: 150Gi 
  accessModes:
  - ReadWriteMany 
  nfs: 
    path: /mnt/mfs
    server: 192.168.1.20
  persistentVolumeReclaimPolicy: Retain
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: mfsdata-{{ .Values.namespace }}
  namespace: {{ .Values.namespace }}
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 150Gi

# cat charts/namespace/templates/clusterrole.yaml 
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: {{ .Release.Name }}-{{ .Values.namespace }}-role
  labels:
    app: {{ .Release.Name }}
rules:
- apiGroups: [""]
  resources: ["*"]
  verbs: ["get","watch","list" ]
- apiGroups: ["storage.k8s.io"]
  resources: ["*"]
  verbs: ["get","watch","list" ]
- apiGroups: ["rbac.authorization.k8s.io"]
  resources: ["*"]
  verbs: ["get","watch","list" ]
- apiGroups: ["batch"]
  resources: ["*"]
  verbs: ["get","watch","list" ]
- apiGroups: ["apps"]
  resources: ["*"]
  verbs: ["get","watch","list" ]
- apiGroups: ["extensions"]
  resources: ["*"]
  verbs: ["get","watch","list" ]

# cat charts/namespace/templates/clusterrolebinding.yaml 
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: {{ .Release.Name }}-{{ .Values.namespace }}-binding
  labels:
    app: {{ .Release.Name }}
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: {{ .Release.Name }}-{{ .Values.namespace }}-role
subjects:
- kind: ServiceAccount
  name: default
  namespace: {{ .Values.namespace }}

2、工作負載類

# cd basic
# helm create tomcat
# rm -rf charts/namespace/tomcat/*

# cat charts/tomcat/values.yaml   
# Default values for tomcat.
# This is a YAML-formatted file.
# Declare variables to be passed into your templates.

replicaCount: 1
version: v1
mfsdata: mfsdata
env:
  -server -Xms1024M -Xmx1024M -XX:MaxMetaspaceSize=320m -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/home/tomcat/jvmdump/
  -Duser.timezone=Asia/Shanghai
  -Drocketmq.client.logRoot=/home/tomcat/logs/rocketmqlog 

image: repository: harbor.59iedu.com
pullPolicy: Always

service:
  type: ClusterIP
  port: 8080
  dubboport: 20880

ingress:
  enabled: false
  annotations: 
    nginx.ingress.kubernetes.io/rewrite-target: /
  path: /
  hosts:
    - www.test1.com
    - www.test2.com

resources: 
  # We usually recommend not to specify default resources and to leave this as a conscious
  # choice for the user. This also increases chances charts run on environments with little
  # resources, such as Minikube. If you do want to specify resources, uncomment the following
  # lines, adjust them as necessary, and remove the curly braces after 'resources:'.
   limits:
    cpu: 200m
    memory: 0.2Gi
   requests:
    cpu: 100m
    memory: 0.1Gi

nodeSelector: {}

tolerations:
        - key: node.kubernetes.io/not-ready
          operator: Exists
          effect: NoExecute
          tolerationSeconds: 300
        - key: node.kubernetes.io/unreachable
          operator: Exists
          effect: NoExecute
          tolerationSeconds: 300

affinity: 
       schedulerName: default-scheduler

# cat charts/tomcat/templates/deployment.yaml 
{{- $releaseName := .Release.Name -}}
apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: {{ .Release.Name }}
  namespace: {{ .Values.namespace }}
  labels:
    app: {{ .Values.namespace }}
    version: {{ .Values.version }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app: {{ .Release.Name  }}
      version: {{ .Values.version }}
  template:
    metadata:
      labels:
        app: {{ .Release.Name }}
        version: {{ .Values.version }}
    strategy:
     type: RollingUpdate
     rollingUpdate:
       maxUnavailable: 25%
       maxSurge: 25%
    revisionHistoryLimit: 10
    progressDeadlineSeconds: 600
    spec:
      volumes:
        - name: hb-lan-server-xml
          configMap:
           name: hb-lan-server-xml
           items:
             - key: server.xml
               path: server.xml

        - name: vol-localtime
          hostPath:
            path: /etc/localtime
            type: ''
        - name: mfsdata
          persistentVolumeClaim:
            claimName: {{ .Values.mfsdata }}
        - name: pp-agent
          emptyDir: {}

      imagePullSecrets:
       - name: harborsecret

      initContainers:
        - name: init-pinpoint
          image: 'harbor.59iedu.com/fjhb/pp_agent:latest'
          command:
            - sh
            - '-c'
            - cp -rp /var/lib/pp_agent/* /var/init/pinpoint
          resources: {}
          volumeMounts:
            - name: pp-agent
              mountPath: /var/init/pinpoint
          terminationMessagePath: /dev/termination-log
          terminationMessagePolicy: File
          imagePullPolicy: Always

      containers:
        - name: {{ .Release.Name }}
          image: {{ .Values.image }}
          imagePullPolicy: {{ .Values.pullPolicy }}
          terminationGracePeriodSeconds: 30
          dnsPolicy: ClusterFirst
          securityContext: {}
          lifecycle:
           preStop:
            exec:
             command: ["/bin/bash", "-c", "PID=`pidof java` && kill -SIGTERM $PID && while ps -p $PID > /dev/null; do sleep 1; done;"]

          envFrom:
          - configMapRef:
               name: center-config
          env:
            - name: POD_IP
              valueFrom:
                fieldRef:
                  fieldPath: status.podIP
            - name: CATALINA_OPTS
              value: >-
                -javaagent:/var/init/pinpoint/pinpoint-bootstrap.jar
                -Dpinpoint.agentId=${POD_IP}
                -Dpinpoint.applicationName=test1-{{ .Release.Name }}
            - name: JAVA_OPTS
              value: >- 
                {{ .Values.env }}
          ports:
            - name: http
              containerPort: {{ .Values.service.port }}
              protocol: TCP
          livenessProbe:
            tcpSocket:
              port: {{ .Values.service.port }}
            initialDelaySeconds: 60
            timeoutSeconds: 2
            periodSeconds: 10
            successThreshold: 1
            failureThreshold: 3
          readinessProbe:
            tcpSocket:
              port: {{ .Values.service.dubboport }}
            initialDelaySeconds: 120
            timeoutSeconds: 3
            periodSeconds: 10
            successThreshold: 1
            failureThreshold: 3
          volumeMounts:
            - name: hb-lan-server-xml 
              mountPath: /home/tomcat/conf/server.xml
              subPath: server.xml
            - name: vol-localtime
              readOnly: true
              mountPath: /etc/localtime
            - name: mfsdata
              mountPath: /mnt/mfs
            - name: pp-agent
              mountPath: /var/init/pinpoint
          resources:
{{ toYaml .Values.resources | indent 12 }}
    {{- with .Values.nodeSelector }}
      nodeSelector:
{{ toYaml . | indent 8 }}
    {{- end }}
    {{- with .Values.affinity }}
      affinity:
        podAntiAffinity:
          PreferredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: app
                operator: In
                values:
                - {{ $releaseName }}
            topologyKey: "kubernetes.io/hostname"
{{ toYaml . | indent 8 }}
    {{- end }}
    {{- with .Values.tolerations }}
      tolerations:
{{ toYaml . | indent 8 }}
    {{- end }}

# cat charts/tomcat/templates/ingress.yaml 
{{- if .Values.ingress.enabled -}}
{{- $servicePort := .Values.service.port -}}
{{- $ingressPath := .Values.ingress.path -}}
{{- $releaseName := .Release.Name -}}
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: {{ .Release.Name }}
  namespace: {{ .Values.namespace }}
  labels:
    app: {{ .Release.Name }}
    version: {{ .Values.version }}
{{- with .Values.ingress.annotations }}
  annotations:
{{ toYaml . | indent 4 }}
{{- end }}
spec:
{{- if .Values.ingress.tls }}
  tls:
  {{- range .Values.ingress.tls }}
    - hosts:
      {{- range .hosts }}
        - {{ . }}
      {{- end }}
      secretName: {{ .secretName }}
  {{- end }}
{{- end }}
  rules:
  {{- range .Values.ingress.hosts }}
    - host: {{ . }}
      http:
        paths:
          - path: {{ $ingressPath }}
            backend:
              serviceName: {{ $releaseName }}
              servicePort: {{ $servicePort }}
  {{- end }}
{{- end }}

# cat charts/tomcat/templates/service.yaml 
apiVersion: v1
kind: Service
metadata:
  name: {{ .Release.Name  }}
  namespace: {{ .Values.namespace }}
  labels:
    app: {{ .Release.Name  }}
    version: {{ .Values.version }}
spec:
  type: {{ .Values.service.type }}
  ports:
    - port: {{ .Values.service.port }}
      targetPort: http
      protocol: TCP
      name: http
  selector:
    app: {{ .Release.Name  }}
    version: {{ .Values.version }}

3、運行測試

# helm install --debug --dry-run /root/basic/charts/namespace/  \
--set namespace=test3

# helm install --debug --dry-run /root/basic/charts/tomcat/   \
--name tomcat-test \
--set namespace=test3  \
--set mfsdata=mfsdata-test3 \
--set replicaCount=2 \
--set image=harbor.59iedu.com/dev/tomcat_base:v1.1-20181127 \
--set ingress.enabled=true \
--set ingress.hosts={tomcat.59iedu.com} \
--set resources.limits.cpu=2000m \
--set resources.limits.memory=2Gi \
--set resources.requests.cpu=500m \
--set resources.requests.memory=1Gi \
--set service.dubboport=8080

4、創建release

# helm install  /root/basic/charts/namespace/ --set namespace=test3

# helm install  /root/basic/charts/tomcat/   \
--name tomcat-test \
--set namespace=test3  \
--set mfsdata=mfsdata-test3 \
--set replicaCount=2 \
--set image=harbor.59iedu.com/dev/tomcat_base:v1.1-20181127 \
--set ingress.enabled=true \
--set ingress.hosts={tomcat.59iedu.com} \
--set resources.limits.cpu=2000m \
--set resources.limits.memory=2Gi \
--set resources.requests.cpu=500m \
--set resources.requests.memory=1Gi \
--set service.dubboport=8080

四、更新與回滾

# helm upgrade --install tomcat-test \
--values /root/basic/charts/tomcat/values.yaml   \
--set namespace=test3  \
--set mfsdata=mfsdata-test3 \
--set replicaCount=1 \
--set image=harbor.59iedu.com/dev/tomcat_base:v1.1-20181127 \
--set ingress.enabled=true \
--set ingress.hosts={tomcat1.59iedu.com} \
--set resources.limits.cpu=200m \
--set resources.limits.memory=1Gi \
--set resources.requests.cpu=100m \
--set resources.requests.memory=0.5Gi \
--set service.dubboport=8080 \
/root/basic/charts/tomcat

萬一更新失敗，可選擇回滾

# helm rollback tomcat-test 1  
# helm history tomcat-test 
# helm get --revision 1 tomcat-test