kubernetes -- helm charts 开发: 6、 调试容器中python项目源码

以ceilometer-api为例，介绍调试的整个过程

1 修改容器的启动方式

将直接启动容器的方式改为不启动，自己进入容器后手动执行命令启动容器
以ceilometer-api为例，修改ceilometer-api这个deployment,具体执行如下命令:
先备份ceilometer-api这个deployment,即执行如下命令:
kubectl get deploy -n openstack ceilometer-api -oyaml > ceilometer-api.yaml

然后修改ceilomeyer-api的启动方式:
kubectl edit deploy -n openstack ceilometer-api 

可以看到如下内容:
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "6"
  creationTimestamp: 2019-01-10T14:05:15Z
  generation: 6
  labels:
    application: ceilometer
    component: api
    release_group: ceilometer
  name: ceilometer-api
  namespace: openstack
  resourceVersion: "3704244"
  selfLink: /apis/extensions/v1beta1/namespaces/openstack/deployments/ceilometer-api
  uid: c13d6a4c-14e0-11e9-8623-fa163edc2997
spec:
  progressDeadlineSeconds: 600
  replicas: 3
  revisionHistoryLimit: 3
  selector:
    matchLabels:
      application: ceilometer
      component: api
      release_group: ceilometer
  strategy:
    rollingUpdate:
      maxSurge: 3
      maxUnavailable: 1
    type: RollingUpdate
  template:
    metadata:
      annotations:
        configmap-bin-hash: d2eb483473276e7aab27e7b639c4edc3bb0e60125f67b8fbe4b90c149e9744f1
        configmap-etc-hash: f3303568db665b281aaf92fe22b55282ade57ffe0e5e61784e73c27ff38222d0
      creationTimestamp: null
      labels:
        application: ceilometer
        component: api
        release_group: ceilometer
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: release_group
                operator: In
                values:
                - ceilometer
              - key: application
                operator: In
                values:
                - ceilometer
              - key: component
                operator: In
                values:
                - api
            topologyKey: kubernetes.io/hostname
      containers:
      - command:
        - /tmp/ceilometer-api.sh
        - start
        image: hub.easystack.io/production/escloud-linux-source-ceilometer-api:5.0.1-3-beta82
        imagePullPolicy: IfNotPresent
        lifecycle:
          preStop:
            exec:
              command:
              - /tmp/ceilometer-api.sh
              - stop
        name: ceilometer-api
        ports:
        - containerPort: 8777
          name: ce-api
          protocol: TCP
        readinessProbe:
          failureThreshold: 3
          periodSeconds: 10
          successThreshold: 1
          tcpSocket:
            port: 8777
          timeoutSeconds: 1
        resources:
          limits:
            cpu: "2"
            memory: 1Gi
          requests:
            cpu: 100m
            memory: 124Mi
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
        volumeMounts:
        - mountPath: /etc/ceilometer
          name: pod-etc-ceilometer
        - mountPath: /etc/ceilometer/ceilometer.conf
          name: ceilometer-etc
          readOnly: true
          subPath: ceilometer.conf
        - mountPath: /etc/ceilometer/api_paste.ini
          name: ceilometer-etc
          readOnly: true
          subPath: api_paste.ini
        - mountPath: /etc/ceilometer/policy.json
          name: ceilometer-etc
          readOnly: true
          subPath: policy.json
        - mountPath: /etc/ceilometer/event_definitions.yaml
          name: ceilometer-etc
          readOnly: true
          subPath: event_definitions.yaml
        - mountPath: /etc/ceilometer/event_pipeline.yaml
          name: ceilometer-etc
          readOnly: true
          subPath: event_pipeline.yaml
        - mountPath: /etc/ceilometer/pipeline.yaml
          name: ceilometer-etc
          readOnly: true
          subPath: pipeline.yaml
        - mountPath: /etc/ceilometer/gnocchi_resources.yaml
          name: ceilometer-etc
          readOnly: true
          subPath: gnocchi_resources.yaml
        - mountPath: /etc/httpd/conf.d/wsgi-ceilometer.conf
          name: ceilometer-etc
          readOnly: true
          subPath: wsgi-ceilometer.conf
        - mountPath: /etc/ceilometer/mapping.json
          name: ceilometer-etc
          readOnly: true
          subPath: mapping.json
        - mountPath: /tmp/ceilometer-api.sh
          name: ceilometer-bin
          readOnly: true
          subPath: ceilometer-api.sh
      dnsPolicy: ClusterFirst
      initContainers:
      - command:
        - kubernetes-entrypoint
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              apiVersion: v1
              fieldPath: metadata.name
        - name: NAMESPACE
          valueFrom:
            fieldRef:
              apiVersion: v1
              fieldPath: metadata.namespace
        - name: INTERFACE_NAME
          value: eth0
        - name: DEPENDENCY_SERVICE
          value: openstack:keystone-api,openstack:mariadb,openstack:mongodb
        - name: DEPENDENCY_JOBS
          value: ceilometer-db-init-mongodb,ceilometer-db-sync,ceilometer-ks-user,ceilometer-ks-endpoints
        - name: DEPENDENCY_DAEMONSET
        - name: DEPENDENCY_CONTAINER
        - name: COMMAND
          value: echo done
        image: hub.easystack.io/production/kubernetes-entrypoint:v0.2.1
        imagePullPolicy: IfNotPresent
        name: init
        resources: {}
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      nodeSelector:
        openstack-control-plane: enabled
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 600
      volumes:
      - emptyDir: {}
        name: pod-etc-ceilometer
      - configMap:
          defaultMode: 292
          name: ceilometer-etc
        name: ceilometer-etc
      - configMap:
          defaultMode: 365
          name: ceilometer-bin
        name: ceilometer-bin
status:
  availableReplicas: 3
  conditions:
  - lastTransitionTime: 2019-01-21T06:56:00Z
    lastUpdateTime: 2019-01-21T06:56:00Z
    message: Deployment has minimum availability.
    reason: MinimumReplicasAvailable
    status: "True"
    type: Available
  - lastTransitionTime: 2019-01-10T14:21:48Z
    lastUpdateTime: 2019-01-22T04:34:58Z
    message: ReplicaSet "ceilometer-api-546b888f69" has successfully progressed.
    reason: NewReplicaSetAvailable
    status: "True"
    type: Progressing
  observedGeneration: 6
  readyReplicas: 3
  replicas: 3
  updatedReplicas: 3

找到command这一行的内容，具体如下:
      containers:
      - command:
        - /tmp/ceilometer-api.sh
        - start
        image: hub.easystack.io/production/escloud-linux-source-ceilometer-api:5.0.1-3-beta82

修改为:
      containers:
      - command:
        - sleep
        - 3d
        image: hub.easystack.io/production/escloud-linux-source-ceilometer-api:5.0.1-3-beta82

即将容器的启动命令，从
        - /tmp/ceilometer-api.sh
        - start
修改为:
        - sleep
        - 3d
表示容器启动时会执行: sleep 3d这个休眠3天的命令，这样就表示容器启动后不会开启ceilometer-api服务

2 将要调试的源码拷贝到容器中

kubectl cp -n :/root
注意:
请将  替换为待调试的文件名称
请将 替换为该pod所在的命名空间
请将 替换为pod的真实名称
请将 /root 替换为需要调试的源码位置，通常是: /usr/lib/python2.7/site-packages 下面待调试的python项目中对应位置的文件所在目录

3 进入容器

以ceilometer-api为例，进入ceilometer-api这个pod
即执行如下命令:
kubectl exec -it -n /bin/bash

请将:  替换为步骤2中将源码拷贝到的pod名称

然后进入到步骤2刚才拷贝的待调试源码所在位置，找到拷贝到容器中需要调试的python文件，
在待调试位置加上:
import pdb;pdb.set_trace()
即可

4 手动启动容器中的服务

找到原先容器启动命令执行的脚本
以ceilometer-api为例，
根据步骤1中原先ceilometer-api容器中启动的脚本命令是:
        - /tmp/ceilometer-api.sh
        - start
因此，可以确认启动容器的脚本文件为:
/tmp/ceilometer-api.sh
查看该脚本文件内容如下:
cat /tmp/ceilometer-api.sh
结果如下:
#!/usr/local/bin/dumb-init /bin/bash

set -ex
COMMAND="${@:-start}"

function start () {
  exec httpd -DFOREGROUND
}

function stop () {
  # apachectl -k graceful-stop
  kill -TERM 1
}

$COMMAND

本来可以直接用这个命令:  exec httpd -DFOREGROUND
开启调试，由于这个开启针对ceilometer-api是以wsgi方式执行，不好调试，因此可以用
下面的方式调试:
由于ceilometer-api可以通过手动开启，即执行如下命令:
ceilometer-api --port 8777 

5 调试源码

容器中的服务被手动启动后，进入到自己刚才设置的断点处，此时即可进行调试