将 sidecar 容器日志拖尾到现有 pod

Question

我正在尝试将边车容器添加到现有 pod (webapp-1) 以保存日志。但是，创建 Pod 后出现错误。 pod 崩溃，状态变为错误..

对于下面的问题我添加了yaml文件。如果可以，请告诉我。

 给运行 pod logging-pod添加side car容器，blow规范

 sidecar容器镜像为busybox，容器写入日志如下

tail -n+1 /var/log/k8slog/application.log

 容器与挂载到

的应用程序容器共享卷日志

目录/var/log/k8slog

 不要更改应用程序容器并验证日志是否已正确写入文件

这是yaml文件..我不明白我在哪里犯了错误

apiVersion: v1

kind: Pod

metadata:

  creationTimestamp: "2021-10-25T07:54:07Z"

  labels:

    name: webapp-1

  name: webapp-1

  namespace: default

  resourceVersion: "3241"

  uid: 8cc29748-7879-4726-ac60-497ee41f7bd6

spec:

  containers:

  - image: kodekloud/event-simulator

    imagePullPolicy: Always

    name: simple-webapp

    - /bin/sh

    - -c

    - >

      i=0;

      while true;

      do

        echo "$i: $(date)" >> /var/log/k8slog/application.log

        echo "$(date) INFO $i" >>;

        i=$((i+1));

       sleep 1;

      done

    volumeMounts:

    - name: varlog

      mountPath: /var/log

  - name: count-log-1

    image: busybox

    args: [/bin/sh, -c, 'tail -n+1 /var/log/k8slog/application.log']

    volumeMounts:

    - name: varlog

      mountPath: /var/log

    ports:

    - containerPort: 8080

      protocol: TCP

    resources: {}

    terminationMessagePath: /dev/termination-log

    terminationMessagePolicy: File

    volumeMounts:

    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount

      name: default-token-fgstk

      readOnly: true

  dnsPolicy: ClusterFirst

  enableServiceLinks: true

  nodeName: controlplane

  preemptionPolicy: PreemptLowerPriority

  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: varlog

    mountPath: /var/log

  - name: default-token-fgstk

    secret:

      defaultMode: 420

      secretName: default-token-fgstk

status:

  conditions:

  - lastProbeTime: null

    lastTransitionTime: "2021-10-25T07:54:07Z"

    status: "True"

    type: Initialized

  - lastProbeTime: null

Answer 1

首先，您可以创建目录和日志文件本身。如果 count-log-1 容器首先启动，它将没有任何内容可读取并退出并出错。为此，一个好的做法是使用 Init Container。 https://kubernetes.io/docs/concepts/workloads/pods/init-containers/

其次，容器需要有一个共享卷，日志文件将存在于该共享卷上。如果不需要持久化数据，一个 emptyDir 卷就足够了。 https://kubernetes.io/docs/concepts/workloads/pods/init-containers/

最后，您在 shell 命令中出现了一些错误。完整 .yaml 个文件：

apiVersion: v1
kind: Pod
metadata:
  labels:
    name: webapp-1
  name: webapp-1
  namespace: default

spec:
# Init container fo creating the log directory and file
# on the emptyDir volume, which will be passed to the containers
  initContainers:
  - name: create-log-file
    image: busybox
    command:
      - sh 
      - -c
      - |
          #!/bin/sh
          mkdir -p /var/log/k8slog
          touch /var/log/k8slog/application.log
# Mount varlog volume to the Init container
    volumeMounts:
    - name: varlog
      mountPath: /var/log

  containers:
  - image: kodekloud/event-simulator
    imagePullPolicy: Always
    name: simple-webapp
    command:
      - sh
      - -c
      - |
          i=0
          while true; do
            echo "$i: $(date)" >> /var/log/k8slog/application.log
            echo "$(date) INFO $i"
            i=$((i+1))
          sleep 1
          done
# Mount varlog volume to simple-webapp container
    volumeMounts:
    - name: varlog
      mountPath: /var/log
  - name: count-log-1
    image: busybox
    command:
      - sh
      - -c
      - |
          tail -f -n 1 /var/log/k8slog/application.log
# Mount varlog volume to count-log-1 container
    volumeMounts:
    - name: varlog
      mountPath: /var/log

# Define na emptyDir shared volume
  volumes:
  - name: varlog
    emptyDir: {}

将 sidecar 容器日志拖尾到现有 pod

Tailing sidecar container logs to an existing pod

logging

kubernetes

sidecar