Kubernetes-如何读取写入Pod中而不是stdout/stderr的文件中的日志? [英] Kubernetes - How to read logs that are written to files in pods instead of stdout/stderr?

问题描述

我有一个状态为CrashLoopBackOff的吊舱，从kubectl logs <pod-name> -p中看到的日志仅显示了一部分.在其他文件(例如/var/log/something/something.log)中找到其他日志.

I have a pod in a state of CrashLoopBackOff, the logs I'm seeing from kubectl logs <pod-name> -p present only a partial picutre. Other logs are found in other files (e.g. /var/log/something/something.log).

由于此Pod崩溃了，所以我不能kubectl exec进入那里的外壳并查看文件.

Since this pod is crashed, I can't kubectl exec into a shell there and look at the files.

如何查看不再运行的容器产生的日志文件?

How can I look at the log files produced by a container that is no longer running?

更具体地说，我正在寻找$HOME/logs/es.log下的日志文件文件(在发生故障的容器中)

To be more specific, I'm looking for log files file under $HOME/logs/es.log (in the container that failed)

推荐答案

对于无法解决这个看似常见的问题，我感到非常沮丧，于是我构建了一个Docker镜像，将日志文件拖尾并将其发送到stdout，以用作边柜.

I was so frustrated from finding no solution to this seemingly common problem that I built a docker image that tails log files and sends them to stdout, to be used as a sidecar container.

这就是我所做的:

1. 我将带有emptyDir{}的卷添加到了豆荚中
2. 我将该卷安装到了我的主容器中，其中mountPath是它将日志写入到的目录
3. 我在Pod中添加了另一个容器，称为记录器"，该图像是我编写的日志跟踪器(lutraman/logger-sidecar:v2)，并将相同的卷装载到/logs中(我编写了脚本以从中读取日志此目录)

1. I added a volume with emptyDir{} to the pod
2. I mounted that volume to my main container, with the mountPath being the directory to which it writes the logs to
3. I added another container to the pod, called "logger", with the image being the log tracker I wrote (lutraman/logger-sidecar:v2), and mounted the same volume to /logs (I programmed the script to read the logs from this directory)

然后，所有写入该目录的日志都可以通过kubectl logs <pod-name> -c logger

then, all the logs written to that directory, can be accessed by kubectl logs <pod-name> -c logger

以下是一个示例yaml:

Here is an example yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: dummy
  labels:
    app: dummy
spec:
  selector:
    matchLabels:
      app: dummy
  template:
    metadata:
      labels:
        app: dummy
    spec:
      volumes:
        - name: logs
          emptyDir: {}
      containers:
        - name: dummy-app # the app that writes logs to files
          image: lutraman/dummy:v2
          ports:
            - containerPort: 8080
              name: http
              protocol: TCP
          env:
            - name: MESSAGE
              value: 'hello-test'
            - name: LOG_FILE
              value: '/var/log/app.log'
          volumeMounts:
            - name: logs
              mountPath: /var/log
        - name: logger # the sidecar container tracking logs and sending them to stdout
          image: lutraman/logger-sidecar:v2
          volumeMounts:
            - name: logs
              mountPath: /logs

---

对于任何有兴趣的人，这是我制作Sidecar容器的方式:

---

For anyone who is interested, here is how I made the sidecar container:

Dockerfile:

Dockerfile:

FROM alpine:3.9

RUN apk add bash --no-cache

COPY addTail /addTail
COPY logtrack.sh /logtrack.sh

CMD ["./logtrack.sh"]

addTail:

#!/bin/sh

(exec tail -F logs/$3 | sed "s/^/$3: /" ) &
echo $! >> /tmp/pids

logtrack.sh:

logtrack.sh:

#!/bin/bash

trap cleanup INT

function cleanup() {
  while read pid; do kill $pid; echo killed $pid; done < /tmp/pids
}

: > /tmp/pids

for log in $(ls logs); do
  ./addTail n logs $log
done

inotifyd ./addTail `pwd`/logs:n 

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