Kubernetes共享挂载点问题

Question

我有一个包含logrotate和nginx容器的Pod：

apiVersion: v1
kind: Pod
metadata:
  name: nginx-log
  labels:
    app: nginx-log

spec:
  containers:

  - name: logrotate
    image: path/to/logrotate:latest
    volumeMounts:
    - name: logs
      mountPath: /var/log

  - name: nginx
    image: nginx:latest
    ports:
    - containerPort: 80
    volumeMounts:
    - name: logs
      mountPath: /var/log/nginx

  volumes:
  - name: logs
    emptyDir: {}

我的问题是nginx的日志是/var/ mountPath还是/var/log/ nginx，logrotate容器总是在/var/log/中看到nginx日志，而不是/var/log/nginx/。有没有可能强制nginx在emptyDir中创建nginx/文件夹并在那里登录？

Answer 1

我认为在Pod完全部署之前，Init Containers是一个很好的选择，它可以用来运行任务。

示例如下所示：

apiVersion: v1  
kind: Pod  
metadata:  
  name: nginx-log  
spec:  
  containers:

  - name: logrotate
    image: path/to/logrotate:latest
    volumeMounts:
    - name: logs
      mountPath: /var/log

  - name: nginx  
    image: nginx:latest  
    ports:
    - containerPort: 80    
    volumeMounts:  
    - name: logs  
      mountPath: /var/log/nginx  

  initContainers:  
  - name: logs  
    image: busybox  
    command: ["mkdir","-p","/var/log/nginx"]  
    volumeMounts:  
    - name: logs  
      mountPath: /var/log/nginx 

  volumes:
  - name: logs
    emptyDir: {}

您还可以阅读Using InitContainers to pre-populate Volume data in Kubernetes

Answer 2

好的，我已经让它工作了：

apiVersion: v1
kind: Pod
metadata:
  name: nginx-log
  labels:
    app: nginx-log

spec:
  containers:

  - name: logrotate
    image: path/to/image/logrotate:latest
    volumeMounts:
    - name: logs
      mountPath: /var/log

  - name: nginx
    image: nginx:latest
    ports:
    - containerPort: 80
    volumeMounts:
    - name: logs
      mountPath: /var/log/nginx
      subPath: nginx

  volumes:
  - name: logs
    emptyDir: {}

Logrotate side car取自：https://github.com/honestbee

在logrotate.tpl.conf中做了一些小的修改：

${LOGROTATE_PATTERN1} 
${LOGROTATE_PATTERN2}
{
    rotate ${LOGROTATE_ROTATE}
    ${LOGROTATE_MODE}
    size ${LOGROTATE_SIZE}
    missingok
    nocompress
    su root root
 }

在Dockerfile中：

FROM alpine:3.8

ENV CRON_SCHEDULE='*/30 * * * *' \
    LOGROTATE_SIZE='10M' \
    LOGROTATE_MODE='copytruncate' \
    LOGROTATE_PATTERN1='/var/log/*.log' \
    LOGROTATE_PATTERN2='/var/log/*/*.log' \
    LOGROTATE_ROTATE='5'

RUN apk --no-cache add logrotate tini gettext libintl \
    && mkdir -p /var/log \
    && chmod 775 /var/log \
    && mkdir -p /etc/logrotate.d

COPY logrotate.tpl.conf /logrotate.tpl.conf
COPY entrypoint.sh /usr/local/bin/entrypoint.sh

ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]

CMD ["/usr/sbin/crond", "-f", "-L", "/dev/stdout"]