Question

我正在尝试创建docker映像，该映像将从root用户和定制用户执行cronjobs。到目前为止，只有root用户正在工作：

FROM amazonlinux:2017.09
RUN yum -y install ca-certificates shadow-utils cronie && yum -y clean all
# root cronjob
RUN echo '* * * * * echo "$USER - Working in a coal mine..." > /proc/1/fd/1 2>/proc/1/fd/2' > ~/cronjob
RUN chmod 0644 ~/cronjob
RUN crontab ~/cronjob
RUN useradd -ms /bin/bash ansible
# Ansible cronjob
USER ansible
RUN echo '* * * * * echo "$USER - Working in a coal mine..." > /proc/1/fd/1 2>/proc/1/fd/2' > ~/cronjob
RUN chmod 0644 ~/cronjob
RUN crontab ~/cronjob
USER root
CMD ["/usr/sbin/crond", "-n"]

我使用此命令docker build -t demotest -f Dockerfile .构建此docker 我使用此命令docker run -t -i demotest:latest

执行创建的图像

执行结果：

> docker run -t -i demotest:latest
root - Working in a coal mine...
root - Working in a coal mine...
root - Working in a coal mine...
root - Working in a coal mine...

一些细节：

docker run -t -i demotest:latest bash -c 'ls -l /home/ansible/cronjob'
-rw-r--r-- 1 ansible ansible 81 Jul 11 16:06 /home/ansible/cronjob

docker run -t -i demotest:latest bash -c 'ls -l /root/cronjob'
-rw-r--r-- 1 root root 81 Jul 11 16:06 /root/cronjob

docker run -t -i demotest:latest bash -c 'crontab -u root -l'
* * * * * echo "$USER - Working in a coal mine..." > /proc/1/fd/1 2>/proc/1/fd/2

docker run -t -i demotest:latest bash -c 'crontab -u ansible -l'
* * * * * echo "$USER - Working in a coal mine..." > /proc/1/fd/1 2>/proc/1/fd/2

我在做什么错了？

更新信息

我将CMD更改为：CMD ["/usr/sbin/crond", "-n", "-x", "sch"]

这生成了输出：

docker run -t -i demotest:latest
debug flags enabled: sch
[1] cron started
log_it: (CRON 1) INFO (RANDOM_DELAY will be scaled with factor 85% if used.)
log_it: (CRON 1) INFO (running with inotify support)
[1] GMToff=0
[1] Target time=1562865060, sec-to-wait=12
user [root:0:0:...] cmd="run-parts /etc/cron.hourly"
user [root:0:0:...] cmd="[ ! -f /etc/cron.hourly/0anacron ] && run-parts /etc/cron.monthly"
user [root:0:0:...] cmd="[ ! -f /etc/cron.hourly/0anacron ] && run-parts /etc/cron.weekly"
user [root:0:0:...] cmd="[ ! -f /etc/cron.hourly/0anacron ] && run-parts /etc/cron.daily"
user [ansible:500:500:...] cmd="echo "$USER - Working in a coal mine..." > /proc/1/fd/1 2>/proc/1/fd/2"
user [root:0:0:...] cmd="echo "$USER - Working in a coal mine..." > /proc/1/fd/1 2>/proc/1/fd/2"
Minute-ly job. Recording time 1562865061
[1] Target time=1562865120, sec-to-wait=60
Minute-ly job. Recording time 1562865061
log_it: (root 8) CMD (echo "$USER - Working in a coal mine..." > /proc/1/fd/1 2>/proc/1/fd/2)
log_it: (ansible 9) CMD (echo "$USER - Working in a coal mine..." > /proc/1/fd/1 2>/proc/1/fd/2)
root - Working in a coal mine...

这表明自定义用户cronjob已执行，但输出未重定向。因此问题变成了-如何正确将stdout重定向到主机控制台？

Answer 1

更改Dockerfile的最后一行：

来自

CMD ["/usr/sbin/crond", "-n", "-x", "sch"]

到

CMD ["cron", "-f"]

注意： cron -f-> cron前景

在Docker中执行用户Cron作业的问题

更新信息

1 个答案: