问题描述
我正在使用普通的postgresql：alpine泊坞映像，但是必须每天计划数据库备份。我认为这是一个很普通的任务。
I am using the "plain" postgresql:alpine docker image, but have to schedule a database backup daily. I think this is a pretty common task.
我创建了一个脚本 backup 并存储在 / etc / periodic / 15min ，并使其可执行：
I created a script backupand stored in the container in /etc/periodic/15min, and made it executable:
bash-4.4# ls -l /etc/periodic/15min/
total 4
-rwxr-xr-x 1 root root 95 Mar 2 15:44 backup
我尝试手动执行它，效果很好。
I tried executing it manually, that works fine.
我的问题是让 crond 自动运行。
My problem is getting crond to run automatically.
如果我执行 docker exec my-postgresql-container crond ，将启动守护进程并执行cron，但是我想将其嵌入到我的Dockerfile中
If I exec docker exec my-postgresql-container crond, the deamon is started and cron works, but I would like to embed this into my Dockerfile
FROM postgres:alpine
# my backup script, MUST NOT have .sh extension
COPY backup.sh /etc/periodic/15min/backup
RUN chmod a+x /etc/periodic/15min/backup
RUN crond # <- doesn't work
我不知道如何在官方中重写或覆盖命令图片。出于更新原因，如果可能的话，我也希望保留在这些图像上。
I have no idea how to rewrite or overwrite the commands in the official image. For update reasons I also would like to stay on these images, if possible.
推荐答案
安装其中将使您能够运行 crond 和 postgresql 。 Dockerfile 将如下所示：
Install Supervisord which will makes you able to run crond and postgresql. The Dockerfile will be as the following:
FROM postgres:alpine
RUN apk add --no-cache supervisor
RUN mkdir /etc/supervisor.d
COPY postgres_cron.ini /etc/supervisor.d/postgres_cron.ini
ENTRYPOINT ["/usr/bin/supervisord", "-c", "/etc/supervisord.conf"]
而 postgres_cron.ini 将如下所示：
[supervisord]
logfile=/var/log/supervisord.log ; (main log file;default $CWD/supervisord.log)
loglevel=info ; (log level;default info; others: debug,warn,trace)
nodaemon=true ; (start in foreground if true;default false)
[program:postgres]
command=/usr/local/bin/docker-entrypoint.sh postgres
autostart=true
autorestart=true
[program:cron]
command =/usr/sbin/crond -f
autostart=true
autorestart=true
然后，您可以启动docker构建过程并从新映像运行容器。随时根据需要修改 Dockerfile 或 postgres_cron.ini
Then you can start the docker build process and run a container from your new image. Feel free to modify the Dockerfile or postgres_cron.ini as needed
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