data stored in the mysql database will be lost if the container is stopped? about docker-redmine HOT 7 CLOSED

@peefour data is not lost if the container is stopped and started. but if you delete it, it's gone for sure, unless you commit the changes.

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@peefour this is the main reason why volumes can be mounted in docker.

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ah ok ;)
thank you!

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on another note, you say that you will remove mysql from the docker instance ( indeed the philosophy behind docker is that every service has its own container), but for me I like to have all related services in one container. so I would appreciate it if mysql (and apache etc) will stay in the container ;)

thanks very much!

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@peefour the idea is each container should provide a single service. in this case it would be the redmine application. Any additional services that the application requires, like a database server, should be availed from other containers (service discovery) or configured manually.

How this helps:

1. reduced size of the image. Removing mysql-server alone trims the image size by ~100MB.
2. reduced image complexity in the sense that we only deal with the working of redmine and not the mysql server. For example, in another image (sameersbn/gitlab), i have an issue report saying that the mysql server is not starting. Now debugging that issue is a pain because there are too many variables in the container. If it was just a container that provided a mysql database server it would have been simple to figure out the issue.
3. You can share services between containers. For example, redmine requires a database server and lets say we select a postgresql server for this and use the sameersbn/postgresql container. Now say another application, eg. gitlab, also requires a database server and since we already have a postgresql container running we can simply use it.
   The alternate way would be to run a postgresql server in the redmine container and another postgresql server in the gitlab container. As you can already tell this would not be optimal.

As an aside, It is advisable to use postgresql server over mysql for the simple reason being postgresql performs much better with multiple cores/cpus and in today's world who does not have a multicore cpu. PostgreSQL beats the stuffing out of MySQL.

P.S. This is a blog post from 2006, so things could have changed over the years. Do your own research.

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hi,

thanks for the extensive info sameer ;)
I understand the rationale behind it, and it makes a lot of sense, especially in corporate environments.
But having everything in one container has also benefits, because having everything in several containers means more configurations, network links, and complexity. For non-professional use of redmine (in my case) that's a bit overkill ;)

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@peefour well starting an additional container cannot be an overkill :)

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