CODEWITHSUNDEEP
dockerdockerfile
AxD
AxD

Reputation: 3182

What is the purpose of advertising a VOLUME in the Dockerfile if it can be omitted?

I noticed by accident that it doesn't make a difference whether I advertise a VOLUME in the Dockerfile or not. (The Oracle database xe18.4 lacks the VOLUME statement) When I docker run -v ... the volume gets created without error.

What's the purpose of advertising a VOLUME in the Dockerfile if it can be omitted just as well?

Upvotes: 0

Views: 26

Answers (1)

larsks
larsks

Reputation: 312370

What's the purpose of advertising a VOLUME in the Dockerfile if it can be omitted just as well?

It means that when you run the container, any files created at that location are stored in a volume, rather than in the container root filesystem. This means that those files can be shared with other containers using e.g. --volumes-from (or an explicit reference to the volume).

It's also an explicit source of documentation -- if you want to persist storage beyond the lifecycle of your container, the VOLUME directive is telling you where you should mount your named volume or bind mount.

Upvotes: 1

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