[manage-images] Clarify character limitations on image names

Signed-off-by: Kyle Squizzato <kyle.squizzato@docker.com>
This commit is contained in:
Kyle Squizzato 2018-08-01 16:17:26 -04:00
parent d95f61dbcd
commit a9840a3e33
1 changed files with 13 additions and 3 deletions

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@ -34,9 +34,19 @@ When creating a repository in DTR, the full name of the repository becomes
`<dtr-domain-name>/<user-or-org>/<repository-name>`. In this example, the full
name of our repository will be `dtr.example.org/dave.lauper/golang`.
DTR only allows image names with 255 characters. This includes the domain,
organization, and repository name. When you create a repository, make sure
its full name has less than 255 characters.
When creating an image name for use with DTR ensure that the organization and
repository name has less than 56 characters and that the entire image name
which includes domain, organization and repository name does not exceed 255
characters.
*The 56 character `<user-or-org/repository-name>` limit in DTR is due to an
underlying limitation in how the image name information is stored within
DTR metadata in RethinkDB. RethinkDB currently has a Primary Key length limit
of 127 characters.
When DTR stores the above data it appends a sha256sum comprised of 72 characters
to the end of the value to ensure uniqueness within the database. If the `<user-or-org/repository-name>` exceeds 56 characters it will then exceed the
127 character limit in RethinkDB (72+56=128).*
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