The database schema for metadata is inaccurate, and the namespace name cannot be version

[Iceber]

Description

The version key should actually be in the v1 buckets.

containerd/metadata/buckets.go

Lines 45 to 55 in b9bffd1

	// Below is the current database schema. This should be updated each time
	// the structure is changed in addition to adding a migration and incrementing
	// the database version. Note that `╘══*...*` refers to maps with arbitrary
	// keys.
	// ├──version : <varint> - Latest version, see migrations
	// └──v1 - Schema version bucket
	// ╘══*namespace*
	// ├──labels
	// │  ╘══*key* : <string> - Label value
	// ├──image
	// │  ╘══*image name*

code:

containerd/metadata/db.go

Lines 194 to 204 in b9bffd1

	bkt, err := tx.CreateBucketIfNotExists(bucketKeyVersion)
	if err != nil {
	return err
	}
	versionEncoded, err := encodeInt(dbVersion)
	if err != nil {
	return err
	}
	return bkt.Put(bucketKeyDBVersion, versionEncoded)

use bbolt cmd

root@iceber-master:~# ./bbolt keys  /var/lib/containerd/io.containerd.metadata.v1.bolt/meta.db v1
default
k8s.io
moby
stress
version

And the namespace name cannot be version.

root@iceber-master:~# ctr namespaces create version
ctr: incompatible value: unknown

Describe the results you received and expected

Could we change the database schema to

// Below is the current database schema. This should be updated each time
// the structure is changed in addition to adding a migration and incrementing
// the database version. Note that `╘══*...*` refers to maps with arbitrary
// keys.
//  └──v1                                        - Schema version bucket
//     ├──version : <varint>                     - Latest version, see migrations
//     ╘══*namespace*
//        ├──labels
//        │  ╘══*key* : <string>                 - Label value
//        ├──image

and verify that it is equal to version when creating the namespace?

What version of containerd are you using?

containerd github.com/containerd/containerd 1.5.2-0ubuntu1~20.04.2

Any other relevant information

No response

Show configuration if it is related to CRI plugin.

No response

[AkihiroSuda]

It might be difficult to change the schema without breaking existing data. I'd suggest just mark this wontfix and add a document to explain that a namespace cannot be named "version".

[Iceber]

Yes, it is difficult to change the schema used in the metadata, but the metadata schema comment is inaccurate and does the schema comment need to be changed to be consistent with the current implementation？

Or is it just necessary to explain in the namespace doc that namespce cannot be named ”version“.

[AkihiroSuda]

Yes, the comment has to be updated

[fuweid]

fixed by #6955