HDDS-6561. Modify default bucket layout to LEGACY.

[JyotinderSingh]

What changes were proposed in this pull request?

This task to modify the existing default bucket layout at the OM server and Ozone shell command to LEGACY.

OMConfigKeys.java#L283

ozone.default.bucket.layout = LEGACY

CreateBucketHandler.java#L64

  @Option(names = { "--layout", "-l" },
      description = "Allowed Bucket Layouts: ${COMPLETION-CANDIDATES}",
      defaultValue = "OBJECT_STORE")

Changing to LEGACY will make the cluster upgrades easier. An older version client can talk to the new OM server using LEGACY buckets.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-6561

How was this patch tested?

Integration tests.

[rakeshadr]

Please remove the test config that introduced to satisfy default OBS behavior at the OM server side.

OzoneConfigKeys.java

  public static final String OZONE_CLIENT_TEST_OFS_DEFAULT_BUCKET_LAYOUT =
      "ozone.client.test.ofs.default.bucket.layout";

       // Fetches the bucket layout to be used by OFS.
      this.defaultOFSBucketLayout = BucketLayout.fromString(
          conf.get(OzoneConfigKeys.OZONE_CLIENT_TEST_OFS_DEFAULT_BUCKET_LAYOUT,
              OzoneConfigKeys.OZONE_CLIENT_TEST_OFS_BUCKET_LAYOUT_DEFAULT));

[rakeshadr]

@JyotinderSingh Adding one more point to the above, no need to persist LEGACY layout in the OM DB. Only persist OBS or FSO layouts. Please feel free to create a separate task if it requires more changes.

public class OmBucketInfoCodec implements Codec<OmBucketInfo> {

  @Override
  public byte[] toPersistedFormat(OmBucketInfo object) throws IOException {
    Preconditions
        .checkNotNull(object, "Null object can't be converted to byte array.");
    return object.getProtobuf().toByteArray();
  }

[JyotinderSingh]

Please remove the test config that introduced to satisfy default OBS behavior at the OM server side.

OzoneConfigKeys.java

  public static final String OZONE_CLIENT_TEST_OFS_DEFAULT_BUCKET_LAYOUT =
      "ozone.client.test.ofs.default.bucket.layout";

       // Fetches the bucket layout to be used by OFS.
      this.defaultOFSBucketLayout = BucketLayout.fromString(
          conf.get(OzoneConfigKeys.OZONE_CLIENT_TEST_OFS_DEFAULT_BUCKET_LAYOUT,
              OzoneConfigKeys.OZONE_CLIENT_TEST_OFS_BUCKET_LAYOUT_DEFAULT));

Done

[rakeshadr]

+1 LGTM, Thanks @JyotinderSingh for the contribution.