public short getContainerId() {
    return containerId;
  }
Gets the id of the {@link Container} where this blob belongs to. If this information was not available when
the blobId was formed, it will return {@link Container#UNKNOWN_CONTAINER_ID}.
@return The id of the {@link Container} where this blob belongs to.
ambry-commons/src/main/java/com/github/ambry/commons/BlobId.java