[HDDS-1089] Disable OzoneFSStorageStatistics for hadoop versions older than 2.8

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.4.0
• Component/s: Ozone Filesystem
• Labels: pull-request-available
• Target Version/s: 0.4.0
• Assignee: Marton Elek
• Reporter: Marton Elek
• Created: 12/Feb/19 12:35
• Updated: 07/Mar/19 09:00
• Resolved: 24/Feb/19 21:57

Description

HDDS-1033 introduced OzoneFSStorageStatistics for OzoneFileSystem. It uses the StorageStatistics which is introduced in HADOOP-13065 (available from the hadoop2.8/3.0).

Using older hadoop (for example hadoop-2.7 which is included in the spark distributions) is not possible any more even with using the isolated class loader (introduced in HDDS-922).

Fortunately it can be fixed:

1. We can support null in storageStatistics field with checking everywhere before call it.
2. We can create a new constructor of OzoneClientAdapterImpl without using OzoneFSStorageStatistics): If OzoneFSStorageStatistics is not in the method/constructor signature we don't need to load it.
3. We can check the availability of HADOOP-13065 and if the classes are not in the classpath we can skip the initialization of the OzoneFSStorageStatistics

Issue Links

• links to: GitHub Pull Request #501