[HADOOP-8694] Create true symbolic links on Windows

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1-win
• Fix Version/s: 1-win
• Hadoop Flags: Reviewed
• Assignee: Chuan Liu
• Reporter: Chuan Liu
• Created: 13/Aug/12 23:31
• Updated: 01/Oct/12 20:28
• Resolved: 01/Oct/12 20:28

Description

In branch-1-win, we currently copy files for symbolic links in Hadoop on Windows. We have talked to davidlao who made the original fix, and did some investigation on Windows. Windows began to support symbolic links (symlinks) since Vista/Server 2008. The original reason to copy files instead of creating actual symlinks is that only Administrators has the privilege to create symlinks on Windows by default. After talking to NTFS folks, we knew the reason for that is mostly due to security, and this default behavior may not be changed in near future. Though this behavior can be changed via the Local Security Policy management console, i.e. secpol.msc, under Security Settings\Local Policies\User Rights Assignment\Create symbolic links.

In Hadoop, symlinks is mostly used to for DistributedCache and attempted logs. We felt the usages are important enough for us to provide true symlinks support, and users need to have the symlink creation privilege enabled on Windows to use Hadoop.

This JIRA is created to tracking symlink support on Windows.

Issue Links

• blocks: HBASE-6817 [WINDOWS] Get HBase tests working under Windows
• is part of: HADOOP-8645 Stabilize branch-1-win