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The "SocketPathSecurity" page has been changed by SteveLoughran:
https://wiki.apache.org/hadoop/SocketPathSecurity

Comment:
New page to go with HADOOP-12344: validateSocketPathSecurity0 message could be 
better

New page:
 = Socket Path Security =

On Linux and potentially other Unix platforms, Apache Hadoop can support higher 
performance access to HDFS data via [[Unix domain 
sockets|https://en.wikipedia.org/wiki/Unix_domain_socket].

These objects live in the unix filesystem, and, when opened by the both the 
datanode and a local process (such as HBase), allows the local process to

 1. Bypass the TCP stack for less communications overhead.
 1. Share file descriptors so that read operations may actually be done in the 
local process.

To ensure data security and integrity, Hadoop will not use these sockets if the 
filesystem permissions of the domain socket are inadequate.

If you were referred to this page by an exception in the Hadoop logs, then 
Hadoop considers the configuration of the domain socket insecure.

This means
 1. Nobody malicious can overwrite the entry with their own socket. The entire 
path to the socket must not contain any world-writeable directory.
 1. No entry in the path is group writeable, except in the special case that 
the owner is root (and of course the group must be one containing
only trusted accounts)
 1. The owner of the file is neither root nor the "effective user" trying to 
work with the socket.

All these requirements are checked, and attempts to use Domain Sockets will 
fail if they are unmet.

They can be addressed through tightening the permissions and changing user and 
group details. The exceptions should provide enough information to help you get 
started here.

Finally, these are not problems in the Hadoop code, they are related to the 
configuration of your servers. Filing bugs about these exceptions is likely to 
result in them being closed as [[Invalid|InvalidJiraIssues]

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