private void findHostname ( ) { String startupInfo = Environment . runCommand ( "grep --max-count=1 STARTUP_MSG:\\s*host " + file . getName ( ) ) . toString ( ) ; Pattern pattern = Pattern . compile ( "\\s+(\\w+/.+)\\s+" ) ; Matcher matcher = pattern . matcher ( startupInfo ) ; if ( matcher . find ( 0 ) ) { hostname = matcher . group ( 1 ) . split ( "/" ) [ 0 ] ; ips = new String [ 1 ] ; ips [ 0 ] = matcher . group ( 1 ) . split ( "/" ) [ 1 ] ; } }
Attempt to determine the hostname of the node that created the log file . This information can be found in the STARTUP_MSG lines of the Hadoop log which are emitted when the node starts .