I have the same problem but under Windows
Log4j file is not find, but it exist in E:/MCO/TDB/bin/logstash-5.0.0/config/log4j2.properties
The log show an error on "java.net.UnknownHostException: E".
It seems that E is the drive of the log4j path.
C:\Users\hugues>E:\MCO\TDB\bin\logstash-5.0.0\bin\logstash -f "E:\MCO\TDB\Datasource\StoZ_Batch\test.conf"
ERROR StatusLogger Unable to access file://E:/MCO/TDB/bin/logstash-5.0.0/config/log4j2.properties
java.net.UnknownHostException: E
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.ftp.impl.FtpClient.doConnect(Unknown Source)
at sun.net.ftp.impl.FtpClient.tryConnect(Unknown Source)
at sun.net.ftp.impl.FtpClient.connect(Unknown Source)
at sun.net.ftp.impl.FtpClient.connect(Unknown Source)
at sun.net.www.protocol.ftp.FtpURLConnection.connect(Unknown Source)
at sun.net.www.protocol.ftp.FtpURLConnection.getInputStream(Unknown Source)
at java.net.URL.openStream(Unknown Source)
at org.apache.logging.log4j.core.config.ConfigurationFactory.getInputFromUri(ConfigurationFactory.java:299)
at org.apache.logging.log4j.core.config.ConfigurationFactory.getConfiguration(ConfigurationFactory.java:234)
at org.apache.logging.log4j.core.config.ConfigurationFactory$Factory.getConfiguration(ConfigurationFactory.java:433)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:237)
at org.apache.logging.log4j.core.config.Configurator.initialize(Configurator.java:157)
at org.apache.logging.log4j.core.config.Configurator.initialize(Configurator.java:130)