當把ElasticSearch部署好之後，然後進入到elasticsearch/bin目錄下執行

./elasticsearch

log4j:ERROR setFile(null,true) call failed.
java.io.FileNotFoundException: /usr/local/elasticsearch/logs/elasticsearch.log
        at java.io.FileOutputStream.open(Native Method)

        at java.io.FileOutputStream.<init>(FileOutputStream.java:221)

        at java.io.FileOutputStream.<init>(FileOutputStream.java:142)

        at org.apache.log4j.FileAppender.setFile(FileAppender.java:294)

        at org.apache.log4j.FileAppender.activateOptions(FileAppender.java:165)

        at org.apache.log4j.DailyRollingFileAppender.activateOptions(DailyRollingFileAppender.java:223)

        at org.apache.log4j.config.PropertySetter.activate(PropertySetter.java:307)

        at org.apache.log4j.config.PropertySetter.setProperties(PropertySetter.java:172)

        at org.apache.log4j.config.PropertySetter.setProperties(PropertySetter.java:104)

        at org.apache.log4j.PropertyConfigurator.parseAppender(PropertyConfigurator.java:842)

        at org.apache.log4j.PropertyConfigurator.parseCategory(PropertyConfigurator.java:768)

        at org.apache.log4j.PropertyConfigurator.configureRootCategory(PropertyConfigurator.java:648)

        at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:514)

        at org.apache.log4j.PropertyConfigurator.configure(PropertyConfigurator.java:440)

        at org.elasticsearch.common.logging.log4j.LogConfigurator.configure(LogConfigurator.java:128)

        at org.elasticsearch.bootstrap.Bootstrap.setupLogging(Bootstrap.java:204)

        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:258)

        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:35)
 

一開始以為是目前許可權不夠，在前面加上sudo 之後執行，還是報錯：

Exception in thread "main" java.lang.RuntimeException: don't run elasticsearch as root.
        at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:93)

        at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:144)

        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:285)

        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:35)

Refer to the log for complete error details.
 

sudo chown -R hadoop:hadoop elasticsearch-5.5.0
sudo chgrp -R hadoop:hadoop elasticsearch-5.5.0

原因說明：由於ElasticSearch可以接收使用者的指令碼並執行，處於安全性考慮，建議建立一個單獨的使用者來執行ElasticSearch。當然，可以通過配置來實現root使用者啟動。

修改bin目錄elasticsearch.in.sh檔案中追加（不過不建議）：

JAVA_OPTS="$JAVA_OPTS -Des.insecure.allow.root=true"