使用 journalctl -xe | grep logstash 命令查看日誌如下
Sep 13 16:37:23 am02 logstash[298460]: could not find java; set JAVA_HOME or ensure java is in PATH
Sep 13 16:37:23 am02 systemd[1]: logstash.service: main process exited, code=exited, status=1/FAILURE
Sep 13 16:37:23 am02 systemd[1]: Unit logstash.service entered failed state.
Sep 13 16:37:23 am02 systemd[1]: logstash.service failed.
Sep 13 16:37:23 am02 systemd[1]: logstash.service holdoff time over, scheduling restart.
Sep 13 16:37:23 am02 systemd[1]: start request repeated too quickly for logstash.service
Sep 13 16:37:23 am02 systemd[1]: Failed to start logstash.
我們看第一行內容，could not find java; set JAVA_HOME or ensure java is in PATH
使用echo $JAVA_HOME 查看是有值的. JAVA 的環境變量配置沒有問題.
我們進入到/usr/share/logstash/bin 查看logstash.lib.sh 文件.
加上如上這段
JAVA_HOME=/usr/java/jdk1.8.0_181
再次啓動logstash ，恢復正常.
systemctl start logstsh
