启动elasticsearch报错

could not find java; set JAVA_HOME or ensure java is in PATH

首先需要安装java

1、yum list installed |grep java  查看当前有没有装

有的话先卸载

yum -y remove java-1.8.0-openjdk*        *表时卸载所有openjdk相关文件输入

yum -y remove tzdata-java.noarch         卸载tzdata-java

安装java

yum  install  java-1.8.0-openjdk   java-1.8.0-openjdk-devel

启动

sudo -iu www-data /usr/local/elasticsearch/bin/elasticsearch -d #-d为后台启动

如果还有报错的话

Exception in thread "main" java.nio.file.AccessDeniedException: /usr/local/elasticsearch/config/jvm.

则要为当前用户添加权限

chown www-data /usr/local/elasticsearch -R

启动时，突然服务又停止的话，查看日志

max file descriptors [65535] for elasticsearch process is too low, increase to at least [65536]

解决方法：

1、vi /etc/sysctl.conf

设置fs.file-max=655350

保存之后sysctl -p使设置生效

2、vi /etc/security/limits.conf 新增

* soft nofile 655350

* hard nofile 655350

如报一下错误

max number of threads [3820] for user [www-data] is too low, increase to at least [4096]

修改如下:

1、修改配置文件/etc/security/limits.conf

* soft nproc 10240

* hard nproc 10240

* soft nofile 10240

* hard nofile 10240

2、然后重启即可

其中nofile对应open_files

nproc对应max_user_processes

通过 ulimit -a可以查看max_user_processes

搭建集群时，启动节点报错

[node-2] failed to send join request to master [{node-1}{EQwLRT_kSm6sI4KPwsMkKw}{ya57_AoaRaeQbCzJKShWMw}{172.16.100.199}{172.16.100.199:9300}], reason [RemoteTransportException[[node-1][172.16.100.199:9300][internal:discovery/zen/join]]; nested: IllegalArgumentException[can't add node {node-2}{EQwLRT_kSm6sI4KPwsMkKw}{DDv-R-CITnePbZNmPb_1Fw}{172.16.100.201}{172.16.100.201:9300}, found existing node {node-1}{EQwLRT_kSm6sI4KPwsMkKw}{ya57_AoaRaeQbCzJKShWMw}{172.16.100.199}{172.16.100.199:9300} with the same id but is a different node instance]; ]

解决方法如下，节点data文件下的文件清空。