编写启动脚本 elasticsearch.sh

• 懒人编写一个用于启动、停止和重启Elasticsearch服务的shell脚本
• 脚本中设置环境变量，并使用su - es - c命令在es用户下执行操作
• 通过赋予脚本执行权限，用户可以方便地对Elasticsearch进行控制

#!/bin/sh
 
export JAVA_HOME=/opt/software/java11/jdk-11.0.11
export PATH=$JAVA_HOME/bin:$PATH
export ES_HOME=/opt/software/elasticsearch/elasticsearch-7.6.1
export PATH=$ES_HOME/bin:$PATH

if [ $# -lt 1 ]
then
	echo "No Args Input..."
	exit ;
fi
 
 
case $1 in
    start)
        su - es -c "$ES_HOME/bin/elasticsearch -d -p pid"
        echo "elasticsearch is started"
        ;;
    stop)
        pid=`ps aux|grep elasticsearch | grep -v 'grep elasticsearch' | awk '{print $2}'`
        kill -9 $pid
        echo "elasticsearch is stopped"
        ;;
    restart)
        pid=`ps aux|grep elasticsearch | grep -v 'grep elasticsearch' | awk '{print $2}'`
        kill -9 $pid
        echo "elasticsearch is stopped"
        sleep 1
        su - es -c "$ES_HOME/bin/elasticsearch -d -p pid"
        echo "elasticsearch is started"
        ;;
    *)
        echo "start|stop|restart"
        ;;
esac
exit 0

赋予执行权限：

chmod +x elasticsearch.sh

参数说明：

su - es -c “命令”， 这个表示脚本内切换es用户一次并执行 -c 后面的命令，然后退出es普通用户到当前用户。

启动可能报错：elasticsearch 7.10启动报错 bootstrap checks failed

elasticsearch 7.14启动报错 bootstrap checks failed
现象一
ES使用root用户安装报错如下

Caused by: java.lang.RuntimeException: can not run elasticsearch as root

[root@localhost elasticsearch-7.14.2]# ./bin/elasticsearch
[2022-09-18T16:40:41,166][ERROR][o.e.b.ElasticsearchUncaughtExceptionHandler] [localhost.localdomain] uncaught exception in thread [main]
org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root
        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:163) ~[elasticsearch-7.14.2.jar:7.14.2]
        at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:150) ~[elasticsearch-7.14.2.jar:7.14.2]
        at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:75) ~[elasticsearch-7.14.2.jar:7.14.2]
        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:116) ~[elasticsearch-cli-7.14.2.jar:7.14.2]
        at org.elasticsearch.cli.Command.main(Command.java:79) ~[elasticsearch-cli-7.14.2.jar:7.14.2]
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:115) ~[elasticsearch-7.14.2.jar:7.14.2]
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:81) ~[elasticsearch-7.14.2.jar:7.14.2]
Caused by: java.lang.RuntimeException: can not run elasticsearch as root
        at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:103) ~[elasticsearch-7.14.2.jar:7.14.2]
        at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:170) ~[elasticsearch-7.14.2.jar:7.14.2]
        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:399) ~[elasticsearch-7.14.2.jar:7.14.2]
        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:159) ~[elasticsearch-7.14.2.jar:7.14.2]
        ... 6 more
uncaught exception in thread [main]
java.lang.RuntimeException: can not run elasticsearch as root
        at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:103)
        at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:170)
        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:399)
        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:159)
        at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:150)
        at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:75)
        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:116)
        at org.elasticsearch.cli.Command.main(Command.java:79)
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:115)
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:81)
For complete error details, refer to the log at /opt/ES/elasticsearch-7.14.2/logs/elasticsearch.log

解决方法

ES官方为了安全起见，禁止启用Root启动ES服务，因此我们需要进行普通用户的创建，才能正常启动ES服务。所以我们需要新建一个普通用户，并将ES安装目录授权给刚新建的用户。

[root@localhost ES]# useradd es

错误信息：

ERROR: [1] bootstrap checks failed
[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65535]
[2]: max number of threads [3795] for user [es] is too low, increase to at least [4096]
[3]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]

问题原因：

es高版本对资源要求较高，linux系统默认配置不能满足它的要求，所以需要单独配置

解决方法：

[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65535]

修改vi /etc/security/limits.conf 文件，加入配置

* hard nofile 65535  # *可以是es启动用户
* soft nofile 65535

可以指定用户

[2]: max number of threads [3795] for user [es] is too low, increase to at least [4096]

修改vi /etc/security/limits.conf 文件，加入配置

es - nproc 4096   # es是我的启动用户

注意 退出xshell，重新登录： 上面两个配置项改完后，ES启动用户(es 或root) 重新登录就会生效；

[3]：max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]

修改/etc/sysctl.config文件，加入下面配置

vi /etc/sysctl.conf

vm.max_map_count=262144

执行命令，立即生效

/sbin/sysctl -p
vm.max_map_count = 262144

启动成功