在centos7 安装Elasticsearch 步骤：
1. 下载安装包
wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-7.14.1-linux-x86_64.tar.gz
2. 解压
tar -zxvf xxx
3. 创建非root 用户
useradd qizhi
passwd xxx
4. 赋予权限
chown -R qizhi:qizhi xxx
5. 切换用户启动
su qizhi
./bin/elasticsearch -d
6. 测试
curl http://localhost:9200
7. 修改配置文件
#节点名称
node.name: localhost.localdomain
##监听IP
network.host: 192.168.157.132
##初始化设置
cluster.initial_master_nodes: ['localhost.localdomain']
8. 启动时遇到的问题
[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
[2]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
[1]: max file descriptors [65535] for elasticsearch process is too low, increase to at least [65536]
解决方案：
切换到root用户
编辑 /etc/security/limits.conf，追加以下内容；
* soft nofile 65536
* hard nofile 65536
此文件修改后需要重新登录用户，才会生效
[2]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
编辑 /etc/sysctl.conf，追加以下内容：
vm.max_map_count=655360
保存后，执行：
sysctl -p
重启
9. 关闭防火墙，外部访问
