ElasticSearch启动报错
修改 elasticsearch.yml 配置文件，允许外网访问。
VIM config/elasticsearch.yml
network.host: 0.0.0.0
启动失败，检查没有通过，报错
[2018-05-18T17:44:59,658][INFO ][o.e.b.BootstrapChecks ] [gFOuNlS] bound or publishing to a non-loopback address, enforcing bootstrap checks
ERROR: [2] bootstrap checks failed
[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 [4096] for Elasticsearch process is too low, increase to at least [65536]
编辑 /etc/security/limits.conf，追加以下内容；
* soft nofile 4096
* 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
重新启动，成功。
bin/elasticsearch
如果保存：the default discovery settings are unsuitable for production use; at least one of [discovery.seed_hosts, discovery.seed_providers, cluster.initial_master_nodes] must be configured
请打开：cluster.initial_master_nodes: ["master"] 配置
启动不能使用 root 账号，需要新建一个账号。
groupadd elastic
useradd elastic -g elastic -p 123456
然后解决下权限问题：chown -R elastic:elastic /opt/soft/es
-R 是循环设置
开启加密：
bin/elasticsearch-setup-passwords interactive