elasticsearch学习第一天

**Elasticsearch: 权威指南https://www.elastic.co/guide/cn/elasticsearch/guide/current/running-elasticsearch.html
1、下载、安装（根据官网指示，安装java
2、启动es
3、外网访问的话，需要修改es配置，config/elasticsearch.yml ，network.host: 0.0.0.0
4、后台运行 ./bin/elasticsearch -d
5、浏览器：http://XXXXX:8777/?pretty


这里写代码片
{
name: “gI_eExa”,
cluster_name: “elasticsearch”,
cluster_uuid: “lStVYu82RxOwKptLYODkdw”,
version: - {
number: “5.6.3”,
build_hash: “1a2f265”,
build_date: “2017-10-06T20:33:39.012Z”,
build_snapshot: false,
lucene_version: “6.6.1”
},
tagline: “You Know, for Search”
}

启动遇到的问题：
1、启动异常：ERROR: bootstrap checks failed
system call filters failed to install; check the logs and fix your configuration or disable system call filters at your own risk
问题原因：因为Centos6不支持SecComp，而ES5.2.1默认bootstrap.system_call_filter为true进行检测，所以导致检测失败，失败后直接导致ES不能启动。详见 ：https://github.com/elastic/elasticsearch/issues/22899

解决方法：在elasticsearch.yml中配置bootstrap.system_call_filter为false，注意要在Memory下面:
bootstrap.memory_lock: false
bootstrap.system_call_filter: false
问题二：ERROR: bootstrap checks failed

max file descriptors [4096] for elasticsearch process likely too low, increase to at least [65536]
max number of threads [1024] for user [lishang] likely too low, increase to at least [2048]

解决：切换到root用户，编辑limits.conf 添加类似如下内容

vi /etc/security/limits.conf

添加如下内容:

• soft nofile 65536

• hard nofile 131072

• soft nproc 2048

• hard nproc 4096

问题三：max number of threads [1024] for user [lish] likely too low, increase to at least [2048]

解决：切换到root用户，进入limits.d目录下修改配置文件。

vi /etc/security/limits.d/90-nproc.conf

修改如下内容：

• soft nproc 1024

修改为

• soft nproc 2048

问题四：max virtual memory areas vm.max_map_count [65530] likely too low, increase to at least [262144]

解决：切换到root用户修改配置sysctl.conf

vi /etc/sysctl.conf

添加下面配置：

vm.max_map_count=655360

并执行命令：

sysctl -p

然后，重新启动elasticsearch，即可启动成功