CentOS 7 启动ElasticSearch时报错bootstrap checks failed

错误：

[2021-01-27T11:50:22,939][INFO ][o.e.b.BootstrapChecks    ] [cnetos7.hanhua.com] bound or publishing to a non-loopback address, enforcing bootstrap checks
ERROR: [3] bootstrap checks failed
[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65535]
[2]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
[3]: system call filters failed to install; check the logs and fix your configuration or disable system call filters at your own risk
[4]: max number of threads [1024] for user [lish] likely too low, increase to at least [2048]
ERROR: Elasticsearch did not exit normally - check the logs at /usr/local/elasticsearch7/logs/elasticsearch.log

第一个问题：
max file descriptors [1024] for elasticsearch process is too low, increase to at least [4029]

解决方案：
limits.conf，追加以下内容

vim /etc/security/limits.conf
* soft nofile 65536
* hard nofile 65536

注：如果编辑重启启动之后还不能消除这个错误，则重登陆用户。

第二个问题：
max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]

解决方案：
sysctl.conf，追加以下内容：

[root@cnetos7 elasticsearch7]# vim /etc/sysctl.conf
vm.max_map_count=262144

保存后，执行：

[root@cnetos7 elasticsearch7]# sysctl -p

重新启动，成功。

第三个问题：
system call filters failed to install; check the logs and fix your configuration or disable system call filters at your own risk

出现错误的原因：是因为centos6.x操作系统不支持SecComp，而elasticsearch 5.5.2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。

解决方案：
在elasticsearch.yml中添加配置项：

[root@cnetos7 config]# vim elasticsearch.yml
bootstrap.memory_lock:  false
bootstrap.system_call_filter: false

第四个问题：
max number of threads [1024] for user [wh] likely too low, increase to at least [2048]

解决方案：
修改如下内容：

[root@cnetos7 config]# vim /etc/security/limits.d/90-nproc.conf 
soft nproc 1024
#修改为
soft nproc 2048

注：以上问题如果编辑重启启动之后还不能消除这个错误，则重登陆用户。