安装elasticsearch 5.x, 6.x 常见问题（坑）的解决

本人在elasticsearch 5.x, 6.x 安装过程中遇到了一些问题：

警告提示

[2016-11-06T16:27:21,712][WARN ][o.e.b.JNANatives ] unable to install syscall filter:

java.lang.UnsupportedOperationException: seccomp unavailable: requires kernel 3.5+ with CONFIG_SECCOMP and CONFIG_SECCOMP_FILTER compiled in

at org.elasticsearch.bootstrap.Seccomp.linuxImpl(Seccomp.java:349) ~[elasticsearch-5.0.0.jar:5.0.0]

at org.elasticsearch.bootstrap.Seccomp.init(Seccomp.java:630) ~[elasticsearch-5.0.0.jar:5.0.0]

报了一大串错误，其实只是一个警告。使用心得linux版本，就不会出现此类问题了。

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]

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，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

* hard nofile

* soft nproc

* hard nproc

对于第二条错误同意需要切换到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 4096

第三条错误需要切换到root用户修改配置sysctl.conf

vi /etc/sysctl.conf

添加下面配置：

vm.max_map_count=

并执行命令：

sysctl -p

然后，重新启动elasticsearch，即可启动成功。

启动问题

**1、Java HotSpot(TM) 64-Bit Server VM warning: INFO: os::commit_memory(0x0000000085330000, 2060255232, 0) failed; error='Cannot allocate memory' (errno=12)**

由于elasticsearch5.0默认分配jvm空间大小为2g，修改jvm空间分配

# vim config/jvm.options

-Xms2g

-Xmx2g

修改为

-Xms512m

-Xmx512m

2、max number of threads [1024] for user [elasticsearch] is too low, increase to at least [2048]修改 /etc/security/limits.d/90-nproc.conf

*          soft    nproc

*          soft    nproc

3、max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
修改/etc/sysctl.conf配置文件，

cat /etc/sysctl.conf | grep max_map_count

如果不存在则添加

echo "vm.max_map_count=655360" >>/etc/sysctl.conf

4、max file descriptors [65535] for elasticsearch process likely too low, increase to at least [65536]
需要执行下面的命令

ulimit -n 65536

5. 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

　　原因：
　　这是在因为Centos6不支持SecComp，而ES5.2.0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：
　　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

`成功的画面：`