安装elasticsearch 5.x, 6.x 常见问题（坑）的解决
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 65536
* hard nofile 131072
* soft nproc 2048
* hard nproc 4096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=655360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 1024
* soft nproc 40963、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.conf4、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 655365. 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：
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