启动elasticsearch报错的几种原因及解决方法

ERROR: [1] bootstrap checks failed
[1]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]

解决：

在宿主机执行：

sysctl -w vm.max_map_count=262144

原因：

vm.max_map_count参数，是允许一个进程在VMAs拥有最大数量（VMA：虚拟内存地址， 一个连续的虚拟地址空间），当进程占用内存超过时， 直接OOM。

elasticsearch占用内存较高。官方要求max_map_count需要配置到最小262144。

问题

Java HotSpot(TM) 64-Bit Server VM warning: INFO: os::commit_memory(0x00000000c5330000, 986513408, 0) failed; error='Cannot allocate memory' (errno=12)
#
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 986513408 bytes for committing reserved memory.
# An error report file with more information is saved as:
# /usr/local/software/temp/elasticsearch-6.2.2/hs_err_pid1912.log

解决：

内存不够，购买阿里云的机器可以动态增加内存，或者启动时候现在内存为256M

问题:

[root@iZwz95j86y235aroi85ht0Z bin]# ./elasticsearch
[2018-02-22T20:14:04,870][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [] uncaught exception in thread [main]
org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root
at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:125) ~[elasticsearch-6.2.2.jar:6.2.2]
at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:112) ~[elasticsearch-6.2.2.jar:6.2.2]
at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86) ~[elasticsearch-6.2.2.jar:6.2.2]
at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124) ~[elasticsearch-cli-6.2.2.jar:6.2.2]

解决：

用非root用户
添加用户：useradd -m 用户名 然后设置密码 passwd 用户名

问题:

./elasticsearch
Exception in thread "main" java.nio.file.AccessDeniedException: /usr/local/software/temp/elasticsearch-6.2.2/config/jvm.options

解决：

权限不够 chmod 777 -R 当前es目录

max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536] 
解决方案

[root@centos7 sonarqube-7.2.1]# vi /etc/security/limits.conf
pangkunkun1 hard nofile 65536
pangkunkun1 soft nofile 65536

这里的pangkunkun1为上面创建的用来启动sonar的用户，修改好之后要切换到pangkunkun1这个用户之后才能生效。 
使用ulimit -Hn指令查看配置是否生效：

[pangkunkun1@centos7 sonarqube-7.2.1]$ ulimit -Hn
65536