一、Exception in thread "main" SettingsException[Failed to load settings from [elasticsearch.yml]]; nested: ElasticsearchParseException[malformed, expected settings to start with 'object', instead was [VALUE_STRING]];

原因：elasticsearch.yml文件错误

解决：参数与参数值等号间需要空格

node.name ="node"  ##错误
node.name = "node" ##正确

二、org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root

详细错误：

OpenJDK 64-Bit Server VM warning: If the number of processors is expected to increase from one, then you should configure the number of parallel GC threads a
[2018-06-20T02:19:58,978][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:140) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:127) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124) ~[elasticsearch-cli-6.3.0.jar:6.3.0]
	at org.elasticsearch.cli.Command.main(Command.java:90) ~[elasticsearch-cli-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:93) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:86) ~[elasticsearch-6.3.0.jar:6.3.0]
Caused by: java.lang.RuntimeException: can not run elasticsearch as root
	at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:104) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:171) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:326) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:136) ~[elasticsearch-6.3.0.jar:6.3.0]
	... 6 more

原因：处于对root用户的安全保护，需要使用其他用户组进行授权启动

解决：

step1:用户组进行授权启动

groupadd elsearch           
useradd elsearch -g elsearch -p elasticsearch
chown -R elsearch:elsearch  elasticsearch-6.3.0

备注： 添加用户组 elsearch  
      添加用户 elsearch 密码为 elasticsearch 到用户组 elsearch
      将elsearch安装目录授权给 用户组：用户  即 elsearch：elsearch

step2: 重新启动

su elsearch
/elasticsearch-6.3.0/bin/elasticsearch

备注：切换 elsearch 用户
      重新启动

三、OpenJDK 64-Bit Server VM warning: INFO: os::commit_memory(0x0000000085330000, 2060255232, 0) failed; error='Cannot a ...'(errno=12);

原因：jvm要分配最大内存超出系统内存

解决：

step1：适当调整指定jvm内存

vi /home/elasticsearch-6.3.0/config/jvm.options 

备注：编辑elasticsearch jvm配置文件 修改如下 esc+：wq保存退出

## JVM configuration

################################################################
## IMPORTANT: JVM heap size
################################################################
##
## You should always set the min and max JVM heap
## size to the same value. For example, to set
## the heap to 4 GB, set:
##
## -Xms4g
## -Xmx4g
##
## See https://www.elastic.co/guide/en/elasticsearch/reference/current/heap-size.html
## for more information
##
################################################################

# Xms represents the initial size of total heap space
# Xmx represents the maximum size of total heap space

-Xms512m
-Xmx512m

备注：由于虚拟机内存制定1g，所以适当降低jvm内存指定

step2:重启

su elsearch
/elasticsearch-6.3.0/bin/elasticsearch

四、ERROR: [3] bootstrap checks failed

详细错误：

[2018-06-20T02:35:47,152][INFO ][o.e.b.BootstrapChecks    ] [SUcoFrg] 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 [65536]
[2]: max number of threads [3802] for user [elsearch] is too low, increase to at least [4096]
[3]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
[2018-06-20T02:35:47,170][INFO ][o.e.n.Node               ] [SUcoFrg] stopping ...
[2018-06-20T02:35:47,316][INFO ][o.e.n.Node               ] [SUcoFrg] stopped
[2018-06-20T02:35:47,316][INFO ][o.e.n.Node               ] [SUcoFrg] closing ...
[2018-06-20T02:35:47,336][INFO ][o.e.n.Node               ] [SUcoFrg] closed

原因：虚拟机限制用户的执行内存

解决：

[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]

[2]: max number of threads [3802] for user [elsearch] is too low, increase to at least [4096]

step1:修改安全限制配置文件

su root 
vi /etc/security/limits.conf

备注：使用最高权限 修改安全配置 在文件末尾加入

# End of file
elsearch       hard        nofile        65536 
elsearch       soft        nofile        65536
*               soft       nproc         4096
*               hard       nproc         4096 

备注： elsearch为用户名 可以是使用*进行通配  
nofile 最大打开文件数目
nproc 最大打开线程数目

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

step2:修改系统配置文件

vi /etc/sysctl.conf 

备注：行末加上vm.max_map_count = 655360 ，esc +：wq保存退出

# sysctl settings are defined through files in
# /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
#
# Vendors settings live in /usr/lib/sysctl.d/.
# To override a whole file, create a new file with the same in
# /etc/sysctl.d/ and put new settings there. To override
# only specific settings, add a file with a lexically later
# name in /etc/sysctl.d/ and put new settings there.
#
# For more information, see sysctl.conf(5) and sysctl.d(5).
vm.max_map_count = 655360

备注：vm.max_map_count = 655360 值大于错误提示值

step3:重启

su elsearch
/elasticsearch-6.3.0/bin/elasticsearch

五、org.elasticsearch.bootstrap.StartupException: java.lang.IllegalStateException: failed to obtain node locks, tried [[/home/elasticsearch-6.3.0/data/elasticsearch]] with lock id [0]; maybe these locations are not writable or multiple nodes were started without increasing [node.max_local_storage_nodes] (was [1])?

[2018-06-20T04:23:25,003][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [] uncaught exception in thread [main]
org.elasticsearch.bootstrap.StartupException: java.lang.IllegalStateException: failed to obtain node locks, tried [[/home/elasticsearch-6.3.0/data/elasticsearch]] with lock id [0]; maybe these locations are not writable or multiple nodes were started without increasing [node.max_local_storage_nodes] (was [1])?
	at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:140) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:127) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124) ~[elasticsearch-cli-6.3.0.jar:6.3.0]
	at org.elasticsearch.cli.Command.main(Command.java:90) ~[elasticsearch-cli-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:93) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:86) ~[elasticsearch-6.3.0.jar:6.3.0]
Caused by: java.lang.IllegalStateException: failed to obtain node locks, tried [[/home/elasticsearch-6.3.0/data/elasticsearch]] with lock id [0]; maybe these locations are not writable or multiple nodes were started without increasing [node.max_local_storage_nodes] (was [1])?
	at org.elasticsearch.env.NodeEnvironment.<init>(NodeEnvironment.java:243) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.node.Node.<init>(Node.java:270) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.node.Node.<init>(Node.java:252) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Bootstrap$5.<init>(Bootstrap.java:213) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:213) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:326) ~[elasticsearch-6.3.0.jar:6.3.0]
	at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:136) ~[elasticsearch-6.3.0.jar:6.3.0]
	... 6 more

原因：线程占用

解决：重新启动

step1:杀死elasticsearch线程

ps -ef | grep elastic

kill -9 2002

step2: 重启

su elsearch
/elasticsearch-6.3.0/bin/elasticsearch

六、验证

1、后台启动

 /home/elasticsearch-6.3.0/bin/elasticsearch -d

2、curl验证

curl http://zk01:9200

3、网站验证