Elasticsearch常见错误及解决方法：
1、启动时候报错：Caused by: : Cannot assign requested address
解决方法：打开配置文件 将 : 192.168.0.1 修改为本机IP 0.0.0.0
[2020-04-03T19:41:11,382][INFO ][ ] [txvm2019] starting ...
[2020-04-03T19:41:11,649][WARN ][] [txvm2019] uncaught exception in thread [main]
: BindTransportException[Failed to bind to [9300-9400]]; nested: BindException[Cannot assign requested address];
at (:163) ~[elasticsearch-7.2.:7.2.0]
at (:150) ~[elasticsearch-7.2.:7.2.0]
at (:86) ~[elasticsearch-7.2.:7.2.0]
at (:124) ~[elasticsearch-cli-7.2.:7.2.0]
at (:90) ~[elasticsearch-cli-7.2.:7.2.0]
at (:115) ~[elasticsearch-7.2.:7.2.0]
at (:92) ~[elasticsearch-7.2.:7.2.0]
Caused by: : Failed to bind to [9300-9400]
at (:389) ~[elasticsearch-7.2.:7.2.0]
at (:355) ~[elasticsearch-7.2.:7.2.0]
at .netty4.(:136) ~[?:?]
at .netty4.(:81) ~[?:?]
at .netty4.(:43) ~[?:?]
at (:59) ~[elasticsearch-7.2.:7.2.0]
at (:230) ~[elasticsearch-7.2.:7.2.0]
at (:59) ~[elasticsearch-7.2.:7.2.0]
at (:662) ~[elasticsearch-7.2.:7.2.0]
at (:273) ~[elasticsearch-7.2.:7.2.0]
at (:358) ~[elasticsearch-7.2.:7.2.0]
at (:159) ~[elasticsearch-7.2.:7.2.0]
... 6 more
Caused by: : Cannot assign requested address
at .bind0(Native Method) ~[?:?]
at (:433) ~[?:?]
at (:425) ~[?:?]
at (:223) ~[?:?]
at (:132) ~[?:?]
at $(:563) ~[?:?]
at $(:1332) ~[?:?]
at (:503) ~[?:?]
at (:488) ~[?:?]
at (:984) ~[?:?]
at (:259) ~[?:?]
at $(:366) ~[?:?]
at (:163) ~[?:?]
at (:405) ~[?:?]
at (:500) ~[?:?]
at $(:906) ~[?:?]
at $(:74) ~[?:?]
at (:745) [?:1.8.0_121]
2、错误：max number of threads [2048] for user [elasticsearch] is too low, increase to at least [4096]
解决方法：编辑 /etc/security/，追加以下内容；
soft nofile 65536
hard nofile 65536
[2020-04-03T19:46:34,046][INFO ][] [txvm2019] [controller/27023] [@110] controller (64 bit): Version 7.2.0 (Build 65aefcbfce449b) Copyright (c) 2019 Elasticsearch BV
[2020-04-03T19:46:34,526][DEBUG][ ] [txvm2019] Using REST wrapper from plugin
[2020-04-03T19:46:34,867][INFO ][ ] [txvm2019] using discovery type [zen] and seed hosts providers [settings]
[2020-04-03T19:46:35,768][INFO ][ ] [txvm2019] initialized
[2020-04-03T19:46:35,768][INFO ][ ] [txvm2019] starting ...
[2020-04-03T19:46:35,923][INFO ][ ] [txvm2019] publish_address {172.17.0.1:9300}, bound_addresses {0.0.0.0:9300}
[2020-04-03T19:46:35,932][INFO ][ ] [txvm2019] bound or publishing to a non-loopback address, enforcing bootstrap checks
ERROR: [2] bootstrap checks failed
[1]: max number of threads [2048] for user [elasticsearch] is too low, increase to at least [4096]
[2]: the default discovery settings are unsuitable for production use; at least one of [discovery.seed_hosts, discovery.seed_providers, cluster.initial_master_nodes] must be configured
[2020-04-03T19:46:35,978][INFO ][ ] [txvm2019] stopping ...
[2020-04-03T19:46:36,012][INFO ][ ] [txvm2019] stopped
[2020-04-03T19:46:36,012][INFO ][ ] [txvm2019] closing ...
[2020-04-03T19:46:36,032][INFO ][ ] [txvm2019] closed
3、错误：cluster.initial_master_nodes] must be configured
解决方法：
在elasticsearch的config目录下，修改配置文件，将下面的配置加入到该配置文件中：
ip替换host1等，多节点请添加多个ip地址，单节点可写按默认来
#配置以下三者，最少其一
#[discovery.seed_hosts, discovery.seed_providers, cluster.initial_master_nodes]
cluster.initial_master_nodes: ["node-1"] #这里的node-1为node-name配置的值
[2020-04-03T19:51:41,427][DEBUG][ ] [txvm2019] Using REST wrapper from plugin
[2020-04-03T19:51:41,799][INFO ][ ] [txvm2019] using discovery type [zen] and seed hosts providers [settings]
[2020-04-03T19:51:42,729][INFO ][ ] [txvm2019] initialized
[2020-04-03T19:51:42,729][INFO ][ ] [txvm2019] starting ...
[2020-04-03T19:51:42,890][INFO ][ ] [txvm2019] publish_address {172.17.0.1:9300}, bound_addresses {0.0.0.0:9300}
[2020-04-03T19:51:42,900][INFO ][ ] [txvm2019] bound or publishing to a non-loopback address, enforcing bootstrap checks
ERROR: [1] bootstrap checks failed
[1]: the default discovery settings are unsuitable for production use; at least one of [discovery.seed_hosts, discovery.seed_providers, cluster.initial_master_nodes] must be configured
4、删除数据时错误："reason":"Wildcard expressions or all indices are not allowed"
解决方法：
删除所有索引时
curl -X DELETE "http://localhost:9200/*"
或者
curl -X DELETE "localhost:9200/_all"
为了防止误删除，
可以设置 属性 action.destructive_requires_name为true，
禁止使用通配符或_all删除索引，
必须使用名称或别名才能删除该索引。
修改为false即可删除所有
action.destructive_requires_name: false
{"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"Wildcard expressions or all indices are not allowed"}],"type":"illegal_argument_exception","reason":"Wildcard expressions or all indices are not allowed"},"status":400}
5、创建索引错误：The mapping definition cannot be nested under a type [_doc] unless include_type_name is set to true.
解决方法：
修改为：
{
"settings": {
"number_of_shards": 3,
"number_of_replicas": 2
},
"mappings": {
"properties": {
"commodity_id": {
"type": "long"
},
"commodity_name": {
"type": "text"
},
"picture_url": {
"type": "text"
},
"price": {
"type": "double"
}
}
}
}
出现这个的原因是，elasticsearch7默认不在支持指定索引类型，默认索引类型是_doc，如果想改变，则配置include_type_name: true 即可(这个没有测试，官方文档说的，无论是否可行，建议不要这么做，因为elasticsearch8后就不在提供该字段)。
{
"error": {
"root_cause": [ {
"type": "illegal_argument_exception",
"reason": "The mapping definition cannot be nested under a type [_doc] unless include_type_name is set to true."
}],
"type": "illegal_argument_exception",
"reason": "The mapping definition cannot be nested under a type [_doc] unless include_type_name is set to true."
},
"status": 400
}
6、聚合查询时错误："Fielddata is disabled on text fields by default. ...."
解决方法：
经过查找验证后发现出现该错误是因为之后，Elasticsearch对排序、聚合所依据的字段用单独的数据结构(fielddata)缓存到内存里了，但是在text字段上默认是禁用的，这样做的目的是为了节省内存空间。所以如果需要进行聚合操作，需要单独开启。执行以下代码(city为相关text的字段名称)：
PUT myindex/_mapping
{
"properties": {
"city": {
"type": "text",
"fielddata": true
}
}
}
"caused_by": {
"type": "illegal_argument_exception",
"reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [city] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead.",
"caused_by": {
"type": "illegal_argument_exception",
"reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [city] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead."
}
}