最后发现是VPS Provider aliyun 造成的，只开放了22、80443等常用端口.

At last I find it's caused by the VPS Provider aliyun, it only open some common port such 22, 80,443.

我需要登录阿里云VPS管理页面，打开5044，让VPS Provider绕过5044端口.

I need to login to aliyun VPS management page, and open 5044 to make VPS Provider bypass the 5044 port.

*注:* 附件:我在使用 ELK 配置 filebeat 时遇到的一些其他问题.

*Note: * Attachment: some other issues I encountered when config filebeat with ELK.

**问题1:**连接回退失败(async(tcp://ip:5044)): dial tcp ip:5044: connect: connection denied

**Issue 1: ** Failed to connect to backoff(async(tcp://ip:5044)): dial tcp ip:5044: connect: connection refused

2019-08-26T10:25:41.955+0800    ERROR   pipeline/output.go:100  Failed to connect to backoff(async(tcp://example.com:5044)): dial tcp xx.xx.xx.xx:5044: connect: connection refused
2019-08-26T10:25:41.955+0800    INFO    pipeline/output.go:93   Attempting to reconnect to backoff(async(tcp://example:5044)) with 2 reconnect attempt(s)

问题 2: 无法发布事件，原因是:write tcp ip:46890->ip:5044: write: connection reset by peer

Issue 2: Failed to publish events caused by: write tcp ip:46890->ip:5044: write: connection reset by peer

2019-08-26T10:28:32.274+0800    ERROR   logstash/async.go:256   Failed to publish events caused by: write tcp xx.xx.xx.xx:46890->xx.xx.xx.xx:5044: write: connection reset by peer
2019-08-26T10:28:33.311+0800    ERROR   pipeline/output.go:121  Failed to publish events: write tcp xx.xx.xx.xx:46890->xx.xx.xx.xx:5044: write: connection reset by peer

问题 3: Filebeat 错误:lumberjack 协议错误和 Logstash 错误:OPENSSL_internal:WRONG_VERSION_NUMBER

Issue 3: Filebeat error: lumberjack protocol error and Logstash error: OPENSSL_internal:WRONG_VERSION_NUMBER

Filebeat 日志错误，

Filebeat log error,

2019-08-26T08:49:09.505+0800    INFO    pipeline/output.go:95   Connecting to backoff(async(tcp://example.com:5044))
2019-08-26T08:49:09.588+0800    INFO    pipeline/output.go:105  Connection to backoff(async(tcp://example.com:5044)) established
2019-08-26T08:49:09.605+0800    ERROR   logstash/async.go:256   Failed to publish events caused by: lumberjack protocol error
2019-08-26T08:49:09.606+0800    ERROR   logstash/async.go:256   Failed to publish events caused by: client is not connected

Logstash 日志，

Logstash log,

[INFO ] 2019-08-26 08:49:29.444 [defaultEventExecutorGroup-4-2] BeatsHandler - [local: 0.0.0.0:5044, remote: undefined] Handling exception: javax.net.ssl.SSLHandshakeException: error:100000f7:SSL routines:OPENSSL_internal:WRONG_VERSION_NUMBER
[WARN ] 2019-08-26 08:49:29.445 [nioEventLoopGroup-2-7] DefaultChannelPipeline - An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
io.netty.handler.codec.DecoderException: javax.net.ssl.SSLHandshakeException: error:100000f7:SSL routines:OPENSSL_internal:WRONG_VERSION_NUMBER
        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:472) ~[netty-all-4.1.30.Final.jar:4.1.30.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:278) ~[netty-all-4.1.30.Final.jar:4.1.30.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) ~[netty-all-4.1.30.Final.jar:4.1.30.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) ~[netty-all-4.1.30.Final.jar:4.1.30.Final]
        ...

这三个问题都是未配置造成的，这里是可行的配置，

All the three issues are caused by miss configuration, here is the workable config,

logstash 版本，

logstash version,

/usr/share/logstash/bin/logstash -V
logstash 7.3.1

filebeat 版本，

filebeat version,

/usr/share/filebeat/bin/filebeat version
filebeat version 7.3.1 (amd64), libbeat 7.3.1 [a4be71b90ce3e3b8213b616adfcd9e455513da45 built 2019-08-19 19:30:50 +0000 UTC]

logstash 配置文件 /etc/logstash/conf.d/beat.conf

logstash conf file /etc/logstash/conf.d/beat.conf

input {
  beats {
    port => 5044
    ssl => true
    ssl_certificate_authorities => "/etc/pki/tls/certs/logstash-forwarder.crt"
    ssl_certificate => "/etc/pki/tls/certs/logstash-forwarder.crt"
    ssl_key => "/etc/pki/tls/private/logstash-forwarder.key"
    ssl_verify_mode => "peer"
  }
}

output {
  elasticsearch {
    hosts => "http://127.0.0.1:9200"
    manage_template => false
    index => "%{[@metadata][beat]}-%{[@metadata][version]}-%{+YYYY.MM.dd}"
    document_type => "%{[@metadata][type]}"
  }
}

filebeat 配置文件 /etc/filebeat/filebeat.yml

filebeat conf file /etc/filebeat/filebeat.yml

#=========================== Filebeat inputs =============================

filebeat.inputs:

# Each - is an input. Most options can be set at the input level, so
# you can use different inputs for various configurations.
# Below are the input specific configurations.

- type: log

  # Change to true to enable this input configuration.
  enabled: true

  # Paths that should be crawled and fetched. Glob based paths.
  paths:
    - /data/error_logs/Log_error_201908


#----------------------------- Logstash output --------------------------------
output.logstash:
  # The Logstash hosts
  hosts: ["example.com:5044"]

  # Optional SSL. By default is off.
  # List of root certificates for HTTPS server verifications
  ssl.certificate_authorities: ["/etc/pki/tls/certs/logstash-forwarder.crt"]

  # Certificate for SSL client authentication
  ssl.certificate: "/etc/pki/tls/certs/logstash-forwarder.crt"

  # Client Certificate Key
  ssl.key: "/etc/pki/tls/private/logstash-forwarder.key"