利用开源日志收集软件fluentd收集日志到HDFS文件系统中

说明：本来研究开源日志的系统是flume，后来发现配置比较麻烦，网上搜索到fluentd也是开源的日志收集系统，配置简单多了，性能不错，所以就改研究这个东东了！官方主页，大家可以看看：fluentd.org，支持300+的plugins，应该是不错的！

fluentd是通过hadoop中的webHDFS与HDFS进行通信的，所以在配置fluentd时，一定要保证webHDFS能正常通信，和通过webHDFS写数据到hdfs中！

原理图如下：

webHDFS的相关配置与测试，请看这篇文章：http://shineforever.blog.51cto.com/1429204/1585942

安装环境大致说明：

1）fluentd和hadoop中的namenode要安装到一台物理机器上；

2）os版本：rhel 5.7 64位

3）hadoop版本：1.2.1

4）jdk1.7.0_67

5）ruby版本：ruby 2.1.2p95 

1.安装前的准备工作，安装ruby，因为fluentd是ruby开发的：

yum install openssl-devel zlib-devel gcc gcc-c++ make autoconf readline-devel curl-devel expat-devel gettext-devel

卸载系统自带ruby版本：

yum erase ruby ruby-libs ruby-mode ruby-rdoc ruby-irb ruby-ri ruby-docs

通过源码安装ruby：

wget -c http://cache.ruby-lang.org/pub/ruby/2.1/ruby-2.1.2.tar.gz

然后解压包，编译，把ruby安装到目录 /usr/local/ruby即可，然后设置profile环境变量。

测试ruby：

[root@node1 install]# ruby -v

ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]

出现以上字段，代表ruby安装成功。

2.fluentd安装：

fluentd有源码安装，gem安装或者rpm方式安装三种方式；

本文采用rpm的安装方式官方文档已经帮我们写好了脚本,直接执行就行了：

curl -L http://toolbelt.treasuredata.com/sh/install-redhat-td-agent2.sh | sh

安装成功以后，启动脚本是：/etc/init.d/td-agent start

配置文件路径是：/etc/td-agent/

[root@node1 install]# cd /etc/td-agent/

You have new mail in /var/spool/mail/root

[root@node1 td-agent]# pwd

/etc/td-agent

[root@node1 td-agent]# ls

logrotate.d  plugin  prelink.conf.d  td-agent.conf  

3.利用gem安装fluentd插件fluent-plugin-webhdfs

1）由于国内防火墙block了ruby源，请更换gem的源：

[root@node1 bin]# td-agent-gem source --remove https://ruby.taobao.org/

https://ruby.taobao.org/ removed from sources

[root@node1 bin]# td-agent-gem source -a https://ruby.taobao.org/      

https://ruby.taobao.org/ added to sources

2）安装插件：

td-agent-gem  install fluent-plugin-webhdfs

查看gem的安装列表：

td-agent-gem list

*** LOCAL GEMS ***

bigdecimal (1.2.4)

bundler (1.7.7)

cool.io (1.2.4)

fluent-mixin-config-placeholders (0.3.0)

fluent-mixin-plaintextformatter (0.2.6)

fluent-plugin-webhdfs (0.4.1)

fluentd (0.12.0.pre.2)

http_parser.rb (0.6.0)

io-console (0.4.2)

json (1.8.1)

ltsv (0.1.0)

minitest (4.7.5)

msgpack (0.5.9)

psych (2.0.5)

rake (10.1.0)

rdoc (4.1.0)

sigdump (0.2.2)

string-scrub (0.0.5)

test-unit (2.1.2.0)

thread_safe (0.3.4)

tzinfo (1.2.2)

tzinfo-data (1.2014.10)

uuidtools (2.1.5)

webhdfs (0.6.0)

yajl-ruby (1.2.1)

4）配置flunetd，加载fluent-plugin-webhdfs 模块；

加入以下字段：

vim /etc/td-agent/td-agent.conf

重启td-agent服务；

5）设置hdfs相关配置：

创建log目录

 hadoop fs -mkdir /log

赋予log目录权限为777，如果不赋予，数据写不进去，官方文档没有说明，测试了好久才发现！

hadoop fs -chmod 777 /log

6）再次重启td-agent服务，开始测试，测试命令如下：

curl -X POST -d 'json={"json":"message"}' http://172.16.41.151:8888/hdfs.access.test

这时就发现hadoop里面文件有变化了！

安装配置过程中的报错：

1）

2014-12-03 15:56:12 +0800 [warn]: failed to communicate hdfs cluster, path: /log/20141203_15/access.log.node1.test.com

2014-12-03 15:56:12 +0800 [warn]: temporarily failed to flush the buffer. next_retry=2014-12-03 15:56:28 +0800 error_class="WebHDFS::ClientError" error="{\"RemoteException\":{\"exception\":\"IllegalArgumentException\",\"javaClassName\":\"java.lang.IllegalArgumentException\",\"message\":\"n must be positive\"}}" instance=23456251808160

  2014-12-03 15:56:12 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/webhdfs-0.5.5/lib/webhdfs/client_v1.rb:313:in `request'

  2014-12-03 15:56:12 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/webhdfs-0.5.5/lib/webhdfs/client_v1.rb:231:in `operate_requests'

  2014-12-03 15:56:12 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/webhdfs-0.5.5/lib/webhdfs/client_v1.rb:45:in `create'

  2014-12-03 15:56:12 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluent-plugin-webhdfs-0.3.1/lib/fluent/plugin/out_webhdfs.rb:189:in `rescue in send_data'

  2014-12-03 15:56:12 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluent-plugin-webhdfs-0.3.1/lib/fluent/plugin/out_webhdfs.rb:186:in `send_data'

  2014-12-03 15:56:12 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluent-plugin-webhdfs-0.3.1/lib/fluent/plugin/out_webhdfs.rb:205:in `write'

  2014-12-03 15:56:12 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/buffer.rb:296:in `write_chunk'

  2014-12-03 15:56:12 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/buffer.rb:276:in `pop'

  2014-12-03 15:56:12 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/output.rb:311:in `try_flush'

  2014-12-03 15:56:12 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/output.rb:132:in `run'

出现以上情况，是你的hdfs文件系统有问题，不能写数据等等，请单独测试hdfs的是否运行正常！

2）

2014-12-04 14:44:55 +0800 [warn]: failed to communicate hdfs cluster, path: /log/20141204_14/access.log.node1.test.com

2014-12-04 14:44:55 +0800 [warn]: temporarily failed to flush the buffer. next_retry=2014-12-04 14:45:30 +0800 error_class="WebHDFS::IOError" error="{\"RemoteException\":{\"exception\":\"AccessControlException\",\"javaClassName\":\"org.apache.hadoop.security.AccessControlException\",\"message\":\"org.apache.hadoop.security.AccessControlException: Permission denied: user=webuser, access=WRITE, inode=\\\"\\\":hadoop:supergroup:rwxr-xr-x\"}}" instance=23456251808060

  2014-12-04 14:44:55 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/webhdfs-0.5.5/lib/webhdfs/client_v1.rb:317:in `request'

  2014-12-04 14:44:55 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/webhdfs-0.5.5/lib/webhdfs/client_v1.rb:242:in `operate_requests'

  2014-12-04 14:44:55 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/webhdfs-0.5.5/lib/webhdfs/client_v1.rb:45:in `create'

  2014-12-04 14:44:55 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluent-plugin-webhdfs-0.3.1/lib/fluent/plugin/out_webhdfs.rb:189:in `rescue in send_data'

  2014-12-04 14:44:55 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluent-plugin-webhdfs-0.3.1/lib/fluent/plugin/out_webhdfs.rb:186:in `send_data'

  2014-12-04 14:44:55 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluent-plugin-webhdfs-0.3.1/lib/fluent/plugin/out_webhdfs.rb:205:in `write'

  2014-12-04 14:44:55 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/buffer.rb:296:in `write_chunk'

  2014-12-04 14:44:55 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/buffer.rb:276:in `pop'

  2014-12-04 14:44:55 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/output.rb:311:in `try_flush'

  2014-12-04 14:44:55 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/output.rb:132:in `run'

2014-12-04 14:45:31 +0800 [warn]: failed to communicate hdfs cluster, path: /log/20141204_14/access.log.node1.test.com

2014-12-04 14:45:31 +0800 [warn]: temporarily failed to flush the buffer. next_retry=2014-12-04 14:46:26 +0800 error_class="WebHDFS::IOError" error="{\"RemoteException\":{\"exception\":\"AccessControlException\",\"javaClassName\":\"org.apache.hadoop.security.AccessControlException\",\"message\":\"org.apache.hadoop.security.AccessControlException: Permission denied: user=webuser, access=WRITE, inode=\\\"\\\":hadoop:supergroup:rwxr-xr-x\"}}" instance=23456251808060

  2014-12-04 14:45:31 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/webhdfs-0.5.5/lib/webhdfs/client_v1.rb:317:in `request'

  2014-12-04 14:45:31 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/webhdfs-0.5.5/lib/webhdfs/client_v1.rb:242:in `operate_requests'

  2014-12-04 14:45:31 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/webhdfs-0.5.5/lib/webhdfs/client_v1.rb:45:in `create'

  2014-12-04 14:45:31 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluent-plugin-webhdfs-0.3.1/lib/fluent/plugin/out_webhdfs.rb:189:in `rescue in send_data'

  2014-12-04 14:45:31 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluent-plugin-webhdfs-0.3.1/lib/fluent/plugin/out_webhdfs.rb:186:in `send_data'

  2014-12-04 14:45:31 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluent-plugin-webhdfs-0.3.1/lib/fluent/plugin/out_webhdfs.rb:205:in `write'

  2014-12-04 14:45:31 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/buffer.rb:296:in `write_chunk'

  2014-12-04 14:45:31 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/buffer.rb:276:in `pop'

  2014-12-04 14:45:31 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/output.rb:311:in `try_flush'

  2014-12-04 14:45:31 +0800 [warn]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.55/lib/fluent/output.rb:132:in `run'

出现以上情况，一般是你的hdfs没有设置好权限，把存放日志的hdfs目录chmod 777，就可以了！

如果日志写入hdfs正常，日志显示的是：2014-12-04 14:48:40 +0800 [warn]: retry succeeded. instance=23456251808060