10.艾玛, Datanode也启动不了了?
找到log:
Caused by: java.net.UnknownHostException: Invalid host name: local host is: (unknown); destination host is: “maste1”:8031; java.net.
UnknownHostException; For more details see: http://wiki.apache.org/hadoop/UnknownHost
解决的方法:
找到hadoop配置文件yarn-site.xml改正配置信息例如以下. 
依旧启动不了?
解决的方法:
清空master1, master2 上的name里的数据,删除current文件夹,rm -rf current
清空slave1,slave2上的data01里的数据,删除current文件夹,rm -rf current
在主master1上name格式化, hdfs namenode -format
启动hdfs: ./start-all.sh
奏效!!赞!!!
11.命令#netstat -atln是做什么的?
答: 查看网络port信息的.
-a (all)显示所有选项。默认不显示LISTEN相关
-t (tcp)仅显示tcp相关选项
-n 拒绝显示别名。能显示数字的所有转化成数字。
-l 仅列出有在 Listen (监听) 的服務状态
參考链接http://www.cnblogs.com/ggjucheng/archive/2012/01/08/2316661.html 
12.Tomcat配置web账号password:
答:配置web管理帐号
改动文件conf/tomcat-users.xml，在tomcat-users元素中加入帐号password。须要指定角色.
# vi /usr/local/tomcat/server/conf/tomcat-users.xml
<tomcat-users>
<user name="admin" password="admin" roles="admin-gui,manager-gui" />
</tomcat-users>參考资料:http://blog.csdn.net/gyming/article/details/36060843
Solr安装參考资料:
http://www.linuxidc.com/Linux/2014-05/101443.htm
http://www.656463.com/article/IbiInu.htm
13. 查看 solr的logging会出现：
19:44:42 WARN SolrResourceLoader Can’t find (or read) directory to add to classloader: ../../../contrib/extraction/lib (resolved as: /home/solr_home/collection1/../../../contrib/extraction/lib).
这种警告；事实上这是由于找不到 相应的jar包造成的。
在/home/solr_home/collection1/conf/solrconfig.xml 中原有的配置文件为：
<lib dir="../../../contrib/extraction/lib" regex=".*\.jar" />
<lib dir="../../../dist/" regex="solr-cell-\d.*\.jar" />
<lib dir="../../../contrib/clustering/lib/" regex=".*\.jar" />
<lib dir="../../../dist/" regex="solr-clustering-\d.*\.jar" />
<lib dir="../../../contrib/langid/lib/" regex=".*\.jar" />
<lib dir="../../../dist/" regex="solr-langid-\d.*\.jar" />
<lib dir="../../../contrib/velocity/lib" regex=".*\.jar" />
<lib dir="../../../dist/" regex="solr-velocity-\d.*\.jar" />
<!-- If a 'dir' option (with or without a regex) is used and nothing
is found that matches, a warning will be logged.
-->
<lib dir="/non/existent/dir/yields/warning" />这个是警告信息
解决的方法: 能够将 solr-4.3.1\文件夹下的 contrib 和 dist 复制到 /home/solr_home/collection1/conf 以下就能够了
然后改动上面的配置文件/home/solr_home/collection1/conf/solrconfig.xml就可以。
<lib dir="conf/contrib/extraction/lib" regex=".*\.jar" />
<lib dir="conf/dist/" regex="solr-cell-\d.*\.jar" />
<lib dir="conf/contrib/clustering/lib/" regex=".*\.jar" />
<lib dir="conf/dist/" regex="solr-clustering-\d.*\.jar" />
<lib dir="conf/contrib/langid/lib/" regex=".*\.jar" />
<lib dir="conf/dist/" regex="solr-langid-\d.*\.jar" />
<lib dir="conf/contrib/velocity/lib" regex=".*\.jar" />
<lib dir="conf/dist/" regex="solr-velocity-\d.*\.jar" />
<!-- If a 'dir' option (with or without a regex) is used and nothing
is found that matches, a warning will be logged.
-->
<lib dir="/non/existent/dir/yields/warning" /> 14.Solr中怎样新建core?
參考资料:http://blog.csdn.net/clj198606061111/article/details/21288499/
15 solr完美安装參考链接?
http://www.656463.com/article/IbiInu.htm
http://my.oschina.net/liuxundemo/blog/208236