hive创建数据库的错误，小白笔记

hive创建数据库的错误

最近开始要复习一下hive，考完研一年基本上没碰大数据了，可是一上来注定不能顺顺利利的，启动hive，输入“create database test;”回车。

FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. MetaException(message:java.lang.IllegalArgumentException: java.net.UnknownHostException: server.node2)

好像我的主机名也不是什么server.node2，这个是哪里冒出来的，想了一下，好像当时把Hadoop的安装配置直接拷贝到这台主机上来的，所以主机名解析才会出问题，于是找到core-site.xml，果然：

        
        
                fs.defaultFS
                hdfs://server.node2:9000
        
        
        
                hadoop.tmp.dir
                /home/hadoop/hadoop-2.4.1/tmp
    

于是，赶紧把server.node2改成了现在的主机名（主机名需要在hosts文件里面配置映射关系）。
再次运行hive，创建数据库，继续报错：

FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. MetaException(message:Got exception: java.net.ConnectException Call From mini1/127.0.0.1 to server.mini1:9000 failed on connection exception: java.net.ConnectException: 拒绝连接; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused)

为什么会拒绝连接呢？hive创建数据库需要MapReduce，那应该是需要启动一下HDFS，启动HDFS，又报了下面的错误：

warning:: ssh: Could not resolve hostname warning:: Name or service not known
have: ssh: Could not resolve hostname have: Name or service not known
HotSpot(TM): ssh: Could not resolve hostname HotSpot(TM): Name or service not known
library: ssh: Could not resolve hostname library: Name or service not known
You: ssh: Could not resolve hostname You: No address associated with hostname
VM: ssh: Could not resolve hostname VM: Name or service not known
loaded: ssh: Could not resolve hostname loaded: Name or service not known
The: ssh: Could not resolve hostname The: Name or service not known
stack: ssh: Could not resolve hostname stack: Name or service not known
which: ssh: Could not resolve hostname which: Name or service not known
Client: ssh: Could not resolve hostname Client: Name or service not known
have: ssh: Could not resolve hostname have: Name or service not known
guard.: ssh: Could not resolve hostname guard.: Name or service not known
fix: ssh: Could not resolve hostname fix: Name or service not known
VM: ssh: Could not resolve hostname VM: Name or service not known

网上查了一下，需要在/etc/profile文件中加入：

export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native
export HADOOP_OPTS=-Djava.library.path=$HADOOP_HOME/lib

以上代码直接复制粘贴就可以，不需要做任何修改，我猜测，应该是linux的版本问题吧，不管了，反正这块解决了。
这样，HDFS就正常启动了，接着再启动hive，创建数据库也正常了。