转载自:http://blog.csdn.net/viproc/article/details/7570866
情景描述: 按照hadoop手册,搭建Single Node. 启动hadoop时 #./start-all.sh 报错: #######################################################
localhost: Unrecognized option: -jvm localhost: Could not create the Java virtual machine. ###################################################### 环境: 服务器:RHEL4.7_x86_64 内存:512M hadoop版本:hadoop-0.20.203.0rc1.tar.gz java版本:jdk-6u25-linux-x64.bin 解决: 可以修改的地方有两个 第一个(次要的):/usr/local/hadoop/conf/hadoop-env.sh 修改参数: export HADOOP_HEAPSIZE=256 #默认值为1000M,为Java虚拟机占用的内存的大小 第二个(主要的): 查看/usr/local/hadoop/bin/hadoop源码: #################################################################### if [[ $EUID -eq 0 ]]; then HADOOP_OPTS="$HADOOP_OPTS -jvm server $HADOOP_DATANODE_OPTS" else HADOOP_OPTS="$HADOOP_OPTS -server $HADOOP_DATANODE_OPTS" fi #################################################################### 如果以root身份启动,则hadoop启动java虚拟机时,会带上-jvm参数。 不同的java版本,启动参数可能会不一致,由此导致以上问题。 其他解释 (详细见链接地址: http://mail-archives.apache.org/mod_mbox/hadoop-hdfs-user/201105.mbox /%3CBANLkTinm3q4EAo=GkeMjG67ZnXXRLRV+yw@mail.gmail.com%3E): ####################################################################> I think, that code is there for jsvc. If you run hadoop in secure mode, it > executes this path. There is nothing wrong in -jvm option since it meant for > jsvc. > > In case of secure mode, jsvc process runs as root and invokes the datanode > process as hdfs user (or any other configured user). > But it seems there is a bug in the code, if you run as root in non-secured > mode this issue can trigger. > ####################################################################
因此, 新建一个hadoop用户, 重新初始化操作:#./hadoop namenode -format 再次启动hadoop: #./start-all.sh 正常。 补充: 修改JAVA_HEAP_MAX的大小: # vi bin/hadoop JAVA_HEAP_MAX=-Xmx1000m 输出结果: ##############################################################################################################
[hadoop@localhost bin]$ ./start-all.sh starting namenode, logging to /usr/local/hadoop/bin/../logs/hadoop-hadoop-namenode-localhost.out localhost: starting datanode, logging to /usr/local/hadoop/bin/../logs/hadoop-hadoop-datanode-localhost.out localhost: starting secondarynamenode, logging to /usr/local/hadoop/bin/../logs/hadoop-hadoop-secondarynamenode-localhost.out starting jobtracker, logging to /usr/local/hadoop/bin/../logs/hadoop-hadoop-jobtracker-localhost.out localhost: starting tasktracker, logging to /usr/local/hadoop/bin/../logs/hadoop-hadoop-tasktracker-localhost.out####################################################################################