Hi,
First let me complement the hbase developers for their work in
offering this very useful tool to the world.
We are running hbase-0.1.1 on top of hadoop-0.16.3, starting the hbase
daemon from an "hbase" user account and the hadoop daemon and have
observed this "feature". We are running hbase in a separate "hadoop"
user account and hadoop in it's own "hadoop" user account on a single
machine.
When we try to start up hbase, we see this error message in the log:
2008-05-06 12:09:02,845 ERROR org.apache.hadoop.hbase.HMaster: Can not
start master
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
Method)
at
sun
.reflect
.NativeConstructorAccessorImpl
.newInstance(NativeConstructorAccessorImpl.java:39)
at
sun
.reflect
.DelegatingConstructorAccessorImpl
.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:494)
at org.apache.hadoop.hbase.HMaster.doMain(HMaster.java:3329)
at org.apache.hadoop.hbase.HMaster.main(HMaster.java:3363)
Caused by: org.apache.hadoop.ipc.RemoteException:
org.apache.hadoop.fs.permission.AccessControlException: Superuser
privilege is required
... (etc)
We get this no matter whether the "hadoop-site.xml" includes any one
of these properties, or none of them:
<property>
<name>dfs.web.ugi</name>
<value>webuser,webgroup</value>
<final>true</final>
</property>
<property>
<name>dfs.web.ugi</name>
<value>webuser,supergroup</value>
<final>true</final>
</property>
<property>
<name>dfs.web.ugi</name>
<value>hadoop,supergroup</value>
<final>true</final>
</property>
On the other hand, if we run hbase in the hadoop user account instead
of it's own user account, we have no problems.
Finally, if we include this property in the "hadoop-site.xml" file to
turn off the hdfs file system permission feature:
<property>
<name>dfs.permissions</name>
<value>false</value>
<final>true</final>
</property>
we can start up hbase in it's own user account or in the hadoop user
account.
This almost seems like it has something to do with interaction between
Linux ext3 user and group permissions and the hdfs user and group
permissions system. We may have missed comments in the mail lists,
FAQs or elsewhere addressing this problem, our apologies if we have.
Congrats and thanks again on a very nice system.
