Re: Namenode not listening for remote connections to port 9000
Hmmm - I checked all the /etc/hosts files, and they're all fine. Then I switched the conf/hadoop-site.xml to specify ip addresses instead of host names. Then oddly enough it starts working... Now the funny thing is this: It's fine ssh-ing to the correct machines to start up datanodes, but when the datanode thread tries to make the connection back to the namenode (from within a java app I assume) it doesn't resolve the names correctly. Just looking at this makes me want to think that the namenode does its ssh work in some non-java way, actually checking the hosts file, while the datanode does its thing in Java, which doesn't seem to check the hosts file. Could this be some Java funnyness that it's not checking the hosts file? Now there's just one sucky thing about my setup: If I change my file with a list of datanodes (dfs.hosts property) to also have IP addresses instead of hostnames, then it fails. So parts of my config is specifying hostnames, and other parts are specifying IP addresses. Oh well - for development purposes this is good enough, 'cause out in the real world I won't be using the hosts file to string it all together. Thanks for the responses. Mark Kerzner wrote: I had a problem that it listened only on 8020, even though I told it to use 9000 On Fri, Feb 13, 2009 at 7:50 AM, Norbert Burger norbert.bur...@gmail.comwrote: On Fri, Feb 13, 2009 at 8:37 AM, Steve Loughran ste...@apache.org wrote: Michael Lynch wrote: Hi, As far as I can tell I've followed the setup instructions for a hadoop cluster to the letter, but I find that the datanodes can't connect to the namenode on port 9000 because it is only listening for connections from localhost. In my case, the namenode is called centos1, and the datanode is called centos2. They are centos 5.1 servers with an unmodified sun java 6 runtime. fs.default.name takes a URL to the filesystem. such as hdfs://centos1:9000/ If the machine is only binding to localhost, that may mean DNS fun. Try a fully qualified name instead (fs.default.name is defined in conf/hadoop-site.xml, overriding entries from conf/hadoop-default.xml). Also, check your /etc/hosts file on both machines. Could be that you have a incorrect setup where both localhost and the namenode hostname (centos1) are aliased to 127.0.0.1. Norbert
Re: Namenode not listening for remote connections to port 9000
Michael Lynch wrote: Hi, As far as I can tell I've followed the setup instructions for a hadoop cluster to the letter, but I find that the datanodes can't connect to the namenode on port 9000 because it is only listening for connections from localhost. In my case, the namenode is called centos1, and the datanode is called centos2. They are centos 5.1 servers with an unmodified sun java 6 runtime. fs.default.name takes a URL to the filesystem. such as hdfs://centos1:9000/ If the machine is only binding to localhost, that may mean DNS fun. Try a fully qualified name instead
Re: Namenode not listening for remote connections to port 9000
On Fri, Feb 13, 2009 at 8:37 AM, Steve Loughran ste...@apache.org wrote: Michael Lynch wrote: Hi, As far as I can tell I've followed the setup instructions for a hadoop cluster to the letter, but I find that the datanodes can't connect to the namenode on port 9000 because it is only listening for connections from localhost. In my case, the namenode is called centos1, and the datanode is called centos2. They are centos 5.1 servers with an unmodified sun java 6 runtime. fs.default.name takes a URL to the filesystem. such as hdfs://centos1:9000/ If the machine is only binding to localhost, that may mean DNS fun. Try a fully qualified name instead (fs.default.name is defined in conf/hadoop-site.xml, overriding entries from conf/hadoop-default.xml). Also, check your /etc/hosts file on both machines. Could be that you have a incorrect setup where both localhost and the namenode hostname (centos1) are aliased to 127.0.0.1. Norbert
Re: Namenode not listening for remote connections to port 9000
I had a problem that it listened only on 8020, even though I told it to use 9000 On Fri, Feb 13, 2009 at 7:50 AM, Norbert Burger norbert.bur...@gmail.comwrote: On Fri, Feb 13, 2009 at 8:37 AM, Steve Loughran ste...@apache.org wrote: Michael Lynch wrote: Hi, As far as I can tell I've followed the setup instructions for a hadoop cluster to the letter, but I find that the datanodes can't connect to the namenode on port 9000 because it is only listening for connections from localhost. In my case, the namenode is called centos1, and the datanode is called centos2. They are centos 5.1 servers with an unmodified sun java 6 runtime. fs.default.name takes a URL to the filesystem. such as hdfs://centos1:9000/ If the machine is only binding to localhost, that may mean DNS fun. Try a fully qualified name instead (fs.default.name is defined in conf/hadoop-site.xml, overriding entries from conf/hadoop-default.xml). Also, check your /etc/hosts file on both machines. Could be that you have a incorrect setup where both localhost and the namenode hostname (centos1) are aliased to 127.0.0.1. Norbert
