FAQ
Hey everyone,

I am quite new to using hadoop. I have got the config and everything working
perfect with 1 namenode/jobtracker, 1 datanode, 1 secondary data node.
However, Keeping the config the same i just added a slave to the list in the
conf/slaves files and tried running the cluster. This resulted in me getting
permission denied when i put in the password for ssh in. The ssh
passwordless login is not working for some reason. its only the data nodes
that are giving trouble however, the secondary name node is starting up
without a hitch even though that pass is the last one to be entered.
Any ideas/suggestions anyone might have.

Thanks

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  • Alex Loddengaard at Jul 10, 2009 at 5:34 pm
    This sounds like a SSH key issue. I'm going to assume that you're invoking
    the start-*.sh scripts from the NameNode. On the NameNode, you'll want to
    run "ssh-keygen -t rsa" as the user that runs Hadoop (probably "hadoop").
    This should create two files: ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub. scp the
    *.pub file to all of your other nodes, and store that file as
    ~/.ssh/authorized_keys on each node, including the NameNode. Give
    ~/.ssh/authorized_keys 600 permissions. You should be good to go. I
    recommend testing this stuff before running the start-*.sh scripts.

    You may always want to look at our (Cloudera's) RPMs and DEBs. They
    simplify the installation of Hadoop and give you init scripst to start all
    the daemons. Then you can avoid the start-*.sh scripts. <
    http://www.cloudera.com/hadoop>

    Hope this helps.

    Alex
    On Fri, Jul 10, 2009 at 9:19 AM, Divij Durve wrote:

    Hey everyone,

    I am quite new to using hadoop. I have got the config and everything
    working
    perfect with 1 namenode/jobtracker, 1 datanode, 1 secondary data node.
    However, Keeping the config the same i just added a slave to the list in
    the
    conf/slaves files and tried running the cluster. This resulted in me
    getting
    permission denied when i put in the password for ssh in. The ssh
    passwordless login is not working for some reason. its only the data nodes
    that are giving trouble however, the secondary name node is starting up
    without a hitch even though that pass is the last one to be entered.
    Any ideas/suggestions anyone might have.

    Thanks
  • Divij Durve at Jul 11, 2009 at 5:58 am
    ok thanks for the advce ill have a look into this and get back to u on
    sunday. Really appreciate it. However, Im baffled at to y it would do this
    only when there are 2 data nodes and when there is 1 it works fine any ideas
    on that one? Im not saying this solution doesnt work im just asking coz im
    curious and trying to understand it properly. Also im running start-dfs.sh
    or start-all.sh
    On Fri, Jul 10, 2009 at 1:34 PM, Alex Loddengaard wrote:

    This sounds like a SSH key issue. I'm going to assume that you're invoking
    the start-*.sh scripts from the NameNode. On the NameNode, you'll want to
    run "ssh-keygen -t rsa" as the user that runs Hadoop (probably "hadoop").
    This should create two files: ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub. scp the
    *.pub file to all of your other nodes, and store that file as
    ~/.ssh/authorized_keys on each node, including the NameNode. Give
    ~/.ssh/authorized_keys 600 permissions. You should be good to go. I
    recommend testing this stuff before running the start-*.sh scripts.

    You may always want to look at our (Cloudera's) RPMs and DEBs. They
    simplify the installation of Hadoop and give you init scripst to start all
    the daemons. Then you can avoid the start-*.sh scripts. <
    http://www.cloudera.com/hadoop>

    Hope this helps.

    Alex
    On Fri, Jul 10, 2009 at 9:19 AM, Divij Durve wrote:

    Hey everyone,

    I am quite new to using hadoop. I have got the config and everything
    working
    perfect with 1 namenode/jobtracker, 1 datanode, 1 secondary data node.
    However, Keeping the config the same i just added a slave to the list in
    the
    conf/slaves files and tried running the cluster. This resulted in me
    getting
    permission denied when i put in the password for ssh in. The ssh
    passwordless login is not working for some reason. its only the data nodes
    that are giving trouble however, the secondary name node is starting up
    without a hitch even though that pass is the last one to be entered.
    Any ideas/suggestions anyone might have.

    Thanks

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groupcommon-user @
categorieshadoop
postedJul 10, '09 at 4:19p
activeJul 11, '09 at 5:58a
posts3
users2
websitehadoop.apache.org...
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Divij Durve: 2 posts Alex Loddengaard: 1 post

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