FAQ
Hi,

I am trying to setup CHD4 on a small cluster of 4 machines with a cloud
provider.

The install fails with following message.Can anyone shed soem light why
this is failing??

Detecting Cloudera Manager Server...
BEGIN host -t PTR 31.221.34.100
100.34.221.31.in-addr.arpa domain name pointer
31-221-34-100.cust-31.exponential-e.net.
END (0)
using 31-221-34-100.cust-31.exponential-e.net as scm server hostname
BEGIN ping -c 1 31-221-34-100.cust-31.exponential-e.net
END (2)
could not contact scm server, giving up
Reverting changes...
rollback started
Removing package repositories...
Uninstalled.
rollback completed
closing logging file descriptor
ping: unknown host 31-221-34-100.cust-31.exponential-e.net

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  • Philip Langdale at Jun 28, 2012 at 4:50 pm
    Hi Pavan,

    It seems like the way DNS works with your cloud provider is unusual. What
    you're seeing is a basic sanity test that ensures the CM agents can talk to
    the management server. It obtains the IP address from the ssh connection,
    and then does a reverse DNS lookup against it to get a hostname to use
    for future connections to the server. That reverse DNS lookup is returning
    a result, but that result is not, it self, actually a valid DNS name.

    Perhaps surprisingly, I can sit here at my machine and do the lookup:

    # host -t PTR 31.221.34.100
    100.34.221.31.in-addr.arpa domain name pointer
    31-221-34-100.cust-31.exponential-e.net.
    #host 31-221-34-100.cust-31.exponential-e.net
    Host 31-221-34-100.cust-31.exponential-e.net not found: 3(NXDOMAIN)

    That doesn't seem like a sane thing for them to be doing. I would ask them
    how they
    expect DNS to work with their hosts.

    --phil


    On 28 June 2012 05:20, Pavan Keerthi wrote:

    Hi,

    I am trying to setup CHD4 on a small cluster of 4 machines with a cloud
    provider.

    The install fails with following message.Can anyone shed soem light why
    this is failing??

    Detecting Cloudera Manager Server...
    BEGIN host -t PTR 31.221.34.100
    100.34.221.31.in-addr.arpa domain name pointer 31-221-34-100.
    cust-31.exponential-e.net.
    END (0)
    using 31-221-34-100.cust-31.exponential-e.net as scm server hostname
    BEGIN ping -c 1 31-221-34-100.cust-31.exponential-e.net
    END (2)
    could not contact scm server, giving up
    Reverting changes...
    rollback started
    Removing package repositories...
    Uninstalled.
    rollback completed
    closing logging file descriptor
    ping: unknown host 31-221-34-100.cust-31.exponential-e.net
  • Pavan Keerthi at Jun 28, 2012 at 9:48 pm
    Hi Phil,

    After posting this ,I dig in more into this problem and realised my mistake
    was running this from my local vm which nodes cant reach back. So I moved
    Manager to one of nodes in Microsoft Azure cloud,but it still had same
    error. I checked their documentation and realised their DNS service does
    not provide reverse PTR record.

    What are my options here? EC2?


    On Thursday, June 28, 2012 1:20:32 PM UTC+1, Pavan Keerthi wrote:

    Hi,

    I am trying to setup CHD4 on a small cluster of 4 machines with a cloud
    provider.

    The install fails with following message.Can anyone shed soem light why
    this is failing??

    Detecting Cloudera Manager Server...
    BEGIN host -t PTR 31.221.34.100
    100.34.221.31.in-addr.arpa domain name pointer
    31-221-34-100.cust-31.exponential-e.net.
    END (0)
    using 31-221-34-100.cust-31.exponential-e.net as scm server hostname
    BEGIN ping -c 1 31-221-34-100.cust-31.exponential-e.net
    END (2)
    could not contact scm server, giving up
    Reverting changes...
    rollback started
    Removing package repositories...
    Uninstalled.
    rollback completed
    closing logging file descriptor
    ping: unknown host 31-221-34-100.cust-31.exponential-e.net
  • Philip Langdale at Jun 28, 2012 at 10:39 pm
    Hi Pavan,

    Why not run all the nodes inside the exponential-e cloud? Then the DNS
    would work
    correctly. ec2 will work, but there are tricks you need to be aware of
    there as well, to
    ensure the best experience. The main ones are around private vs public IPs
    and the fact
    that the private IP changes whenever you restart the instance. We're
    working to streamline
    that experience in a future release, but it remains a manual process so far.

    I'm surprised Azure doesn't include working DNS.

    --phil


    On 28 June 2012 14:48, Pavan Keerthi wrote:

    Hi Phil,

    After posting this ,I dig in more into this problem and realised my
    mistake was running this from my local vm which nodes cant reach back. So I
    moved Manager to one of nodes in Microsoft Azure cloud,but it still had
    same error. I checked their documentation and realised their DNS service
    does not provide reverse PTR record.

    What are my options here? EC2?


    On Thursday, June 28, 2012 1:20:32 PM UTC+1, Pavan Keerthi wrote:

    Hi,

    I am trying to setup CHD4 on a small cluster of 4 machines with a cloud
    provider.

    The install fails with following message.Can anyone shed soem light why
    this is failing??

    Detecting Cloudera Manager Server...
    BEGIN host -t PTR 31.221.34.100
    100.34.221.31.in-addr.arpa domain name pointer 31-221-34-100.cust-31.**
    exponential-e.net <http://31-221-34-100.cust-31.exponential-e.net>.
    END (0)
    using 31-221-34-100.cust-31.**exponential-e.net<http://31-221-34-100.cust-31.exponential-e.net>as scm server hostname
    BEGIN ping -c 1 31-221-34-100.cust-31.**exponential-e.net<http://31-221-34-100.cust-31.exponential-e.net>

    END (2)
    could not contact scm server, giving up
    Reverting changes...
    rollback started
    Removing package repositories...
    Uninstalled.
    rollback completed
    closing logging file descriptor
    ping: unknown host 31-221-34-100.cust-31.**exponential-e.net<http://31-221-34-100.cust-31.exponential-e.net>

  • Pavan Keerthi at Jun 28, 2012 at 10:48 pm
    Sorry.Should have been clear.exponential-e cloud is some junk dns assigned
    by Virtual box to VM :) .Originally I setup SSH from virtual box vm to my
    nodes on cloud,but only later realised nodes cannot connect back to this
    local VM on PC.

    I was trying out Microsoft Azure VM cloud as I have some free usage tier
    available from them.
    On Thursday, June 28, 2012 1:20:32 PM UTC+1, Pavan Keerthi wrote:

    Hi,

    I am trying to setup CHD4 on a small cluster of 4 machines with a cloud
    provider.

    The install fails with following message.Can anyone shed soem light why
    this is failing??

    Detecting Cloudera Manager Server...
    BEGIN host -t PTR 31.221.34.100
    100.34.221.31.in-addr.arpa domain name pointer
    31-221-34-100.cust-31.exponential-e.net.
    END (0)
    using 31-221-34-100.cust-31.exponential-e.net as scm server hostname
    BEGIN ping -c 1 31-221-34-100.cust-31.exponential-e.net
    END (2)
    could not contact scm server, giving up
    Reverting changes...
    rollback started
    Removing package repositories...
    Uninstalled.
    rollback completed
    closing logging file descriptor
    ping: unknown host 31-221-34-100.cust-31.exponential-e.net
  • Ravi Paruchuri at Mar 9, 2013 at 3:11 am
    Please make sure you have ICMP is open.

    Once it sets the SCM server hostname, it tries to PING the hostname. So,
    make sure ICMP is open all the way.

    If you use the default on AWS, ICMP is open but not for any other security
    groups you select.

    Thanks,
    Ravi
    On Thursday, June 28, 2012 6:48:27 PM UTC-4, Pavan Keerthi wrote:

    Sorry.Should have been clear.exponential-e cloud is some junk dns assigned
    by Virtual box to VM :) .Originally I setup SSH from virtual box vm to my
    nodes on cloud,but only later realised nodes cannot connect back to this
    local VM on PC.

    I was trying out Microsoft Azure VM cloud as I have some free usage tier
    available from them.
    On Thursday, June 28, 2012 1:20:32 PM UTC+1, Pavan Keerthi wrote:

    Hi,

    I am trying to setup CHD4 on a small cluster of 4 machines with a cloud
    provider.

    The install fails with following message.Can anyone shed soem light why
    this is failing??

    Detecting Cloudera Manager Server...
    BEGIN host -t PTR 31.221.34.100
    100.34.221.31.in-addr.arpa domain name pointer
    31-221-34-100.cust-31.exponential-e.net.
    END (0)
    using 31-221-34-100.cust-31.exponential-e.net as scm server hostname
    BEGIN ping -c 1 31-221-34-100.cust-31.exponential-e.net
    END (2)
    could not contact scm server, giving up
    Reverting changes...
    rollback started
    Removing package repositories...
    Uninstalled.
    rollback completed
    closing logging file descriptor
    ping: unknown host 31-221-34-100.cust-31.exponential-e.net

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groupscm-users @
categorieshadoop
postedJun 28, '12 at 12:20p
activeMar 9, '13 at 3:11a
posts6
users3
websitecloudera.com
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