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Topic
  • 4 replies
  • Latest Post - ‏2013-06-11T21:15:05Z by mduff
mduff
mduff
35 Posts

Pinned topic Node resolution: DNS or Config

‏2013-06-05T16:50:49Z |

I do realize that both addresses should be the same, but in the case that they are not:

When a node tries to contact a manager, which IP address does it use: the one that DNS resolves or the one that is recorded in the GPFS configuration?

  • YannickBergeron
    YannickBergeron
    35 Posts

    Re: Node resolution: DNS or Config

    ‏2013-06-06T13:49:51Z  

    probably depends on your name resolution order

    On AIX, it's configured in /etc/netsvc.conf

  • mduff
    mduff
    35 Posts

    Re: Node resolution: DNS or Config

    ‏2013-06-09T21:19:01Z  

    probably depends on your name resolution order

    On AIX, it's configured in /etc/netsvc.conf

    Thank you Yannick. 

    In this case the DNS entry and hosts file are the same.  I'm asking which is read first between the host lookup and GPFS config.

    From a mmsdrfs file:

    %%home%%:20_MEMBER_NODE::1:1:gs0:172.31.51.8:node0.company.com:manager::::::node0.company.com:node0:1218:3.4.0.15:Linux:Q:0::10.83.5.8:E::server::
    %%home%%:20_MEMBER_NODE::2:2:gs1:172.31.51.9:node1.company.com:manager::::::node1.company.com:node1:1218:3.4.0.15:Linux:Q:0::10.83.5.9:E::server::

    Is the lookup done for the hostname or is the ip address used?  They should be the same, but we are trying to rule out a potential issue.

     

  • YannickBergeron
    YannickBergeron
    35 Posts

    Re: Node resolution: DNS or Config

    ‏2013-06-10T11:33:08Z  
    • mduff
    • ‏2013-06-09T21:19:01Z

    Thank you Yannick. 

    In this case the DNS entry and hosts file are the same.  I'm asking which is read first between the host lookup and GPFS config.

    From a mmsdrfs file:

    %%home%%:20_MEMBER_NODE::1:1:gs0:172.31.51.8:node0.company.com:manager::::::node0.company.com:node0:1218:3.4.0.15:Linux:Q:0::10.83.5.8:E::server::
    %%home%%:20_MEMBER_NODE::2:2:gs1:172.31.51.9:node1.company.com:manager::::::node1.company.com:node1:1218:3.4.0.15:Linux:Q:0::10.83.5.9:E::server::

    Is the lookup done for the hostname or is the ip address used?  They should be the same, but we are trying to rule out a potential issue.

     

    As I said, it depends of your local configuration
    On AIX, it's in /etc/netsvc.conf

    # egrep -v "^#" /etc/netsvc.conf
    hosts=local,bind

    this would prefer the entry from /etc/hosts before the DNS
    but if the config would be:

    # egrep -v "^#" /etc/netsvc.conf
    hosts=bind,local

    the DNS would be preferred over the local entries

  • mduff
    mduff
    35 Posts

    Re: Node resolution: DNS or Config

    ‏2013-06-11T21:15:05Z  

    As I said, it depends of your local configuration
    On AIX, it's in /etc/netsvc.conf

    # egrep -v "^#" /etc/netsvc.conf
    hosts=local,bind

    this would prefer the entry from /etc/hosts before the DNS
    but if the config would be:

    # egrep -v "^#" /etc/netsvc.conf
    hosts=bind,local

    the DNS would be preferred over the local entries

    I'm sorry Yannick, I must not be making myself clear.  Remove the host resolution process out of the equation.

    Does GPFS use the IP address in the mmsdrfs file or does it lookup the hostname?