Forum Discussion

manatee's avatar
manatee
Level 6
9 years ago

NBU has to use "hosts" file?

NBU 7.6.0.3

so i was configuring all my Solaris machines to use my Active Directory DNS server because of ntp client configuration requirements. ntp work done and working fine. name lookups via Active Directory DNS also working fine without me having to always manually update each server's "/etc/hosts" file.

however, today i found that NBU master can't seem to resolve names when done this way. i have to use the old way by entering the client's hostname and ip address in the "/etc/hosts" file. then and only then did the master server able to resolve and find the client.

why is this so? how can we move NBU to the 21st century and make use of a DNS server?

7.6
Backup and Recovery
NetBackup
Solaris
  • Genericus's avatar
    Genericus
    9 years ago

    OK, so now check the system files and make sure it is set to use DNS before local files.

     

    Personally - I have had this same problem before, and since it DOES connect using /etc/hosts, it should not be a networking issue. I just added that one host to /etc/hosts and did not waste any more time on it.

     

    Just a thought - 

    Mostly this happens with multi-NIC systems, where traffic comes in one NIC and for some reason, returns via another path. Master definitely sees a difference sending to client-backup and getting a response via client instead. I have had a problem before on a linux box, I had to do this:

    Here is the official link describing how to change RHEL6 and RHEL7 to support loose asymmetrical routing:

    https://access.redhat.com/solutions/53031

     

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  • Genericus's avatar
    Genericus
    Moderator
    9 years ago

    100% confident that this is network/OS DNS issue. Agree with Marianne - you need to confirm that you can communicate at the OS level forward and backward, with the same host name, using DNS. 

  • Genericus's avatar
    Genericus
    Moderator
    9 years ago

    One thing you can also check is the client properties: There are THREE places that MUST match (or at least NOT be different)

    From java admin console, expand NetBackup Management, then Host Properties, then select Clients, in the right window, select your client - it should polulate as it connects.

    Once it is connected, right click and select Properties, or menu Actions, Properties.

    A window should pop up - check these tabs:

    Main Properties in left window - what is the Host name in the right side?

    Universal Setting Tab - is there anything in the Use specified network interface: field? IT CAN BE BLANK, as long as the client name matches the NIC you use.

    Client Name - what is the Client Name field?

     

    Some of my server admins cannot seem to match these, short name vs long name, case mis matches, client vs client-backup - all these cause issues.

     

    You generally will not go wrong making them all the same - as long as they match the client in the policy...

     

     

  • Genericus's avatar
    Genericus
    Moderator
    9 years ago

    OK, so now check the system files and make sure it is set to use DNS before local files.

     

    Personally - I have had this same problem before, and since it DOES connect using /etc/hosts, it should not be a networking issue. I just added that one host to /etc/hosts and did not waste any more time on it.

     

    Just a thought - 

    Mostly this happens with multi-NIC systems, where traffic comes in one NIC and for some reason, returns via another path. Master definitely sees a difference sending to client-backup and getting a response via client instead. I have had a problem before on a linux box, I had to do this:

    Here is the official link describing how to change RHEL6 and RHEL7 to support loose asymmetrical routing:

    https://access.redhat.com/solutions/53031

     

  • Marianne's avatar
    Marianne
    Level 6
    9 years ago
    NBU works 100% with DNS. Just ensure that DNS reverse lookup is also enabled. If you can use nslookup to resolve hostname to IP and IP to hostname, then NBU will work with DNS. Just remember to clear host cache after OS-level changes are made.
  • manatee's avatar
    manatee
    Level 6
    9 years ago

    yes i can resolve both ways. still if i remove the entry in "/etc/hosts" the master/media server gives "(48) client hostname could not be found".

    [root@manager bin]# ./bpclntcmd -clear_host_cache
    [root@manager bin]# ./bpclntcmd -clear_host_cache
    [root@manager bin]# ./bpclntcmd -clear_host_cache
    [root@manager bin]# ./bpclntcmd -clear_host_cache
    [root@manager bin]# ./bpclntcmd -clear_host_cache
    [root@manager bin]# nslookup 192.168.1.10
    Server:         192.168.1.50
    Address:       192.168.1.50#53

    10.1.168.192.in-addr.arpa        name = clientA.acme.com.

    [root@manager bin]# nslookup clientA
    Server:         192.168.1.50
    Address:       192.168.1.50#53

    Name:   clientA.acme.com
    Address: 192.168.1.10

     

  • manatee's avatar
    manatee
    Level 6
    9 years ago

    ok i found this command parameter is failing:

    [root@manager bin]# ./bpclntcmd -hn clientA
    client hostname could not be found
    alter client: clientA : not found. (48)

    but if i do the resolving thru the OS it resolves fine as noted in my previous post.

    so how does one troubleshoot this "bpclntcmd" command?

  • manatee's avatar
    manatee
    Level 6
    9 years ago

    found the problem! at least from the master/media server side:

    #hosts:     db files nisplus nis dns
    hosts:      files dns
    ipnodes:     files dns

     

    in "/etc/nsswitch.conf" there was a missing colon after the "ipnodes" keyword. after i inserted the colon, "./bpclntcmd -hn clientA" works as expected.

    still from NBU console it gives the same error 48. doing "bpclntcmd -pn" from the client side produces no output.

  • sdo's avatar
    sdo
    Moderator
    9 years ago
    As Marianne suggested... ...try this on the master and all media servers: bpclntcmd -clear_host_cache
  • manatee's avatar
    manatee
    Level 6
    9 years ago

    did that many times over. i only have one master server which is also a media server.

    it's resolving fine now from master/media server but from the NBU../Host Properties/Clients it still gives the same error message.

    without restarting the services, anything else i should check?