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

     

  • manatee's avatar
    manatee
    Level 6
    9 years ago

    yes. both master/media server and client are unix machines so i use consistent case.

  • sdo's avatar
    sdo
    Moderator
    9 years ago
    Pure guess... ...try on master: bprdreq -rereadconfig
  • Marianne's avatar
    Marianne
    Level 6
    9 years ago

    It is difficult to try and assist you if you cannot show us actual names (including Host Properties screenshot).

    Another look at your nslookup commands seems that reverse lookup only resolves FQDN -  clientA.acme.com but you have only clientA in NBU policy.

    Please check DNS to ensure that shortname and FQDN is resolved in nslookup commands.

    If you change NBU policy now to clientA.acme.com, you are going to experience issues with restores, as the 2 hostnames will be stored in different images folders on the master.

  • manatee's avatar
    manatee
    Level 6
    9 years ago

    i have already confirmed that everything resolves fine from the OS:

    1. the ntp client is working fine; it will not work if it can't resolve properly any hostname (be it FQDN or not)
    2. my post above shows "nslookup" from the OS is able to resolve by name and by IP
    3. i did change the NBU policy from using just the hostname to using FQDN and NBU still can't resolve
    4. i have also cleared the host cache severals times

     

  • Marianne's avatar
    Marianne
    Level 6
    9 years ago

    Your example shows that DNS resolves by FQDN: clientA.acme.com

    You have configured NBU for shortname: clientA

    clientA.acme.com != clientA

  • Tape_Archived's avatar
    Tape_Archived
    Moderator
    9 years ago

    Can you please check if you have any specific setting for these clients??

    Go to : Hosts Properties => Clients => clientA.acme.com

     

  • manatee's avatar
    manatee
    Level 6
    9 years ago

    but that's how name resolving works from the OS. if the OS can resolve why not the application? unless the application has its own concept of networking then i should not be concentrating at the OS level.

    i'm just confuse why NBU uses "/etc/hosts" only and not a DNS server.

    in Hosts Properties => Clients => clientA.acme.com the client is showing. as for the specific settings you are referring to i'm not sure what you want. i created a test policy, with clientA (or clientA.acme.com) as the client and that's it.

  • Marianne's avatar
    Marianne
    Level 6
    9 years ago
    The moment you can show us screenshots of real life config and tests, we will be able to see what is going wrong in your environment. NBU works fine with DNS. We have many customers using DNS only. Good luck.
  • manatee's avatar
    manatee
    Level 6
    9 years ago

    as much as i would like to share the actual screenshots, due to security reasons i have to mask the actual hostnames and ip addresses. i hope you understand. however, all that i posts are exactly what i see here except the change in hostnames and ip addresses.

    i checked the client properties as suggested by Genericus and everything checks out: long name everywhere:

    1. in client's "bp.conf" it uses FQDN
    2. in client's "/etc/hosts" it uses FQDN with alias
    3. in my DNS server it uses FQDN with alias
    4. in NetBackup Management, then Host Properties, then select Clients it uses FQDN in client name

     

    again, master have connection to client only IF i use "/etc/hosts" and not when i use my DNS server.

  • manatee's avatar
    manatee
    Level 6
    9 years ago

    and i just happen to have RHEL6. it is set to "1" alright will try it tomorrow after the DBAs are done with their patching work.

    yeah i initially started with "/etc/hosts" but it is getting unwildy it's hard to maintain.

    thanks for the link!