The purpose of makedns is to setup a domain name server where it is run. If you don't want that, I would suggest you manually setup your MN to use the external name server and configure /etc/hosts with nodes you don't want in the external server with makehosts. We have many clusters that do that because having name resolution from /etc/hosts is much faster.
Lissa K. Valletta 8-3/B10 Poughkeepsie, NY 12601 (tie 293) 433-3102 From: Josh Nielsen <[email protected]> To: xCAT Users Mailing list <[email protected]>, Date: 04/02/2014 06:18 PM Subject: Re: [xcat-user] Makedns wiping out DNS records As Christopher notes, it is an additional attack surface. Also I would like to not have to worry about an additional named instance running in my network which I am not using. If it is not currently possible to prevent the local named daemon on the MN from starting when makedns is run, can that behavior be changed in a future xCAT version if you want an external master only? I'm still curious as to whether the /var/named/ directory would have any zone files locally on the MN in the case where named is running locally but you are pushing updates to an external DNS server, or whether it only pushes zone entries out to the DNS server specified with 'makedns -e' (as it should). -Josh On Mon, Mar 31, 2014 at 8:17 PM, Xiao Peng Wang <[email protected]> wrote: Enable the local DNS on xCAT MN does not hurt anything except the cpu/memory to run makedns in your case, right? Thanks Best Regards ---------------------------------------------------------------------- Wang Xiaopeng (王晓朋) IBM China System Technology Laboratory Tel: 86-10-82453455 Email: [email protected] Address: 28,ZhongGuanCun Software Park,No.8 Dong Bei Wang West Road, Haidian District Beijing P.R.China 100193 Inactive hide details for Josh Nielsen ---2014/04/01 00:00:13--->"By default, makedns sets up the named service and updates theJosh Nielsen ---2014/04/01 00:00:13--->"By default, makedns sets up the named service and updates the DNS records on the local system (man From: Josh Nielsen <[email protected]> To: xCAT Users Mailing list <[email protected]>, [email protected], Date: 2014/04/01 00:00 Subject: Re: [xcat-user] Makedns wiping out DNS records >"By default, makedns sets up the named service and updates the DNS records on the local system (management node). If the -e flag is specified, it will also update the DNS records on any external DNS server that is listed in the /etc/resolv.conf on the management node." Interesting, so even if I use an external DNS server I can't "get rid of/turn off" the DNS service on the MN? I suppose I could do a 'chkconfig named off' but makedns starts the named daemon anyway when you run it (I think). I want to make the external server the sole Master DNS server, and every other server its slave (I have only two other slave DNS servers, which are my Service Nodes). I'm in the same boat as Christopher who noted "One kink I think we've noticed there is that even with makedns -e xCAT seems to start up bind on the local system which isn't what we want at all." I also would prefer the local BIND/named daemon to not start at all, and rather make the external DNS the sole master. However, as you indicated makedns by default (which I'm assuming is a behavior that can't be changed [yet]?) sets up the local named service when it is run. Can xCAT be modified to accommodate the "external only master" scenario? Regards, Josh Nielsen On Thu, Mar 27, 2014 at 12:38 PM, Lissa Valletta <[email protected]> wrote: It is saying if your site has an external name server and you want to use it , you need to add that external name server into the /etc/resolv.conf file. You also have to add the correct nameservers in the site table before you run makedns. This is the manual part. chdef -t site nameservers=50.1.2.254 for example. The makedns -e will take the external nameservers that you have listed in /etc/resolv.conf and update their DNS records, assuming you have the authority to change that server. >From man makedns By default, makedns sets up the named service and updates the DNS records on the local system (management node). If the -e flag is specified, it will also update the DNS records on any external DNS server that is listed in the /etc/resolv.conf on the management node. (Assuming the external DNS server can recognize the xCAT key as authentication.) Lissa K. Valletta 8-3/B10 Poughkeepsie, NY 12601 (tie 293) 433-3102 Inactive hide details for Josh Nielsen ---03/26/2014 03:15:37 PM---Sorry to revive this, but I have a question about external D Josh Nielsen ---03/26/2014 03:15:37 PM---Sorry to revive this, but I have a question about external DNS since I am thinking of trying it now. From: Josh Nielsen <[email protected]> To: xCAT Users Mailing list <[email protected]>, Date: 03/26/2014 03:15 PM Subject: Re: [xcat-user] Makedns wiping out DNS records Sorry to revive this, but I have a question about external DNS since I am thinking of trying it now. On the Cluster Name Resolution wiki page ( http://sourceforge.net/apps/mediawiki/xcat/index.php?title=Cluster_Name_Resolution ) under 'Option #2: Use a DNS That is Outside of the Cluster' it says: "If you already have a DNS on your site network and you want to use that for your cluster node names too, you can point all of the nodes to it. You must ensure that your nodes have IP connectivity to the DNS, and you must manually configure your DNS with the node hostnames and IP addresses." What does it mean that "you must manually configure" the hostnames and IP addresses? Does 'makedns -e' not do that for you, just like it would if DNS were running locally on the MN itself by just parsing /etc/hosts and adding/pushing it to the (remote) DNS zone files for you? In my case I may even be migrating my existing DNS zone files and "/etc/named.conf" config onto a new VM and bring up DNS there and just add any new hosts. But I would be surprised if makedns -e doesn't add the hostnames and IPs for you. Can anyone who has used the external DNS option with xCAT speak to that? Thanks, Josh On Thu, Jan 16, 2014 at 5:13 PM, Christopher Samuel < [email protected]> wrote: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 17/01/14 04:00, Josh Nielsen wrote: > If it just something with our installation or does makedns do this > foe other people as well? FWIW we do not run DNS on the management nodes at all, we have 4 separate xCAT built clusters (3 HPC clusters and 1 for our GPFS/TSM infrastructure and our BG/Q service and front ends) and so to let them all populate DNS with a single, consistent view we have two external DNS servers that they all send updates to with "makedns -e". One kink I think we've noticed there is that even with makedns -e xCAT seems to start up bind on the local system which isn't what we want at all. Good luck! Chris - -- Christopher Samuel Senior Systems Administrator VLSCI - Victorian Life Sciences Computation Initiative Email: [email protected] Phone: +61 (0)3 903 55545 http://www.vlsci.org.au/ http://twitter.com/vlsci -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlLYZ4sACgkQO2KABBYQAh8pwACfSEi4RePX5F2hG5E1AtrAdy77 PtMAni1KEwsOM/az4z0U7o4aZZOEuO/+ =fPWd -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. 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