We have an entire doc on name resolution also I would not make it a common practice to use XCATBYPASS mode. Running with the xcatd is much more secure and some things do not work well in XCATBYPASS mode. https://sourceforge.net/apps/mediawiki/xcat/index.php?title=Cluster_Name_Resolution
Lissa K. Valletta 8-3/B10 Poughkeepsie, NY 12601 (tie 293) 433-3102 From: Josh Nielsen <jniel...@hudsonalpha.org> To: xCAT Users Mailing list <xcat-user@lists.sourceforge.net>, Date: 01/16/2014 12:03 PM Subject: [xcat-user] Makedns wiping out DNS records Regardless of the version of xCAT we have used in the past, my coworkers and I have noticed that running "makedns" with any following options can be dangerous for us, because something happens where it will wipe out all the records in DNS. If we run "makedns" with no options generally any new nodes that have been added to /etc/hosts will be parsed and added appropriately. Maybe I am misunderstanding what happens when the command is run. Here is a recent example. My entry for a new node "xcat-serv1" for some reason didn't have the reverse lookup from the IP in the DNS file for that subnet (db.10.20), and so I decided to try to remove just the DNS entry for that node and then re-add it. Here is what I ran: ---- # makedns -d xcat-serv1 Handling xcat-serv1 in /etc/hosts. Getting reverse zones, this may take several minutes for a large cluster. Completed getting reverse zones. Updating zones. Completed updating zones. Updating DNS records, this may take several minutes for a large cluster. Completed updating DNS records. ---- Then I ran it with the "-n" parameter to re-add that node (with XCATBYPASS=1): ---- # export XCATBYPASS=1 [root@x3650-head01 centos]# makedns -n xcat-serv1 Unrecognized escape \h passed through at /opt/xcat/lib/perl/xCAT/zvmUtils.pm line 2408. Subroutine handled_commands redefined at /opt/xcat/lib/perl/xCAT_plugin/ hosts.pm line 28. Subroutine delnode redefined at /opt/xcat/lib/perl/xCAT_plugin/hosts.pm line 33. Subroutine addnode redefined at /opt/xcat/lib/perl/xCAT_plugin/hosts.pm line 58. Subroutine build_line redefined at /opt/xcat/lib/perl/xCAT_plugin/hosts.pm line 117. Subroutine addotherinterfaces redefined at /opt/xcat/lib/perl/xCAT_plugin/ hosts.pm line 182. Subroutine delotherinterfaces redefined at /opt/xcat/lib/perl/xCAT_plugin/ hosts.pm line 209. Subroutine add_hosts_content redefined at /opt/xcat/lib/perl/xCAT_plugin/ hosts.pm line 234. Subroutine process_request redefined at /opt/xcat/lib/perl/xCAT_plugin/ hosts.pm line 305. Subroutine writeout redefined at /opt/xcat/lib/perl/xCAT_plugin/hosts.pm line 511. Subroutine donics redefined at /opt/xcat/lib/perl/xCAT_plugin/hosts.pm line 545. Subroutine getIPdomain redefined at /opt/xcat/lib/perl/xCAT_plugin/hosts.pm line 801. Handling xcat-serv1 in /etc/hosts. Getting reverse zones, this may take several minutes for a large cluster. Completed getting reverse zones. Stopping named: . [ OK ] Updating zones. Completed updating zones. Restarting named Restarting named complete Updating DNS records, this may take several minutes for a large cluster. Completed updating DNS records. DNS setup is completed .... .... ---- When I did an 'ls' in /var/named many records were missing and the ones still left we virtually empty except one entry for the headnode: BEFORE: # ls /var/named data db.10.29 db.10.40 db.127.0.0 db.172.26.41 db.172.29 db.192.168.100 db.haig db.morgan.haib.org.jnl db.10.29.jnl db.10.60 db.172.20 db.172.26.42 db.172.30 db.cache db.morgan slaves db.10.20 db.10.30 db.10.60.jnl db.172.26.40 db.172.26.43 db.172.40 db.haib db.morgan.haib.org AFTER: # ls /var/named data db.10.20.jnl db.10.29.jnl db.10.30.jnl db.10.40.jnl db.10.60.jnl db.172.26.41 db.172.26.43 db.morgan.haib.org.jnl db.10.20 db.10.29 db.10.30 db.10.40 db.10.60 db.172.26.40 db.172.26.42 db.morgan.haib.org slaves As you can see several files are missing, Luckily I made a full backup yesterday and was able to restore the old files. >From /var/log/messages you can see the initial deletion message for "xcat-serv1": ---- Jan 16 10:32:55 x3650-head01 named[8249]: client 10.20.0.1#56080: updating zone '40.10.IN-ADDR.ARPA/IN': adding an RR at '11.102.40.10.IN-ADDR.ARPA' PTR Jan 16 10:32:55 x3650-head01 named[8249]: client 10.20.0.1#56080: updating zone '40.10.IN-ADDR.ARPA/IN': adding an RR at '7.101.40.10.IN-ADDR.ARPA' PTR Jan 16 10:32:55 x3650-head01 named[8249]: client 10.20.0.1#56080: updating zone '40.10.IN-ADDR.ARPA/IN': adding an RR at '10.102.40.10.IN-ADDR.ARPA' PTR Jan 16 10:32:55 x3650-head01 named[8249]: client 10.20.0.1#56080: updating zone '40.10.IN-ADDR.ARPA/IN': adding an RR at '27.102.40.10.IN-ADDR.ARPA' PTR Jan 16 10:32:55 x3650-head01 named[8249]: client 10.20.0.1#56080: updating zone '40.10.IN-ADDR.ARPA/IN': adding an RR at '33.101.40.10.IN-ADDR.ARPA' PTR Jan 16 10:32:55 x3650-head01 named[8249]: client 10.20.0.1#56080: updating zone '40.10.IN-ADDR.ARPA/IN': adding an RR at '1.102.40.10.IN-ADDR.ARPA' PTR Jan 16 10:32:55 x3650-head01 named[8249]: client 10.20.0.1#56080: updating zone Then for the makedens -a xcat-serv you actually see it update EVERY ZONE: Jan 16 10:32:42 x3650-head01 named[8249]: client 10.20.0.1#43788: updating zone '30.10.IN-ADDR.ARPA/IN': adding an RR at '1.50.30.10.IN-ADDR.ARPA' PTR Jan 16 10:32:42 x3650-head01 named[8249]: client 10.20.0.1#43788: updating zone '30.10.IN-ADDR.ARPA/IN': adding an RR at '4.50.30.10.IN-ADDR.ARPA' PTR Jan 16 10:32:42 x3650-head01 named[8249]: client 10.20.0.1#43788: updating zone '30.10.IN-ADDR.ARPA/IN': adding an RR at '2.2.30.10.IN-ADDR.ARPA' PTR Jan 16 10:32:42 x3650-head01 named[8249]: client 10.20.0.1#43788: updating zone '30.10.IN-ADDR.ARPA/IN': adding an RR at '3.50.30.10.IN-ADDR.ARPA' PTR Jan 16 10:32:42 x3650-head01 named[8249]: client 10.20.0.1#43788: updating zone '30.10.IN-ADDR.ARPA/IN': adding an RR at '1.2.30.10.IN-ADDR.ARPA' PTR Jan 16 10:32:42 x3650-head01 named[8249]: client 10.20.0.1#43788: updating zone '30.10.IN-ADDR.ARPA/IN': adding an RR at '2.50.30.10.IN-ADDR.ARPA' PTR .... [long list] ---- After this is when I listed and saw files missing and most of the records empty. My guess is the "-d" wiped out all the records somehow and not just "xcat-serv1". Either that or the makedns -a deleted all the records in order to recreate them. But why would it affect ALL the records when I specifically typed "xcat-serv1"? I tried a plain "makedns" with no options after this and it also says "adding an RR at" (is that even the expected message?) for all the IPs and zones but nothing actually gets added. What is up with that? If it just something with our installation or does makedns do this foe other people as well? Regards, Josh ------------------------------------------------------------------------------ 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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