Arif, yes, it makes sense. It's kind of a new requirement, because current xcat dns implementation can not meet this case and running command on SN directly normally is not recommanded though it works for you :)
To Bruce, for the implementation to set up an individual dns server on SN, I think this could be something like site.disjointdhcps, it's default to "0", means to set up dns server on MN and dns forwarder cache on SNs, if it's set to "1" means to set up individual dns servers on MN and SNs. while if the SN does not have external network connection, then maybe it does not make sense to set the site.forwarders to the dns server on SN? Another potential issue might be passing /etc/hosts content from MN to SNs via XML in the scaling cluster, this seems not a xcat strategy - SN should get the resources from database on a file. I'm now investigating if there is any method inside dns to make syncup between dns servers, for example, dig, or rndc, or something else, if so, we can keep the logic to set up dns server on MN, then make syncup on SN without /etc/hosts, will try more. Thx. Jing Arif Ali <[email protected]> 2013/10/26 02:02 Please respond to xCAT Users Mailing list <[email protected]> To xCAT Users Mailing list <[email protected]>, cc Subject Re: [xcat-user] makedns issue Bruce/Jing, Let me elaborate on another scenario, where having multiple nameservers, and primarily SN being the choice, I run makehosts and makedns on all service nodes, I was in essence making the SN as a temporary failover for as many services that xCAT MN was providing. The only service not being to failover were the commands that were commands that were tied to the database, which is most of them. Actually one of our customers due to the nature of the remote access, both the customer and ourselves accidentally rebooted the MN, and jobs happily were able to resolve the names due to the fact the SN was the shadow host for the scheduler and had a named configuration. We tend to find that MN tends to be also the login node, so to have a fail-over like this can be imperative I hope that makes sense. -- Arif Ali IRC: arif-ali at freenode LinkedIn: http://uk.linkedin.com/in/arifali On 25 October 2013 18:01, Bruce M Potter <[email protected]> wrote: Sun Jing, Arif's requirement is valid and i have heard it many times, so we need to come up with a solution. Maybe we need an option on makedns to configure all of the SN DNS instances the same way we configure the MN DNS: have all of the mappings from /etc/hosts (from the MN), and be configured with site.forwarders. In this mode makedns would be similar to makedhcp, in that it would spawn an xcatd request to each of the SNs to configure the DNS on the SNs. Thoughts? Other ideas? Bruce Potter STSM, Linux & AIX Cluster Development, IBM, Poughkeepsie, NY Email: [email protected] Phone: external: 845-433-7073, internal: TL 293-7073 Jing CDL Sun ---10/25/2013 11:39:24 AM---Arif, In xcat dns, the dns server is set up on the management node, while the From: Jing CDL Sun <[email protected]> To: xCAT Users Mailing list <[email protected]>, Cc: xCAT Users Mailing list <[email protected]> Date: 10/25/2013 11:39 AM Subject: Re: [xcat-user] makedns issue Arif, In xcat dns, the dns server is set up on the management node, while the service node only acts as a dns forwarder, that means if a new host needs to be resolved, then the service node will forward this dns request to the management node, so if the management node goes down, that will not work. BTW, I have fixed bug #3853, the fix will be included in xcat 2.8.3 release. Arif Ali <[email protected]> 2013/10/25 16:57 Please respond to xCAT Users Mailing list <[email protected]> To xCAT Users Mailing list <[email protected]>, cc Subject Re: [xcat-user] makedns issue Jing, The purpose of having multiple entries including SN in networks.nameservers is so that if the MN goes down, then we still have a SN to be able to get DNS and host resolution. I hope that makes sense. Would it make sense to allow this? regards, Arif -- Arif Ali IRC: arif-ali at freenode LinkedIn: http://uk.linkedin.com/in/arifali On 24 October 2013 04:24, Jing CDL Sun <[email protected]> wrote: [root@defiant ~]# tabdump -d networks|grep xcatmaster gateway: The network gateway. It can be set to an ip address or the keyword <xcatmaster>, the keyword <xcatmaster> indicates the cluster-facing ip address configured on this management node or service node. Leaving this field blank means that there is no gateway for this network. nameservers: A comma delimited list of DNS servers that each node in this network should use. This value will end up in the nameserver settings of the /etc/resolv.conf on each node in this network. If this attribute value is set to the IP address of an xCAT node, make sure DNS is running on it. In a hierarchical cluster, you can also set this attribute to "<xcatmaster>" to mean the DNS server for each node in this network should be the node that is managing it (either its service node or the management node). Used in creating the DHCP network definition, and DNS configuration. [root@defiant ~]# Both networks.gateway and networks.nameservers are supported. https://sourceforge.net/p/xcat/bugs/3853/ was opened to tace the issue - #3853 makedns ignores the hosts within the net where networks.nameservers is a comma delimited list Arif Ali <[email protected]> 2013/10/23 22:21 Please respond to xCAT Users Mailing list <[email protected]> To xCAT Users Mailing list <[email protected]>, cc Subject Re: [xcat-user] makedns issue Thanks for that, When the <xcatmaster> started to get supported for the gateway option, I tried this option on other parameters in the networks table, but that was unsupported. Could you clarify, which columns are supported, and which are not. As I tried this under tftpserver, and that didn't quite go as planned. regards, Arif -- Arif Ali IRC: arif-ali at freenode LinkedIn: http://uk.linkedin.com/in/arifali On 22 October 2013 09:20, Jing CDL Sun <[email protected]> wrote: Forgot to mention, you could refer to https://sourceforge.net/apps/mediawiki/xcat/index.php?title=Cluster_Name_Resolution for the detailed usage of makedns, this doc includes several typical scenarios and configuration examples. Thx. Jing CDL Sun/China/IBM@IBMCN 2013/10/22 09:51 Please respond to xCAT Users Mailing list <[email protected]> To xCAT Users Mailing list <[email protected]>, cc xCAT-user <[email protected]> Subject Re: [xcat-user] makedns issue Hi Arif, Here is the code I added for your reqirement a few months ago: unless (($_->{nameservers} eq $myip) || ($_->{nameservers} eq '<xcatmaster>') || ($_->{nameservers} eq $sitens)) so in this check, if the networks.nameservers is not mn's IP facing networks.net, or <xcatmaster>, or site.nameservers, then we exclude this net from dns zones. Back to your case, I did not quite understand why "the networks.nameservers is populated as the MN,SN1,SN2", could you explain more? Thx. because in the hierarchical cluster, we recommend the user to set site.nameservers or networks.nameservers to <xcatmaster>, then the "<xcatmaster>" keyword will be interpreted as the value of the "xcatmaster" attribute of the node definition. The "xcatmaster" value for a node is the name of it's server as known by the node. This would be either the cluster-facing name of the service node or the cluster-facing name of the management node. So I'm thinking it should be enough to point the compute node's nameserver either to mn or sn, but not both...Please correct me if I'm worng... On the other hand, I think your report should be a valid bug from the code logic's point of view, because I should have considered the multiple nameservers case in the code, my fault... we need to split the networks.nameservers first instead of using it directly, I will fix this part. Thx. Jing Arif Ali <[email protected]> 2013/10/22 00:18 Please respond to xCAT Users Mailing list <[email protected]> To xCAT-user <[email protected]>, cc Subject [xcat-user] makedns issue Hi devs, a few months ago I put in a request wrt makedns to not create any external based domain name records in named.conf, and therefore to be ignored. This was implemented in a way such that if the networks.nameservers is populated, that network would be disabled. The issue that I have now at a customer site is that the networks.nameservers is populated as the MN,SN1,SN2, i.e. the Management node and the 2 service nodes. For this specific scenario, the hosts within the network is being ignored, i.e. Ignoring host node001, it does not belong to any nets defined in networks table or the net it belongs to is configured to use an external nameserver. Is this the design, or could we have a look into this such that if the ip address specified in the networks.nameservers is MN/SN, then these entries are ignored for makedns? The customer upgraded from 2.8.1 to 2.8.2 recently, and then reverted back to get back the relevant DNS in named back I hope that makes sense. -- Arif Ali IRC: arif-ali at freenode LinkedIn: http://uk.linkedin.com/in/arifali ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60135031&iu=/4140/ostg.clktrk _______________________________________________ xCAT-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/xcat-user ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. 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