/ Eucalyptus DNS HA

Eucalyptus 3 DNS HA configuration tips

Eucalyptus 3.0 GA release brings HA features, but it does not use Virtual IP to provide an unique access point to CLC and Walrus service, it uses DNS delegation to privide an unique domain name to map primary CLC and Walrus IPs.

CLC domain name: eucaluptus.euca-subdomain.yourdomain, e.g. eucalyptus.kimi3.cd.nsn-rdnet.net, this name is mapped to primary CLC IP.
Walrus domain name: walrus.euca-subdomain.yourdomain, e.g. walrus.kimi3.cd.nsn-rdnet.net, this name is mapped to primary Walrus IP.

To achieve this DNS HA, we need to configure properly on both CLCs and external DNS server.

  1. Configure on primary CLC and secondary CLC
    a. On both CLC, make sure to setup your hostname with your whole domain name in /etc/sysconfig/network.
    This takes effect after reboot, you can also use “hostname” command to set it into use immediately.

[[email protected] ~]# cat /etc/sysconfig/network NETWORKING=yes HOSTNAME=Euca3-FE-1.kimi3.cd.nsn-rdnet.net

[[email protected] ~]# cat /etc/sysconfig/network NETWORKING=yes HOSTNAME=Euca3-FE-2.kimi3.cd.nsn-rdnet.net

b. Configure subdomain, enable IP mapping and DNS delegation on primary CLC

[[email protected] ~]# euca-modify-property system.dns.dnsdomain=kimi3.cd.nsn-rdnet.net [[email protected] ~]# euca-modify-property -p bootstrap.webservices.use_instance_dns=true [[email protected] ~]# euca-modify-property -p bootstrap.webservices.use_dns_delegation=true

  1. Configure on external DNS server

  2. Open /etc/named.conf to check yourdomain name zone file

zone “cd.nsn-rdnet.net” IN { type master; file “named.cdrdnet”; allow-transfer {;}; allow-update {none;}; };

zone “kimi3.cd.nsn-rdnet.net” { type forward; forward only; forwarders {;; }; };

b. Edit named.cdrdnet zone file, to add follwoing entries:
Note: the name server names after “NS” must be the same as hostnames we configured above on primary and secondary CLC hosts.

kimi3.cd.nsn-rdnet.net. IN NS Euca3-FE-1.kimi3.cd.nsn-rdnet.net. kimi3.cd.nsn-rdnet.net. IN NS Euca3-FE-2.kimi3.cd.nsn-rdnet.net. Euca3-FE-1.kimi3.cd.nsn-rdnet.net. IN A Euca3-FE-2.kimi3.cd.nsn-rdnet.net. IN A