Introduction: Oracle Flex ASM and Flex cluster has been Introduced from oracle 12c Grid infrastructure and this is one the major significant change. To Install and configure the "Flex cluster" it is mandatory to have a GNS VIP configured with DHCP Server for delegation of virtual IP and SCAN IP addresses of all cluster nodes. In normal standard cluster configuration we have to assign node specific virtual IP's in respective cluster nodes "/etc/hosts" file and SCAN IP addresses will be configured in DNS Server and these SCAN IP addresses will be resolved by cluster nodes DNS client service. In GNS configuration things work little different. it's not required to configure the virtual IP's in each cluster node "/etc/hosts" file and even we should not configure the SCAN IP's in DNS domain forward lookup zone. The only configuration that need to be added in DNS forward lookup zone is to have a GNS VIP. The service for GNS is to have a DHCP Server configured and that DHCP Server will have a reserved IP lease. The VIP 's and SCAN IP's will be allocated to all cluster nodes using DHCP Server with GNS VIP. This article illustrates how we can configure a 12c Flex Cluster and Flex ASM on Oracle enterprise Linux using Windows2008R2 as a DNS/DHCP server for GNS sub domain delegation. In this article we are not going to see the detailed Grid Infrastructure pre-requisites configuration. The main goal of this article is to explain the working of GNS using Windows DNS/DHCP Server for Oracle 12c Flex Cluster Installation. In this demonstration we will be using total 6 nodes for Flex cluster deployment with and its classified as below: S.No Node Name IP Address SW Version Node Description 1 DANODE1 192.168.2.1 2008 DNS/DHCP Server for Node 2 flexrac1 Public Private 12.1.0.1 Cluster Hub-Node 192.168.2.81 10.10.2.81 3 flexrac2 192.168.2.82 10.10.2.82 12.1.0.1 Cluster Hub-Node 4 flexrac3 192.168.2.83 10.10.2.83 12.1.0.1 Cluster Hub-Node 5 flexrac4 192.168.2.84 10.10.2.84 12.1.0.1 Cluster Leaf-Node 6 flexrac5 192.168.2.85 10.10.2.85 12.1.0.1 Cluster Leaf-Node Deployment topology diagram: High Level steps for deployment: Configure the DNS Server Add GNS VIP and cluster nodes to domain service Create a new sub domain delegation Configure DHCP Server Configure /etc/hosts file Configure oracleasm library Flex Cluster Installation verify cluster 1- Configure the DNS Server: The DNS Server will be responsible for resolving the Incoming client connections. Clients will connect to database using SCAN IPs and these SCAN IP's will be generated from windows DHCP server and it will be resolved by configured DNS sub domain delegation. If DNS Server is already configure then we can jump to second step. - "dcpromo" is the command used for configuring the DNS Server in widows environment - Follow the screens for Active Directory Domain Service Installation - select on "Create a new domain in a new forest". If already domain exists then we can select Existing forest. - Here we should provide the fully qualified name for the domain. This will be root domain and all name resolution for public/VIP/Scan-IP/GNS-VIP will be resolved using this domain name - This will setup the domain functional level. This will only allow to add domain controllers from windows2008 and later. The domain server configuration completed successfully. 2- Add GNS VIP and cluster nodes to domain service: In standard cluster all public IP's, Virtual IP's and SCAN-Ip's should be registered in DNS server forward lookup zone. In flex cluster only public IP and GNS Vip should be added to DNS Server forward lookup zone. - This is the GNS VIP and this IP should be resolved by nslookup command on all cluster nodes. - Similarly we should add all cluster public IP's in domain. Here in this demonstration domain name is "dbamaze.com" 3- Create a new DNS sub domain delegation: Navigate to DNS Manager >> Forward Lookup zones >> domain name then right click here to create a new DNS sub domain delegation - Here it is mandatory to select the name configured earlier for GNS VIP. In this demonstration "flexrac" is the virtual host name of GNS VIP. Click on "Resolve" and it should resolve the provided IP address and FQDN The Sub domain creation completed. Now we can see the sub domain "flexrac1" under root domain "dbamaze.com" - Verify cluster nodes are able to communicate with DNS Server [root@flexnode1 ~]# ping danode1.dbamaze.com PING danode1.dbamaze.com (192.168.2.10) 56(84) bytes of data. 64 bytes from 192.168.2.10: icmp_seq=1 ttl=128 time=0.453 ms 64 bytes from 192.168.2.10: icmp_seq=2 ttl=128 time=0.553 ms 64 bytes from 192.168.2.10: icmp_seq=3 ttl=128 time=0.506 ms 64 bytes from 192.168.2.10: icmp_seq=4 ttl=128 time=0.924 ms - Verify name resolution of GNS Name "flexrac" and its VIP - Perform this step on all cluster nodes to verify connectivity. 4 -Configure DHCP Server: The configuration of DNS root domain and GNS Sub domain has been completed. The next step is to configure the DHCP Server using GNS Sub domain delegation. This DHCP server will assign the Cluster nodes virtual IP's and SCAN IP's. Navigate to Windows Start >> Administrative tools >> Server Manager - Click on "add roles" - From the server roles Menu select " DHCP Server " - By default it will select the root domain IP address. - Here provide the parent domain name " danode1.dbamaze.com " and provide the GNS VIP address. - Specify the range of IP addresses that should be reserved in the DHCP lease. This range should be reserved based on the number of cluster nodes . - select " Disable DHCPV6 " - provide the admin password - DHCP Server Installation summary. - DHCP server Address pool The Installation and configuration of DHCP Server completed successfully. Now we are ready to proceed with the Installation of Flex cluster. 5 - Configure "/etc/hosts" file: "/etc/hosts" file doesn't contains the entries with virtual IP addresses. All virtual IP addresses Including SCAN IP's will be managed by GNS virtual hostname. Private IP address should be configured on all cluster nodes if using "ASM & Private" Network option and If not using this option then Private IP address can be configured only on Hub Nodes and it's not required to be used on leaf nodes. Sample "/etc/hosts" file from flexnode1: [root@flexnode1 bin]# cat /etc/hosts # Do not remove the following line, or various programs # that require network functionality will fail. 127.0.0.1 localhost.localdomain localhost ############PUBLIC############################## 192.168.2.81 flexnode1.dbamaze.com flexnode1 localhost 192.168.2.82 flexnode2.dbamaze.com flexnode2 192.168.2.83 flexnode3.dbamaze.com flexnode3 192.168.2.84 flexnode4.dbamaze.com flexnode4 192.168.2.85 flexnode5.dbamaze.com flexnode5 ###############PRIVATE########################## 10.10.2.81 flexnode1-priv.dbamaze.com flexnode1-priv 10.10.2.82 flexnode2-priv.dbamaze.com flexnode2-priv 10.10.2.83 flexnode3-priv.dbamaze.com flexnode3-priv 10.10.2.84 flexnode4-priv.dbamaze.com flexnode4-priv 10.10.2.85 flexnode5-priv.dbamaze.com flexnode5-priv #################VIP########################### ##NO NEED FOR VIP AS ITS A GNS INSTALLATION##### [root@flexnode1 bin]# 6 - Configure oracleasm library We have to ensure that all required ASM rpm packages are installed on all participating cluster nodes. In a Flex Cluster configuration ASM shared storage disks should be configured only on Hub nodes and it is not required to configure the ASM shared storage disks on Leaf nodes. [root@flexnode1 ~]# oracleasm listdisks <<---- HUB Node DISK1 DISK2 DISK3 [root@flexnode2 bin]# oracleasm listdisks <<---- HUB Node DISK1 DISK2 DISK3 [root@flexnode3 bin]# oracleasm listdisks <<---- HUB Node DISK1 DISK2 DISK3 [root@flexnode4 ~]# oracleasm listdisks <<---- Leaf Node [root@flexnode4 ~]# [root@flexnode5 ~]# oracleasm listdisks <<----Leaf Node [root@flexnode5 ~]# Conclusion This part of article covers configuration of DNS/DHCP Server on windows for GNS Sub domain delegation. We have to make sure the IP addresses configured in the DHCP lease has not been used by any other server. If any of the IP is used in network then "root.sh" script will fail. GNS sub domain will allocate Virtual IP's in consecutive fashion. Once the configuration of DNS/DHCP Server is completed we are ready to begin Installation of 12c Flex cluster. In next part of this article we will see the Installation of Flex cluster.
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