When installing Oracle Grid Infrastructure 12c, which three options exist for the configuration of Grid naming Service (GNS)?
A.
using Shared GNS for the leaf nodes and local GNS for the hub nodes in a Flex Cluster
B.
using Shared GNS running on another cluster
C.
using Shared GNS for the hub nodes and local GNS for the leaf nodes in a Flex Cluster
D.
creation of a new GNS for this cluster
E.
using DHCP to assign Node Virtual IP addresses for nodes in the cluster
Explanation:
B: With dynamic configurations, you can configure GNS to provide name resolution for one cluster, or to advertise resolution for multiple clusters, so that a single
GNS instance can perform name resolution for multiple registered clusters. This option is called shared GNS.
D: With static configurations, no subdomain is delegated. A DNS administrator configures the GNS VIP to resolve to a name and address configured on the DNS,
and a DNS administrator configures a SCAN name to resolve to three static addresses for the cluster.
E: With automatic configurations, a DNS administrator delegates a domain on the DNS to be resolved through the GNS subdomain. Automatic configuration occurs
in one of the following ways:
For IPv4 addresses, Oracle Clusterware assigns unique identifiers for each cluster member node interface allocated for Oracle Grid Infrastructure, and
generates names using these identifiers within the subdomain delegated to GNS. A DHCP server assigns addresses to these interfaces, and GNS maintains
address and name associations with the IPv4 addresses leased from the IPv4 DHCP pool.
For IPv6 addresses, Oracle Clusterware automatically generates addresses with autoconfig.
https://docs.oracle.com/database/121/CWADD/admin.htm#CWADD838
If you choose to configure Shared GNS, you will be required to provide GNS client data exported from another host serviced by the existing GNS. The configuration process for a client cluster involves registering the client cluster with the GNS server. To perform the registration, a set of GNS server credentials is required. The overall procedure for configuring a GNS client cluster is as follows:
1. Export the GNS credentials on the server cluster by using the srvctl export gns
command and specifying a file to store the GNS credentials.
2. Copy the credentials file to the client cluster by using a network file copy (ftp or scp,for example) or a physical file transfer (CD, DVD, or memory stick, for example).
3. On the Oracle Universal Installer “Grid Plug and Play Information” screen, select “Use Shared GNS” and specify the credentials file in the GNS Client Data field. Click Next to continue.
B,D,E correct
“B”, “D” and “E”!
“https://docs.oracle.com/database/121/CWADD/admin.htm#CWADD92596
Clusterware Administration and Deployment Guide
Shared GNS Option for Addresses
With dynamic configurations, you can configure GNS to provide name resolution for one cluster, or to advertise resolution for multiple clusters, so that a single GNS instance can perform name resolution for multiple registered clusters. This option is called shared GNS.
Shared GNS provides the same services as standard GNS, and appears the same to clients receiving name resolution. The difference is that the GNS daemon running on one cluster is configured to provide name resolution for all clusters in domains that are delegated to GNS for resolution, and GNS can be centrally managed using SRVCTL commands. You can use shared GNS configuration to minimize network administration tasks across the enterprise for Oracle Grid Infrastructure clusters.
You cannot use the static address configuration option for a cluster providing shared GNS to resolve addresses in a multi-cluster environment. Shared GNS requires automatic address configuration, either through addresses assigned by DHCP, or by IPv6 stateless address autoconfiguration.
Oracle Universal Installer enables you to configure static addresses with GNS for shared GNS clients or servers, with GNS used for discovery.”
“Oracle RAC Expert 12c
After you select this Flex Cluster configuration option, as the prerequisite for Flex Cluster installation, you need to specify the GNS configuration in the installation as shown in Figure 4-3: selecting the “Configure GNS” option and specifying the new fixed GNS VIP address, which will be used in the rest the installation steps.
…
Select Whether or Not to Use GNS
If you decide to use GNS for the name resolution, you need to check the box next to “Configure GNS” on the Grid Plug and Play information page. In Oracle 12c, a single GNS can be shared by multiple clusters. When you create a new cluster, you can either share an existing GNS with other cluster by selecting “Use Shared GNS” or “create a new GNS” by selecting the “Create a New GNS” option. On the same page, you also need to fill out the GNS subdomain and the GNS VIP address as shown in Figure 9-11, which uses the knewrac cluster as an example.
If you use the typical standard cluster installation, in which you by default use the DNS, you leave the “Configure GNS” box unchecked. However, if you plan to implement the Oracle Flex Cluster option in Oracle 12cR1, you are required to configure GNS with a fixed VIP on one of the hub nodes. Refer to Chapter 4 for a detailed discussion of the network configuration for Flex Clusters and Flex ASM.”
“https://docs.oracle.com/database/121/CWLIN/networks.htm#CWLIN478
5.10.1 General Requirements for Oracle Flex Cluster Configuration
Note the following requirements for Oracle Flex Cluster configuration:
– You must use Grid Naming Service (GNS) with an Oracle Flex Cluster deployment.
– You must configure the GNS VIP as a static IP address for Hub Nodes.
– On Multi-cluster configurations, you must identify the GNS client data file location for Leaf Nodes. The GNS client data files are copied over from the GNS server before you start configuring a GNS client cluster.
– All public network addresses for both Hub Nodes and Leaf Nodes, whether assigned manually or automatically, must be in the same subnet range.
– All Oracle Flex Cluster addresses must be either static IP addresses, DHCP addresses assigned through DHCP (IPv4) or autoconfiguration addresses assigned through an autoconfiguration service (IPv6), registered in the cluster through GNS.”