Renaming the Nodes and Setting up the Network Oracle Database Tips by Donald Burleson

With the desktop images changed, it is easy to determine which node is on the screen at any time, but only when using the graphical interface gnome. The command line logins that can be accessed by typing [CTL+ALT+F1] through [CTL+ALT+F6] still appear the same on each node. To configure each node so that those logins include the node name instead of ?localhost,? the hostname and network settings must be configured.

Each node has two Network Interface Cards (NICs) identified by eth0and eth1. With Fedora installed on the computers used for writing this book, eth0 was the NIC closest to the ceiling, and eth1 was the NIC closest to the floor. However, your computer hardware may produce different results.

To assign an IP that will work for the public network (eth1), you must find the IP address of your router. Both a Microsoft Router and a Belkin Wireless/Wired Combination Router were tested in writing this book. And in each case, the router was assigned the same IP for the public network by its respective manufacturer: 192.168.2.1. Keep in mind, though, other routers may have a different IP address and thus require different IP addresses on the public network.

To find your router's IP address, try the command ipconfig/all from the DOS prompt of the windows client machine as seen in Figure 2.7. The default gateway reveals the router's IP address.

The important part of the IP address is the first three groups of numbers: 192.168.2.x. It is likely your router supports connected devices from 192.168.2.2 to 192.168.2.255. Usually the first 30 or so addresses are reserved for DHCP, or dynamically assigned IP addresses. DHCP addresses allow for a device to be plugged into the local network. The router automatically detects and leases an IP address to the device. For this project, however, static IP addresses will be used.

Now, you need to determine which of your two network cards on each node is labeled eth1. For the computers used in writing this book, the NIC cards that were closest to the bottom of the case were assigned the label eth1 by Fedora. To be certain you are working with eth1, temporarily unplug the internal cross-over cable from the cards that is believed to be eth0and make sure the other cards are connected to the router.

On Oracle1, open the Network Configuration Utility by clicking the ?Redhat? icon in the bottom left corner of the desktop, then 'system Settings,? then ?Network?. Alternatively, launch this application by entering redhat‑config‑networkin the run application applet window. A program will appear like that shown in Figure 2.9.

If the devices eth0 or eth1are not shown, which is expected if the installer was launched with the noprobe option, click the ?NEW? button to add them in with the appropriate settings as seen in Figure 2.10.

Double-click the eth1 row and a new window appears like that shown in Figure 2.11. In this dialog, check the box that activates the device when the computer starts. Change the IP to be set statically and type in the appropriate values, thus making the appropriate changes according to what is now known about your router. Click ?OK? and then activate the device. If asked, ?Do you wish to save changes made?? then click ?yes? to continue. 

With eth1 active, its connectivity must be tested by pinging the router. To do this, click the ?Redhat? icon and run the application. In the window that pops up, type in gnome-terminal. From this terminal, ping the router as shown in Figure 2.12; to stop the pinging, type [control+c]. If the pings are not returned by the router, ensure that the cable to the public network is attached properly to both the NIC cardand the router. If that does not work, switch the cable to the alternate NIC card to see if you actually configured that NIC instead.

At this point, you have one NIC cardworking on Oracle1and have identified which NIC is eth1. Now, by repeating the preceding procedure, configure Oracle2 so that its eth1 NIC is able to ping the router as well.

With the NIC cards on the public network configured, fill in the information for your network into the table in Figure 2.8. You are now ready to configure the remaining NICs.

Next, reconnect the crossover cable. Configure and activate the eth0 network card for each node using the same method used for eth1. With the private network configured, you should be able to ping the alternate node's private IP address.

Click the ?Hosts? tab of the Network Configuration Utility. Click ?New,? and type in the address and hostname one at a time for six hosts as shown in Figure 2.13. The order is of the hosts is irrelevant. Use the IP addresses used for eth0and eth. vip-oracle1 and vip‑oracle2 are used by the listeners to support fail-over in an Oracle 10g RAC. Use the prefix for your public network for the two VIP host names. Complete this step on both nodes.

Click the ?DNS? tab on the Network Configuration Utilityto change the hostname for each node to oracle1 and oracle2 respectively.  Type in a primary DNS, which is the IP address for your router. Make absolutely certain that the spelling of the hostname is the same as what was typed in for hosts in the previous step; otherwise, Fedora will become confused on the next reboot.

Once these steps are complete, click the ?File? tab and SAVE. At this point, each node will become unstable. Fedora has a panic attack whenever the hostname is changed. To fix this problem, reboot each node now. Click the ?Redhat? icon and then click the ?logout? icon. This will bring up a dialog in which the computer can be restarted.

After rebooting each node, login and check that you can successfully ping the router, oracle1, oracle2, int-oracle1, and int-oracle2. If not, check that the entries for the hosts are correct as shown in Figure 2.13. Finally, check that the web pages are accessible. If not, it may be that the node is attempting to resolve public addresses on the private network.

Figure 2.15 demonstrates this by using the traceroutecommand to attempt to connect to www.oracle.com. Although the correct IP is found, the int-oracle1 connection is the first attempted hop. This will never work! If this happens, open the redhat‑config‑networkprogram. Remove the default gateway address for the network card on the internal network, and ensure the default gateway is the router's IP address for the card on the public network. Save the configuration and restart the network service with the command /sbin/service network restart.

When the network is completely configured, pinging the private node names, the public node names, and downloading web pages should all work. Once this is successfully configured, make a note in Figure 2.8 to remember which NIC (eth0 or eth1) is on the public network and which is on the private network. The nodes must be configured to use the same NICs (eth1 or eth2) for each network.

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