Oracle Exalogic Elastic Cloud X2-2 Hardware
 
Oracle Exalogic Elastic Cloud Software
 

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Goal

Solution

References

Created from <SR 3-8795006131>

Applies to:

Goal

Customers are sometimes in need to assign new IP addresses for new projects.  Virtual IPs are usually created in the compute nodes and based on the current default configuration (or what was configured during the set up of the system) new IPs are needed. For that is necessary to modify the "network mask" so new IPs can be created on InfiniBand network.

For example, all IPs of this network from 172.24.16.0 until 172.24.16.255 are busy for several projects, and you need to configure other new IPs but the current network mask is set to 255.255.255.0 and no IPs available for allocation.
 

Solution

This situation can be revised and checked with an IPv4 subnet calculator.

A calculator will allow to enter the IP address to be used along with the mask and calculate the IPs, network, broadcast and number of network IPs that will be available.  Here's a quick sample of a calculator in which the IP address in use is "172.24.16.0" and Network Mask was changed from "255.255.255.0" to "255.255.252.0"

Note that the 3rd octet has changed from "255" to "252".  The new parameters are:

Once the network mask has been determined and parameters collected,  performe the next steps on ALL compute nodes of the Exalogic system:

1. For IPoIB network you don't need to modify the gateway as this is internal to the system.
   
   
2. Next, you need to modify the network script for the IPoIB network (bond0).  This is located in the following directory of the compute node:
   
   /etc/sysconfig/network-script/ifcfg-bond0
   
   
   Note: Before making any modifications make sure the network script files in this directory are backed up.
     
   In this file you will modify the "NETMASK" to the network mask that has been selected. For example:
   
   
   # cat /etc/sysconfig/network-scripts/ifcfg-bond0
   ######## DO NOT EDIT THIS FILE ########
   ######## GENERATED BY EXALOGIC ########
   DEVICE=bond0
   IPADDR=172.24.16.8
   NETMASK=255.255.252.0   <------------------ Network mask change to 255.255.252.0
   BOOTPROTO=none
   USERCTL=no
   TYPE=Ethernet
   ONBOOT=yes
   IPV6INIT=no
   BONDING_OPTS="mode=active-backup miimon=100 downdelay=5000 updelay=5000"
   MTU=65520
    
   
   
3. The file /etc/sysconfig/network should be left alone and not be modified.
   
   
4. The final step is to either restart the network service on the compute node or use "ifdown" "ifup" commands to restart the bond0 interface only.
   
   # service network stop    <------------------- Stop network services
# service network start   <------------------- Start network services

     
   
   # ifdown bond0   <--------------- Bring down interface bond0
   # ifup bond0     <--------------- Bring up interface bond0
     

If virtual IPs have been created on the compute nodes, such as bon0:1 bond0:2 ... bond0:254, you must also change the NETMASK for those virtual IP network scripts.  This is needed for these interfaces to also work and communicate over the same network. Just as the note above, make sure to back up the scripts before making any modifications.

Test with a couple of compute nodes first, see if they can communicate after making the changes.

References

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