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Customizing the private IP address range with the Flexible IP Addressing Scheme

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What is the cluster private IP address range and how is it used?

Sun Cluster inter-node communication happens over the redundant private networks and these require a range of private IP addresses primarily for the following two purposes:

  • Per-node IP addresses: These are used by applications for inter-node communication over the private interconnect.
  • Per-adapter IP addresses: These addresses are used by the cluster interconnects for inter-node infrastructure traffic.

For these purposes, Sun Cluster reserves a 16-bit IP address range and allots IP addresses from this range.

What is this new feature?

Flexible IP Addressing Scheme, new feature available in Sun Cluster 3.2, eliminates the 16-bit address requirement for the cluster interconnect and makes the IP address range smaller and more flexible.

Highlights:

  • Provides an option to customize the private IP address range for an individual cluster setup.
  • Eliminates the 16-bit requirement for the private network addresses.
  • Provides an interface to modify the IP address range assigned to the cluster after installation.

Why do I need this?

  • Reduces the "wastage" of IP addresses:
    The default 16-bit IP address range yields to 64K addresses which are all reserved even when the current cluster setup might actually use just a few addresses from this reserved space. By using the new feature, the address range can be configured with minimal required IP addresses.
  • Provides flexibility: This project provides a facility to modify the IP address range. This can be useful when physically moving a cluster from one location to another, or switching the cluster from test mode to production mode, or when resizing the current cluster.
  • Cost effective: In some cases, customers might be getting charged for the IP addresses they use. With the new scheme, customers can allocate just the required number of IP addresses and thereby eliminate the costs associated with the extra IP addresses reserved by cluster.

How do I use this?

This feature provides options for setting the private IP address range during cluster installation, and modifying it later.

Scinstall, either interactive or command line version, can be used to customize the IP address range during the install, and clsetup menu or cluster command can be used in non-cluster mode to change the IP address range at later time.

Figures 1-4 demonstrate the scinstall options to customize the IP address range and Figures 5-6 show the usage of clsetup and cluster command to change the existing IP address range. For changing the existing IP address range with clsetup or cluster command, all the cluster nodes need to be in non-cluster mode.

Figure 1: Using the default Values : scinstall provides the default values which can accommodate 64-nodes and 10 private networks:

>>> Network Address for the Cluster Transport <<<

The private cluster transport uses a default base IP address of
172.16.0.0. If this IP address is already in use elsewhere
within your enterprise, specify another address from
the range of recommended private addresses (see RFC 1918 for details).

The default netmask is 255.255.248.0. You can select another netmask as
long as it minimally masks all bits in the base IP address.

The default base IP address and default netmask yield an IP address
range that supports a cluster with a maximum of 64 nodes and a
maximum of 10 private networks.

Is it okay to accept the default base IP address (yes/no) [yes]? yes
Is it okay to accept the default netmask (yes/no) [yes]? yes

The base IP address and netmask that you specified yields an IP address
range that supports a cluster with a maximum of 64 nodes and a maximum
of 10 private networks.

Would you like to use this range and proceed with the installation (yes/no) [yes]? yes

Figure 2: Customizing only the network address

Is it okay to accept the default base IP address (yes/no) [yes]? No
What base IP address do you want to use [172.16.0.0]? 172.18.0.0

Is it okay to accept the default netmask (yes/no) [yes]? yes

The base IP address and netmask that you have specified yields an IP
address range that supports a cluster with a maximum of 64 nodes and a
maximum of 10 private networks.

Would you like to use this range and proceed with the installation (yes/no) [yes]? yes

Figure 3: Customizing the network address and netmask

Is it okay to accept the default base IP address (yes/no) [yes]? yes

Is it okay to accept the default netmask (yes/no) [yes]? No
What is the maximum number of nodes that you expect to configure in this cluster? 4
What is the maximum number of private networks that you expect to configure in this cluster? 2

A netmask of (X) is the minimum required to support 4 nodes and 2 private networks
in the cluster.

A netmask of (Y) would support 8 nodes and 4 private networks in the cluster, to accommodate future expansion of the cluster.

What netmask would you like to use [(Y)]? (X)
The base IP address and netmask that you specified yields an IP address
range that support s a cluster with a maximum of 4 nodes and a maximum
of 2 private networks.

Would you like to use this range and proceed with the installation (yes/no) [yes]? yes

Figure 4: scinstall command line syntax for changing the network address and netmask with two new options:

scinstall -w netaddr=netaddr[,maxnodes=nodes,maxprivnets=privnets]

scinstall  -w netaddr=netaddr[,netmask=netmask,maxnodes=nodes,maxprivnets=privnets]

Here, netaddr indicates the base IP address, netmask is the desired netmask, maxnodes indicates the maximum number of nodes expected to be in the cluster, and maxprivnets indicates the maximum number of private networks expected to be in the cluster.

Figure 5: clsetup menu in non-cluster mode to modify the current IP address range
poctet1# clsetup

    \*\*\* Main Menu \*\*\*

    Select from one of the following options:

        1) Change Network Addressing and Ranges for the Cluster Transport
        2) Show Network Addressing and Ranges for the Cluster Transport

        ?) Help with menu options
        q) Quit

    Option:  1

 >>> Change Network Addressing and Ranges for the Cluster Transport <<<

    Network addressing for the cluster transport is currently configured
    as follows:

    ...
    Private network address:    172.16.0.0
    Private netmask:            255.255.255.192
    Maximum nodes:              6
    Maximum private networks:   4

    Do you want to change this configuration (yes/no) [yes]?
    The default network address for the cluster transport is 172.16.0.0.

    Do you want to use the default (yes/no) [yes]?

    The default netmask for the cluster transport is 255.255.248.0.

    Do you want to use the default (yes/no) [yes]?  no

    ...

    Maximum number of nodes anticipated for future growth [64]?  16

    Maximum number of private networks anticipated for future growth [10]?  4

    Specify a netmask of 255.255.255.0 to meet anticipated future
    requirements of 16 cluster nodes and 4 private networks.

    To accommodate more growth, specify a netmask of 255.255.252.0 to
    support up to 32 cluster nodes and 8 private networks.

    What netmask do you want to use [255.255.255.0]?
    Is it okay to proceed with the update (yes/no) [yes]?

cluster set-netprops -p private_netaddr=172.16.0.0 -p private_netmask=255.255.255.0 -p max_nodes=16 -p max_privatenets=4
...
Command completed successfully.

Figure 6: Modifying the IP address range with "cluster" command in non-cluster mode

cluster set-netprops -p private_netaddr=<netaddr> -p max_nodes=<nodes> -p max_privatenets=<private_nets>

or

cluster set-netprops -p private_netaddr=<netaddr> -p private_netmask=<netmask>

Where do I get info about this?

Sun Cluster System Administration Guide
http://docs.sun.com/app/docs/doc/819-2971/6n57mi2bq?a=view

Thanks,
Prasanna Kunisetty
Sun Cluster Engineering

Join the discussion

Comments ( 3 )
  • guest Tuesday, April 24, 2007
    There was a question posted to find out how to use the cluster set-netprops command to modify the existing private IP address range. Following is the response:
    In order to modify the existing IP address range using the cluster command, the cluster should be in non-cluster mode. For example, on my node (which is non-cluster mode):
    1) Run the following to see the current info:
    # cluster show-netprops
    === Private Network ===
    private_netaddr: 172.16.0.0 private_netmask: 255.255.248.0
    max_nodes: 64
    max_privatenets: 10
    2) You can change any of the above values using the cluster command. Here, as an example I chose to modify the private_netaddress:
    # cluster set-netprops -p private_netaddr=172.12.0.0
    That's it. Running the above command from one of the nodes will take care of it. You can see the new values again with cluster command:
    # cluster show-netprops
    === Private Network ===
    private_netaddr: 172.12.0.0
    private_netmask: 255.255.248.0
    max_nodes: 64
    max_privatenets: 10
    3) Now boot the cluster back into cluster mode and the new IP address range is active now.
    Note: Alternatively, clsetup interactive menu can also be used to modify the IP address range.
    Thanks,
    Prasanna Kunisetty
  • Ardy Thursday, January 8, 2009

    may you help me ??

    please e-mail me....

    i have a question to ask you...

    in IP address, there's 8 bit IP address, 16 bit, and 32 bit....

    if you can help me to answer it, please e-mail me...


  • Ardy Thursday, January 8, 2009

    here's my e-mail, ch3ater_4ever@yahoo.com


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