Setting up stand by LAN interface for primary LAN in cluster

[Abid Iqbal]

Three node cluster running SGeRAC
Sample node1 configuration in cmclconf file is

NODE_NAME node1
NETWORK_INTERFACE lan0
HEARTBEAT_IP 10.10.10.22
NETWORK_INTERFACE lan3
HEARTBEAT_IP 1.1.1.11
NETWORK_INTERFACE lan4
STATIONARY_IP 2.2.2.22
NETWORK_INTERFACE lan1
NETWORK_INTERFACE lan2
NETWORK_INTERFACE lan5

Three stand by LAN interfaces.
Is it possible that LAN0 stand by interface be only LAN1?
If LAN0 fails, its IP should be assigned to LAN1 and if LAN1 fails then no other/next available stand by LAN should be assigned that IP.

[Manix]

It depends upon physical cabling as well..

When you execute cmquerycl/cmcheckconf/cmapplyconf, ServiceGuard will test connectivity between all LAN interfaces included in the configuration. It will pick each interface in each node and try to reach all other interfaces through that. With the results of this operation, ServiceGuard automatically detects what your standby interfaces are good for and selects an appropriate use for each of them.

http://h30499.www3.hp.com/t5/Serviceguard/SG-cluster-congiguration-with-2-standby-LAN/m-p/4452771#M16829

[Stephen Doud]

When cmquerycl is used to create a cluster ASCII configuration file, it also appends comments in the resulting file that describe potential standby LAN information to each node section in the resulting ASCII file.

Example comments loaded with cmquerycl:
# Primary Network Interfaces on Bridged Net 1: lan2.
# Possible standby Network Interfaces on Bridged Net 1: lan3,lan1.

These messages will alert you to whether there are none, one or more than one NIC that can act as a potential standby LAN for a given primary lan.

Please check the content of the output of the cmquerycl command that you use to generate the ASCII configuration file and see what Serviceguard discovered. If it does not suit you, you may have to bridge the network between NICs that have an IP and those that do not, to insure a standby NIC is available.

[Abid Iqbal]

Below is the said output form ascii file

# Possible standby Network Interfaces for lan0,lan3: lan1,lan2,lan5
These interfaces are physically connected to a switch and configured in different VLANs.

[Manix]

>>># Possible standby Network Interfaces for lan0,lan3: lan1,lan2,lan5
These interfaces are physically connected to a switch and configured in different VLANs.

so this is as per the network configurations
& it says for lan0 & 3 ( that is heartbeat
interfaces only) standbys are lan1,lan2,lan5
as we may see the same thing matching with cluster.conf file

There are no standbys for "stationary Ip"

ODE_NAME node1
NETWORK_INTERFACE lan0
HEARTBEAT_IP 10.10.10.22
NETWORK_INTERFACE lan3
HEARTBEAT_IP 1.1.1.11
NETWORK_INTERFACE lan4
STATIONARY_IP 2.2.2.22
NETWORK_INTERFACE lan1
NETWORK_INTERFACE lan2
NETWORK_INTERFACE lan5

For the other requirements we need to change
the network settings.

Hello Stephen ,Please have a look -))

[Stephen Doud]

So Abid's original question was:
Is it possible that LAN0 stand by interface be only LAN1?
If LAN0 fails, its IP should be assigned to LAN1 and if LAN1 fails then no other/next available stand by LAN should be assigned that IP.

After checking the cluster ASCII file that was created by cmquerycl, you learned that:
# Possible standby Network Interfaces for lan0,lan3: lan1,lan2,lan5
These interfaces are physically connected to a switch and configured in different VLANs.

The comment indicates there are 3 potential standby interfaces (lan1, lan2 and lan5) for both lan0 and lan3. This answers Abid's original question.

Manix stated:
There are no standbys for "stationary Ip" (lan4).
For the other requirements we need to change
the network settings.

Though every active NIC (those assigned IPs) would benefit from having access to a standby LAN, eventually it is the customer that must decide what level of availability they can afford.

[Abid Iqbal]

Thank you all experts.
The concept is now very clear.