Sun Cluster Data Services Planning and Administration Guide for Solaris OS

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Adding or Removing a Node to or From a Resource Group

The procedures in this section enable you to perform the following tasks.

Configure a cluster node to be an additional master of a resource group.
Remove a node from a resource group.

The procedures are slightly different, depending on whether you plan to add or remove the node to or from a failover or scalable resource group.

Failover resource groups contain network resources that both failover and scalable services use. Each IP subnetwork connected to the cluster has its own network resource that is specified and included in a failover resource group. The network resource is either a logical hostname or a shared address resource. Each network resource includes a list of IP Networking Multipathing groups that it uses. For failover resource groups, you must update the complete list of IP Networking Multipathing groups for each network resource that the resource group includes (the netiflist resource property).

For scalable resource groups, in addition to changing the scalable group to be mastered on the new set of hosts, you must repeat the procedure for failover groups that contain the network resources that the scalable resource uses.

See the scrgadm(1M) man page for additional information.

Note –

Run either of these procedures from any cluster node.

Adding a Node to a Resource Group

The procedure to follow to add a node to a resource group depends on whether the resource group is a scalable resource group or a failover resource group. For detailed instructions, see the following sections:

You must supply the following information to complete the procedure.

The names and node IDs of all of the cluster nodes
The names of the resource groups to which you are adding the node
The name of the IP Networking Multipathing group that will host the network resources that are used by the resource group on all of the nodes

Also, be sure to verify that the new node is already a cluster member.

How to Add a Node to a Scalable Resource Group

For each network resource that a scalable resource in the resource group uses, make the resource group where the network resource is located run on the new node.

See Step 1 through Step 4 in the following procedure for details.

Add the new node to the list of nodes that can master the scalable resource group (the nodelist resource group property).

This step overwrites the previous value of nodelist, and therefore you must include all of the nodes that can master the resource group here.
# scrgadm -c -g resource-group -h nodelist
-c

Changes a resource group.

-g resource-group

Specifies the name of the resource group to which the node is being added.

-h nodelist

Specifies a comma-separated list of the names of the nodes that can master the resource group.

(Optional) Update the Load_balancing_weights property of the scalable resource to assign a weight to the node that you want to add to the resource group.

Otherwise, the weight defaults to 1. See the scrgadm(1M) man page for more information.

How to Add a Node to a Failover Resource Group

Display the current node list and the current list of IP Networking Multipathing groups that are configured for each resource in the resource group.
# scrgadm -pvv -g resource-group | grep -i nodelist # scrgadm -pvv -g resource-group | grep -i netiflist
Note –
The output of the command line for nodelist and netiflist identifies the nodes by node name. To identify node IDs, run the command scconf -pv | grep -i node_id.

Update netiflist for the network resources that the node addition affects.

This step overwrites the previous value of netiflist, and therefore you must include all of the IP Networking Multipathing groups here.
# scrgadm -c -j network-resource -x netiflist=netiflist
-c

Changes a network resource.

-j network-resource

Specifies the name of the network resource (logical hostname or shared address) that is being hosted on the netiflist entries.

-x netiflist=netiflist

Specifies a comma-separated list that identifies the IP Networking Multipathing groups that are on each node. Each element in netiflist must be in the form of netif@node. netif can be given as an IP Networking Multipathing group name, such as sc_ipmp0. The node can be identified by the node name or node ID, such as sc_ipmp0@1 or sc_ipmp@phys-schost-1.

Update the node list to include all of the nodes that can now master this resource group.

This step overwrites the previous value of nodelist, and therefore you must include all of the nodes that can master the resource group here.
# scrgadm -c -g resource-group -h nodelist
-c

Changes a resource group.

-g resource-group

Specifies the name of the resource group to which the node is being added.

-h nodelist

Specifies a comma-separated list of the names of the nodes that can master the resource group.

Verify the updated information.

# scrgadm -pvv -g resource-group | grep -i nodelist
# scrgadm -pvv -g resource-group | grep -i netiflist

Example – Adding a Node to a Resource Group

This example shows how to add a node (phys-schost-2) to a resource group (resource-group-1) that contains a logical hostname resource (schost-2).

# scrgadm -pvv -g resource-group-1 | grep -i nodelist
(resource-group-1) Res Group Nodelist:    phys-schost-1 phys-schost-3
# scrgadm -pvv -g resource-group-1 | grep -i netiflist
(resource-group-1:schost-2) Res property name: NetIfList
(resource-group-1:schost-2:NetIfList) Res property class: extension
(resource-group-1:schost-2:NetIfList) List of IP Networking Multipathing  
interfaces on each node
(resource-group-1:schost-2:NetIfList) Res property type: stringarray
(resource-group-1:schost-2:NetIfList) Res property value: sc_ipmp0@1 sc_ipmp0@3
 
(Only nodes 1 and 3 have been assigned IP Networking Multipathing groups. 
You must add a IP Networking Multipathing group
for node 2.)

# scrgadm -c -j schost-2 -x netiflist=sc_ipmp0@1,sc_ipmp0@2,sc_ipmp0@3
# scrgadm -c -g resource-group-1 -h phys-schost-1,phys-schost-2,phys-schost-3
# scrgadm -pvv -g resource-group-1 | grep -i nodelist
(resource-group-1) Res Group Nodelist:     phys-schost-1 phys-schost-2
                                           phys-schost-3
# scrgadm -pvv -g resource-group-1 | grep -i netiflist
(resource-group-1:schost-2:NetIfList) Res property value: sc_ipmp0@1 sc_ipmp0@2
                                                          sc_ipmp0@3

Removing a Node From a Resource Group

The procedure to follow to remove a node from a resource group depends on whether the resource group is a scalable resource group or a failover resource group. For detailed instructions, see the following sections:

For an example, see Example – Removing a Node From a Resource Group.

To complete the procedure, you must supply the following information.

Node names and node IDs of all of the cluster nodes
# scconf -pv | grep “Node ID”
Name(s) of the resource group or groups from which you plan to remove the node
# scrgadm -pv | grep “Res Group Nodelist”
Names of the IP Networking Multipathing groups that will host the network resources that are used by the resource group(s) on all of the nodes
# scrgadm -pvv | grep “NetIfList.*value”

Additionally, be sure to verify that the resource group is not mastered on the node that you will remove. If the resource group is mastered on the node that you will remove, run the scswitch command to switch the resource group offline from that node. The following scswitch command will bring the resource group offline from a given node, provided that new-masters does not contain that node.

# scswitch -z -g resource-group -h new-masters

-g resource-group: Specifies the name of the resource group (mastered on the node that you will remove) that you are switching offline.
-h new-masters: Specifies the node(s) that will now master the resource group.

See the scswitch(1M) man page for additional information.

Caution –

If you plan to remove a node from all of the resource groups, and you use a scalable services configuration, first remove the node from the scalable resource group(s). Then, remove the node from the failover group(s).

How to Remove a Node From a Scalable Resource Group

A scalable service is configured as two resource groups, as follows.

One resource group is a scalable group that contains the scalable service resource.
One resource group is a failover group that contains the shared address resources that the scalable service resource uses.

Additionally, the RG_dependencies property of the scalable resource group is set to configure the scalable group with a dependency on the failover resource group. See Appendix A, Standard Properties for details on this property.

See the Sun Cluster Concepts Guide for Solaris OS document for details about scalable service configuration.

Removing a node from the scalable resource group causes the scalable service to no longer be brought online on that node. To remove a node from the scalable resource group, perform the following steps.

Remove the node from the list of nodes that can master the scalable resource group (the nodelist resource group property).
# scrgadm -c -g scalable-resource-group -h nodelist
-c

Changes a resource group.

-g scalable-resource-group

Specifies the name of the resource group from which the node is being removed.

-h nodelist

Specifies a comma-separated list of the names of the nodes that can master this resource group.

(Optional) Remove the node from the failover resource group that contains the shared address resource.

See How to Remove a Node From a Failover Resource Group That Contains Shared Address Resources for details.

(Optional) Update the Load_balancing_weights property of the scalable resource to remove the weight of the node that you want to remove from the resource group.

See the scrgadm(1M) man page for more information.

How to Remove a Node From a Failover Resource Group

Perform the following steps to remove a node from a failover resource group.

Caution –

If you plan to remove a node from all of the resource groups, and you use a scalable services configuration, first remove the node from the scalable resource group(s). Then, use this procedure to remove the node from the failover group(s).

Note –

If the failover resource group contains shared address resources that scalable services use, see How to Remove a Node From a Failover Resource Group That Contains Shared Address Resources.

Update the node list to include all of the nodes that can now master this resource group.

This step removes the node and overwrites the previous value of the node list. Be sure to include all of the nodes that can master the resource group here.
# scrgadm -c -g failover-resource-group -h nodelist
-c

Changes a resource group.

-g failover-resource-group

Specifies the name of the resource group from which the node is being removed.

-h nodelist

Specifies a comma-separated list of the names of the nodes that can master this resource group.

Display the current list of IP Networking Multipathing groups that are configured for each resource in the resource group.
# scrgadm -pvv -g failover-resource-group | grep -i netiflist

Update netiflist for network resources that the removal of the node affects.

This step overwrites the previous value of netiflist. Be sure to include all of the IP Networking Multipathing groups here.
# scrgadm -c -j network-resource -x netiflist=netiflist
Note –
The output of the preceding command line identifies the nodes by node name. Run the command line scconf -pv | grep “Node ID” to find the node ID.

-c

Changes a network resource.

-j network-resource

Specifies the name of the network resource that is hosted on the netiflist entries.

-x netiflist=netiflist

Specifies a comma-separated list that identifies the IP Networking Multipathing groups that are on each node. Each element in netiflist must be in the form of netif@node. netif can be given as an IP Networking Multipathing group name, such as sc_ipmp0. The node can be identified by the node name or node ID, such as sc_ipmp0@1 or sc_ipmp@phys-schost-1.

Note –
Sun Cluster does not currently support using the adapter name for netif.

Verify the updated information.

# scrgadm -pvv -g failover-resource-group | grep -i nodelist
# scrgadm -pvv -g failover-resource-group | grep -i netiflist

How to Remove a Node From a Failover Resource Group That Contains Shared Address Resources

In a failover resource group that contains shared address resources that scalable services use, a node can appear in the following locations.

the node list of the failover resource group
the auxnodelist of the shared address resource

To remove the node from the node list of the failover resource group, follow the procedure How to Remove a Node From a Failover Resource Group.

To modify the auxnodelist of the shared address resource, you must remove and recreate the shared address resource.

If you remove the node from the failover group's node list, you can continue to use the shared address resource on that node to provide scalable services. To do so, you must add the node to the auxnodelist of the shared address resource. To add the node to the auxnodelist, perform the following steps.

Note –

You can also use the following procedure to remove the node from the auxnodelist of the shared address resource. To remove the node from the auxnodelist, you must delete and recreate the shared address resource.

Switch the scalable service resource offline.

Remove the shared address resource from the failover resource group.

Create the shared address resource.

Add the node ID or node name of the node that you removed from the failover resource group to the auxnodelist.
# scrgadm -a -S -g failover-resource-group \ -l shared-address -X new-auxnodelist
failover-resource-group

The name of the failover resource group that used to contain the shared address resource.

shared-address

The name of the shared address.

new-auxnodelist

The new, modified auxnodelist with the desired node added or removed.

Example – Removing a Node From a Resource Group

This example shows how to remove a node (phys-schost-3) from a resource group (resource-group-1), which contains a logical hostname resource (schost-1).

# scrgadm -pvv -g resource-group-1 | grep -i nodelist
(resource-group-1) Res Group Nodelist:       phys-schost-1 phys-schost-2
                                             phys-schost-3
# scrgadm -c -g resource-group-1 -h phys-schost-1,phys-schost-2
# scrgadm -pvv -g resource-group-1 | grep -i netiflist
(resource-group-1:schost-1) Res property name: NetIfList
(resource-group-1:schost-1:NetIfList) Res property class: extension
(resource-group-1:schost-1:NetIfList) List of IP Networking Multipathing 
interfaces on each node
(resource-group-1:schost-1:NetIfList) Res property type: stringarray
(resource-group-1:schost-1:NetIfList) Res property value: sc_ipmp0@1 sc_ipmp0@2
                                                          sc_ipmp0@3

(sc_ipmp0@3 is the IP Networking Multipathing group to be removed.)

# scrgadm -c  -j schost-1 -x  netiflist=sc_ipmp0@1,sc_ipmp0@2
# scrgadm -pvv -g resource-group-1 | grep -i nodelist
(resource-group-1) Res Group Nodelist:       phys-schost-1 phys-schost-2
# scrgadm -pvv -g resource-group-1 | grep -i netiflist
(resource-group-1:schost-1:NetIfList) Res property value: sc_ipmp0@1 sc_ipmp0@2