Configuring an HACMP Cluster

This chapter describes how to configure an HACMP cluster using the SMIT Initialization and
Standard Configuration path.
Have your planning worksheets ready to help you through the configuration process. See the
Planning Guide for details if you have not completed this step.
The main sections in this chapter include:
• Overview
• Configuring a Two-Node Cluster, or Using Smart Assists
• Defining HACMP Cluster Topology (Standard)
• Configuring HACMP Resources (Standard)
• Configuring HACMP Resource Groups (Standard)
• Configuring Resources in Resource Groups (Standard)
• Verifying and Synchronizing the Standard Configuration
• Viewing the HACMP Configuration
• Additional Configuration Tasks
• Testing Your Configuration.
Overview
Using the options under the SMIT Initialization and Standard Configuration menu, you can
add the basic components of a cluster to the HACMP Configuration Database (ODM) in a few
steps. This HACMP configuration path significantly automates the discovery and selection of
configuration information and chooses default behaviors.
If you are setting up a basic two-node cluster, use the Two-Node Cluster Configuration
Assistant to simplify the process for configuring a two-node cluster. For more information, see
the section on Using the Two-Node Cluster Configuration Assistant in the chapter on Creating
a Basic HACMP Cluster in the Installation Guide.
You can also use the General Configuration Smart Assist to quickly set up your application.
You are not limited to a two-node cluster with this Assist.
You can use either ASCII SMIT or WebSMIT to configure the cluster. For more information
on WebSMIT, see Chapter 2: Administering a Cluster Using WebSMIT.
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Prerequisite Tasks for Using the Standard Path
Before using the Standard Configuration path, HACMP must be installed on all the nodes, and
connectivity must exist between the node where you are performing the configuration and all
other nodes to be included in the cluster. That is, network interfaces must be both physically
and logically configured (to AIX 5L) so that you can successfully communicate from one node
to each of the other nodes. The HACMP discovery process runs on all server nodes, not just the
local node.
Once you have configured and powered on all disks, communication devices, serial networks
and also configured communication paths to other nodes in AIX 5L, HACMP automatically
collects information about the physical and logical configuration and displays it in
corresponding SMIT picklists, to aid you in the HACMP configuration process.
With the connectivity path established, HACMP can discover cluster information and you are
able to access all of the nodes to perform any necessary AIX 5L administrative tasks. That is,
you do not need to open additional windows or physically move to other nodes' consoles, and
manually log in to each node individually. To ease this process, SMIT fastpaths to the relevant
HACMP and/or AIX 5L SMIT screens on the remote nodes are available within the HACMP
SMIT screen paths.
HACMP uses all interfaces defined for the connectivity paths to populate the picklists. If you
do not want a particular interface to be used in the HACMP cluster, use the HACMP Extended
Configuration to delete it from the HACMP cluster (this way, it will not be shown up in picklists
and will not be available for selection).
By default, cluster heartbeats are sent through all discovered networks. The network is kept
highly available once it has an HACMP IP label assigned and you synchronize the
configuration.
Assumptions and Defaults for the Standard Path
HACMP makes some assumptions regarding the environment, such as assuming all network
interfaces on a physical network belong to the same HACMP network. Using these
assumptions, HACMP supplies or automatically configures intelligent and default parameters
to its configuration process in SMIT. This helps to minimize the number of steps it takes to
configure the cluster.
HACMP makes the following basic assumptions:
• Hostnames are used as node names. HACMP automatically configures and monitors all
network interfaces that can send a ping command to another network interface. The
network interfaces that can send a ping command to each other without going through a
router are placed on the same logical network. HACMP names each logical network.
• HACMP uses IP aliasing as the default mechanism for binding a service IP label/address to
a network interface. For more information, see the chapter on planning the cluster networks
in the Planning Guide.
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Note: If you cannot use IP aliases because of hardware restrictions, such
as the limited number of subnets that are allocated for cluster
utilization, you will need to use IP replacement to bind your IP
labels to network interfaces. For instance, ATM network does not
support IP aliasing. IP replacement can be configured only under
the SMIT Extended Configuration path (where you disable IP
aliasing).
• IP Address Takeover via IP Aliases is configured for any logical network capable of taking
over a service IP label as an alias. Note, in the Extended Configuration path, you can also
configure IP Address Takeover that uses the IP replacement mechanism for binding IP
labels/addresses with network interfaces.
• You can configure the resource groups with any of the policies for startup, fallover, and
fallback (without specifying fallback timer policies).
• You can configure the application server start and stop scripts, but will need to use the
Extended Configuration path to configure multiple monitors to track the health of each
application server.
Also, since you can add, change, or remove serial (non-IP) networks and devices using the
Extended Configuration path, you must manually define which pair of end-points exist in the
point-to-point network, before adding, changing or removing serial networks and devices.
To manually configure any part of the cluster, or to add more details or customization to the
cluster configuration, use the SMIT HACMP Extended Configuration path. See Chapter 4:
Configuring HACMP Cluster Topology and Resources (Extended) for information on those
options.
Note: If you are using the Standard Configuration path and information that
is required for configuration resides on remote nodes, HACMP
automatically discovers the necessary cluster information for you.
Steps for Configuring a Cluster Using the Initialization and Standard
Configuration Path
Here are the steps to configure the typical cluster components:
What You Do Description
Step 1: Configure a basic
two-node cluster, or a
cluster with WebSphere,
DB2 or Oracle
(Optional) Use the Configuration Assistants panel to
configure any of the following:
• Basic two-node cluster
• Cluster with the WebSphere application
• Cluster with the DB2 UDB instances
• Cluster with an Oracle application server and or Oracle
database instances
• Cluster with another application.
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Step 2: Configure the
cluster topology
Identify the cluster nodes and establish communication
paths between them using the Add Nodes to an HACMP
Cluster menu options. Here you name the cluster and
select the nodes (listed in /etc/hosts) either by their names
or their IP addresses. This gives HACMP the base
knowledge it needs to communicate with the nodes that are
participating in the cluster. Once each node is properly
identified and HACMP obtains information about working
communications paths, HACMP automatically runs a
discovery operation that identifies the basic components
within the cluster.
HACMP uses the discovered hostnames as the node names
and adds them to the HACMP Configuration Database
(HACMPnode ODM). HACMP also automatically adds
the networks and the associated interfaces that share
physical connectivity with two or more nodes in the cluster
to the HACMP Configuration Database (HACMPnetwork
and HACMPadapter ODMs).
Other resource information that HACMP discovers
includes shared disk PVIDs and volume groups.
Step 3: Configure the
cluster resources
Configure the resources to be made highly available. Use
the Configure Resources to Make Highly Available
menu to configure resources that are to be shared among
the nodes in the cluster.
You can configure these resources:
• IP address/IP label
• application server (a collection of start and stop scripts
for the application that HACMP uses)
• volume groups (shared and concurrent)
• logical volumes
• filesystems.
Step 4: Configure the
resource groups
Use the Configure HACMP Resource Groups menu to
create the resource groups you have planned for each set of
related resources. You can configure startup, fallover and
fallback policy for each resource group (without specifying
fallback timer policies).
Step 5: Put the resources to
be managed together into
their respective resource
groups
Use the Configure HACMP Resource Groups >
Change/Show Resources for a Resource Group
(standard) menu to assign resources to each resource
group.
What You Do Description
Configuring an HACMP Cluster (Standard)
Overview
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Step 6: Adjust log viewing
and management
(Optional) Adjust log viewing and management (settings
for the debug level and hacmp.out log file formatting
options per node).
Step 7: Verify and
synchronize the cluster
configuration
Use the Verify and Synchronize HACMP Configuration
menu to guarantee the desired configuration is feasible
given the physical connections and devices, and ensure that
all nodes in the cluster have the same view of the
configuration.
Step 8: Display the cluster
configuration
(Optional) Use the Display HACMP Configuration menu
to view the cluster topology and resources configuration.
Step 9: Make further
additions or adjustments to
the cluster configuration
(Optional) You may want to use some options available on
the Extended Configuration path. Such additions or
adjustments include, for example:
• Adding non-IP networks for heartbeating
• Configuring and changing the distribution preference
for service IP aliases
• Adding other resources to the cluster, such as SNA
communication interfaces and links or tape resources
• Configuring resource group runtime policies, including
Workload Manager
Adding resource group timers
• Configuring dependencies between resource groups
• Adding multiple application monitors for an application
server
• Configuring HACMP File Collections
• Configuring cluster security
• Customizing remote notifications (pager, SMS
messages, and email)
• Customizing cluster events
• Configuring site policies.
Step 10: Test the cluster
before it goes into the
production environment
(Recommended) Use the HACMP Cluster Test Tool to
test recovery procedures for the cluster.
What You Do Description
Configuring an HACMP Cluster (Standard)
Configuring a Two-Node Cluster, or Using Smart Assists
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Configuring a Two-Node Cluster, or Using Smart Assists
You can configure a basic two-node cluster with just a few configuration steps. For information,
see the section on Using the Two-Node Cluster Configuration Assistant in the chapter on
Creating a Basic HACMP Cluster in the Installation Guide.
If you are configuring a WebSphere, DB2 UDB or Oracle application, see the corresponding
HACMP Smart Assist guide.
To configure other applications, you can use the General Configuration Smart Assist.
Limitations and Prerequisites
The initial requirements for using Smart Assists are:
• The application must be installed on all cluster nodes where you want to run it.
• The Smart Assist must be installed on all cluster nodes that run the application.
Configuring Applications with the General Configuration Smart Assist
To configure your installed application (other than DB2, WebSphere, or Oracle):
1. On a local node, enter smitty hacmp
2. Select Initialization and Standard Configuration > Configuration Assistants > Make
Applications Highly Available > Add an Application to the HACMP Configuration
and press Enter.
If the cluster is not yet configured, you are directed to go to the Configure HACMP Nodes
and Cluster SMIT panel. Here you need to list the communication paths to all nodes in the
cluster. Then continue to the next step.
3. If the cluster is configured, SMIT displays a list of applications installed on this node.
Select Other Applications and press Enter.
4. Select General Application Smart Assist and press Enter.
5. Enter values for the following fields on the Add an Application to HACMP panel:
• Application Server Name
• Primary Node
• Takeover Nodes
• Application Server Start Script
• Application Server Stop Script
• Service IP Label.
6. Press Enter after you have filled in the values. The configuration will be synchronized and
verified automatically.
7. (Optional) Return to the panel Make Applications Highly Available to select Test the
HACMP Configuration and press Enter.
The Cluster Test Tool runs and displays results to the screen. If you get error messages,
make the necessary corrections.
Configuring an HACMP Cluster (Standard)
Defining HACMP Cluster Topology (Standard)
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Defining HACMP Cluster Topology (Standard)
Complete the following procedures to define the cluster topology. You only need to perform
these steps on one node. When you verify and synchronize the cluster topology, its definition
is copied to the other nodes.
To configure the cluster topology:
1. Enter smit hacmp
2. In SMIT, select Initialization and Standard Configuration > Configure an HACMP
Cluster and Nodes and press Enter.
3. Enter field values as follows:
4. Press Enter. Once communication paths are established, HACMP runs the discovery
operation and prints results to the SMIT panel.
5. Verify that the results are reasonable for your cluster.
6. Return to the top level HACMP SMIT panel to continue with the configuration.
Cluster Name Enter an ASCII text string that identifies the cluster. The
cluster name can include alphanumeric characters and
underscores, but cannot have a leading numeric. Use no
more than 32 characters. It can be different from the
hostname. Do not use reserved names. For a list of reserved
names see Chapter 7: Verifying and Synchronizing an
HACMP Cluster.
New nodes (via selected
communication paths
Enter (or add) one resolvable IP label (this may be the
hostname), IP address, or Fully Qualified Domain Name for
each new node in the cluster, separated by spaces. HACMP
uses this path to initiate communication with the node.
Example 1:
10.11.12.13 NodeC.ibm.com.
Example 2:
NodeANodeB
(where these are hostnames.)
The picklist displays the hostnames and/or addresses
included in /etc/hosts that are not already
HACMP-configured IP labels/addresses.
You can add node names or IP addresses in any order.
Currently configured
node(s)
If nodes are already configured, they are displayed here.
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Configuring HACMP Resources (Standard)
Using the Standard Configuration path, you can configure the types of resources that are most
often included in HACMP clusters. You must first define resources that may be used by
HACMP to the AIX 5L operating system on each node. Later you group together the associated
resources in resource groups. You can add them all at once or add them separately, as you
prefer.
This section shows how to configure the following components on all of the nodes defined to
the cluster using a single network interface:
• Application servers (a collection of start and stop scripts that HACMP uses for the
application).
• HACMP service IP labels/addresses. The service IP label/address is the IP label/address
over which services are provided and which is kept highly available by HACMP.
• Shared volume groups, logical volumes, and filesystems.
• Concurrent volume groups, logical volumes, and filesystems.
Configuring Application Servers
An HACMP application server is a cluster resource used to control an application that must be
kept highly available. It contains application start and stop scripts. Configuring an application
server does the following:
• Associates a meaningful name with the server application. For example, you could give the
application you are using with the HACMP software a name such as apserv. You then use
this name to refer to the application server when you define it as a resource. When you set
up the resource group that contains this resource, you define an application server as a
resource.
• Points the cluster event scripts to the scripts that they call to start and stop the server
application.
• Allows you to configure application monitoring for that application server. In HACMP 5.2
and up you can configure multiple application monitors for one application server. For
more information see Steps for Configuring Multiple Application Monitors in Chapter
4: Configuring HACMP Cluster Topology and Resources (Extended).
Note that this section does not discuss how to write the start and stop scripts. See the vendor
documentation for specific product information on starting and stopping a particular
application.
Ensure that the server scripts exist on all nodes that participate as possible owners of the
resource group where this application server resides.
To configure an application server on any cluster node:
1. Enter smit hacmp
2. In SMIT, select Initialization and Standard Configuration > Configure Resources to
Make Highly Available > Configure Application Servers > Add an Application Server
and press Enter.