Configuring Alloy for server clustering and Web services call failover
Alloy™ by IBM® and SAP® provides server clustering and failover support in a Lotus Notes and Domino environment.
In this configuration, the Alloy server installation program is run on each participating Domino (Alloy) server in the cluster and the Web services application (NDERPws.nsf) is correctly configured on the primary Alloy server and replicated to all other Alloy servers in the cluster.
One Alloy server is designated as the primary server. Failover is available for secondary servers in the cluster. If the primary server goes down, the entire Alloy cluster becomes unavailable until the primary server is restarted.
Note: Server failover for processing in Lotus Notes and Domino is not supported when the primary Alloy server (the Domino server on which the primary Web services application resides) is offline. No Alloy processing, including metadata processing or request/approval processing, occurs when the primary Alloy server is offline.
Load balancing and failover of the Web services application (NDERPws.nsf) is supported in the following cluster configuration:
- The Alloy server installation program is run on all Domino servers in the cluster.
- A single Alloy server is designated as the primary Alloy server, all other Alloy servers in the configuration are secondary.
- The Web services application (NDERPws.nsf) is created and configured on the primary Alloy server.
Note: The primary Alloy server is also responsible for handling document locking for the Web services application replicas in the cluster. To ensure high availability of this server,use OS-level clustering with an active/passive mode for this server. The administrator can transition from active mode to the passive mode as needed.
- Domino standard cluster replication is enabled.
- The Web services application (NDERPws.nsf ) is replicated from the primary server to each Alloy server in the cluster by way of Domino standard cluster replication.
- A valid IP Sprayer or Port Forwarder, such as the IBM Edge Network Dispatcher, is resident in the cluster.
- The primary server must remain running; any other server in the cluster can go down and its Web service calls will fail over to another Alloy server in the cluster, provided that the primary server remains running. All Web service call failover stops if the primary server stops running.
- Alloy clients are configured to recognize the primary server using two preferences in the Notes plugin_customization.ini file.
Configuring Alloy servers for clustering and failover
Install and configure Alloy by IBM and SAP servers and the Web services application (NDERPws.nsf) for clustering and failover in the Notes and Domino environment.
For information related to Alloy server install and configuring the Web services application, see "Installing the Alloy server on a Domino server" and "Setting configuration values in the Web services application" in the Alloy by IBM and SAP Administrator Guide.
1. Run the Alloy server installation program on each separate Domino server in the cluster but do not create and configure the Web services application (NDERPws.nsf) yet.
2. Choose one Alloy server to be the primary server in the cluster.
3. Enable Domino standard cluster replication; see the "Clusters" section and topics such as "Managing failover in a cluster" and "Configuring and controlling cluster replication" topics in Domino Administrator help at http://publib.boulder.ibm.com/infocenter/domhelp/v8r0/index.jsp.
4. Create and configure the Web services application on the primary Alloy server.
5. Perform this additional step in the Web services application on the primary Alloy server.
a. Open the Web services application (NERPws.nsf).
b. Click Applications in the left pane navigator.
c. Click Open Server Config.
d. Scroll to Cluster Information.
e. Click Yes if Web services application is to participate in server clustering and failover.
f. Specify the primary server name and address in the Primary Cluster Server field.
g. Set the SAP SAML configuration settings for the primary Alloy server.
6. Click File -> Application -> Access Control and in the Attributes section, add the server IDs of all the Alloy servers in the cluster, as follows. Add each server ID to the Admin role:
- User type -Server
- Access level - Manager
- Roles - [admin]
- Delete Documents - enable the option
Note: Even though the default ACL for NDERPws.ntf grants Manager access to the LocalDomainServers group, the NDERPws.nsf on each Alloy server in the cluster requires that each Alloy server is specifically added to its ACL with the Admin role.
7. Click OK to close the access control list dialog.
8. Click Application -> Properties and enable Allow Document Locking.
9. Exit the Web services application. Allow the Web services application to replicate from the primary server to each Alloy server in the cluster by way of standard cluster replication.
10. Configure the IP Sprayer and Alloy clients as described in the next tasks.
Configuring an IP Sprayer for Alloy server clustering and failover
Install and configure a valid IP Sprayer or Port Forwarder in the Alloy by IBM and SAP server cluster to support Web services call load balancing and failover.
The IP Sprayer is used to port forward HTTP and HTTPS. an IP Sprayer load balances between the servers in the cluster. The IBM Edge Network Dispatcher is a recommended product. You can install the IP sprayer on an independent server or on any Alloy Domino server in the cluster.
Note: Alloy clustering does not support use of Internet Cluster Manager (ICM). An IP Sprayer or Port Forwarding tool such as IBM Edge Network Dispatcher or any third party IP Sprayer is required.
1. Set the IP Sprayer to port forward HTTP on Port 80.
2. Set the IP Sprayer to port forward HTTPS on Port 443.
3. In SAP, direct the SAP Item Handler to use the cluster IP address.
Note: The IP Sprayer uses a cluster IP address to assist with load balancing. Use that cluster IP address for all references to Web services calls to the Web services application on the primary Alloy server.
Configuring Alloy clients for clustering and failover
Alloy clients are configured to recognize the primary server using settings in the Notes plugin_customization.ini file.
Depending on how you install the Alloy client plug-in for Notes users, the plugin_customization.ini file on the client must contain two specific settings.
Note:There are many ways to add plugin_customization settings, including the Managed Setting tab in the Domino desktop policy settings document, the plugin_customization.ini file supplied in the Notes install kit or in the Alloy client plug-in add-on installer kit, by passing arguments during a command line install, or by manually adding the settings to the installed plugin_customization.ini file in the Notes_install_dir\framework\rcp folder.
Specify the Alloy cluster address, configured in the IP Sprayer, by adding the following settings to each Alloy client's plugin_customization.ini file.
These settings should be part of the plugin_customization.ini file when you install the Alloy client plug-in.
- com.ibm.nderp.client/NDERPMDWS_URL=http://Cluster Address/NDERPws.nsf/MetaDataService?openwebservice
The NDERPMDWS_URL value points to the Web services application using the cluster address rather than the server address of the primary Alloy server.
The NDERP_PrimaryServer points to the primary Alloy server as specified in the Web services application.
Note: For information about using policy to push managed settings to users, see "Pushing Eclipse managed settings to Notes users" in Domino Administrator help.
Note: For related IP sprayer information, see "Configuring an IP Sprayer for Alloy server clustering and failover" in this post.