4.2 OES Cluster Services Configuration and Setup

4.2.1 Prerequisites

OES Cluster Services must be installed and running on the servers that have NetStorage installed before performing the remainder of the NetStorage and OES Cluster Services configuration. For information, see Installing, Configuring, and Repairing OES Cluster Services in the OES 2018 SP2: OES Cluster Services for Linux Administration Guide.

IMPORTANT:Because NetStorage is installed and configured identically on the cluster servers where it will run and because that configuration information is stored on each server, no shared storage is required to run NetStorage with OES Cluster Services.

4.2.2 Creating a NetStorage Cluster Resource

A cluster resource containing a secondary IP address is necessary to ensure that users continue to have access to NetStorage if a server running NetStorage goes down.

OES Cluster Services includes a Generic IP Service resource template, which simplifies the process for creating a NetStorage cluster resource.

  1. Start your Internet browser and enter the URL for iManager.

    The URL is https://server_ip_address/nps/iManager.html. Replace server_ip_address with the IP address or DNS name of a server in the cluster or with the IP address for Apache-based services.

  2. Enter your username and password.

  3. In the left column, click Clusters, then click the Cluster Options link.

    iManager displays four links under Clusters that you can use to configure and manage your cluster.

  4. Browse to locate and select the Cluster object of the cluster you want to manage, then click the New link.

  5. Specify Resource as the resource type you want to create by clicking the Resource radio button, then click Next.

  6. Specify a name for the NetStorage cluster resource that you want to create.

    Do not use periods in cluster resource names. Client for Open Enterprise Servers interpret periods as delimiters. If you use a space in a cluster resource name, that space is converted to an underscore.

  7. In the Inherit From Template field, select the Generic_IP_Service template.

  8. Select the Define Additional Properties check box, then click Next.

  9. Select the Define Additional Properties check box, click Create, and then continue with Section 4.2.3, Editing NetStorage Load, Unload and Monitor Scripts.

    The Generic IP Service template helps configure the NetStorage cluster resource by automatically creating load and unload scripts, setting failover and failback modes, and assigning the resource to all nodes in the cluster.

    You should only assign the resource to those nodes in the cluster that have NetStorage installed and running.

4.2.3 Editing NetStorage Load, Unload and Monitor Scripts

The Generic IP Service resource template automatically creates load and unload scripts to start and stop the NetStorage resource on servers in your cluster. The load script contains commands that you must customize for your specific NetStorage configuration.

If you are creating a new cluster resource, the load script page should already be displayed.

  1. In iManager, click Clusters, then click Cluster Options.

  2. Browse to locate and select the Cluster object of the cluster you want to manage.

  3. Select the check box next to the resource whose load script you want to edit, then click the Details link.

  4. Click the Scripts tab, then click the Load Script link. Edit the load script for your specific configuration.

    The default load script is:

    #!/bin/bash
    . /opt/novell/ncs/lib/ncsfuncs
    
    # define the IP address
    RESOURCE_IP=a.b.c.d
    
    # add the IP address
    exit_on_error add_secondary_ipaddress $RESOURCE_IP
    
    # start the service
    exit_on_error systemctl start myservice.service
    
    # return status
    exit 0
  5. Click the Scripts tab, then click the UnLoad Script link. Edit the unload script for your specific configuration.

    #!/bin/bash
    . /opt/novell/ncs/lib/ncsfuncs
    
    # define the IP address
    RESOURCE_IP=a.b.c.d
    
    # request service stop
    ignore_error systemctl stop myservice.service
    
    # del the IP address
    ignore_error del_secondary_ipaddress $RESOURCE_IP
    
    # return status
    exit 0 
  6. Click the Scripts tab, then click the Monitor Script link. Edit the monitor script for your specific configuration.

    #!/bin/bash
    . /opt/novell/ncs/lib/ncsfuncs
    
    # define the IP address
      RESOURCE_IP=a.b.c.d
    
    # check the IP address
      exit_on_error status_secondary_ipaddress $RESOURCE_IP
    
    # check the service
      exit_on_error systemctl status myservice.service
    
    # return status
      exit 0 
  7. Continue with Section 4.2.4, Setting the NetStorage Resource Start, Failover, and Failback Modes.

4.2.4 Setting the NetStorage Resource Start, Failover, and Failback Modes

A cluster resource cannot be edited while it is loaded or running on a server. Make sure to offline the resource before attempting to modify its resource properties, policies, or scripts.

The Generic IP Service resource template sets the NetStorage resource Start Mode and Failover Mode to AUTO, and the Failback Mode to DISABLE.

If the NetStorage resource Start Mode is set to AUTO, the resource automatically starts on a designated server when the cluster is first brought up (the secondary IP address specified in the resource is automatically added to the server). If the NetStorage resource Start Mode is set to MANUAL, you can manually start the resource on a specific server when you want, instead of having it automatically start when servers in the cluster are brought up.

If the NetStorage resource Failover Mode is set to AUTO, the NetStorage resource automatically moves to the next server in the Assigned Nodes list in the event of a hardware or software failure. If the NetStorage resource Failover Mode is set to MANUAL, you can intervene after a failure occurs and before the resource is started on another node.

If the NetStorage resource Failback Mode is set to DISABLE, the resource continues running on the node it has failed to. If the NetStorage resource Failback Mode is set to AUTO, the resource automatically moves back to its preferred node when the preferred node is brought back online. Set the NetStorage resource Failback Mode to MANUAL to prevent the resource from moving back to its preferred node when that node is brought back online, until you are ready to allow it to happen.

The preferred node is the first server in the Assigned Nodes list for the resource.

IMPORTANT:Resources fail back only to the first node in their Assigned Nodes list. For example, if a resource has failed over to three servers since it originally ran on its preferred node, and the second server the resource was running on comes back up, the resource does not fail back to that second server.

Resources do not automatically move from node to node just because a node higher in the Assigned Nodes list rejoins the cluster, unless the Failback mode is set to AUTO and the first node in the Assigned Nodes list rejoins the cluster.

If you are creating a new cluster resource, the Resource Policies page should already be displayed. You can start with Step 5.

  1. In iManager, click Clusters, then click Cluster Options.

  2. Browse to locate and select the Cluster object of the cluster you want to manage.

  3. Select the box next to the resource whose Start, Failover, or Failback modes you want to view or edit, then click the Details link.

  4. Click the Policies tab.

  5. (Conditional) Select the Resource Follows Master check box if you want to ensure that the resource runs only on the master node in the cluster.

    If the master node in the cluster fails, the resource fails over to whichever node becomes the master.

  6. (Conditional) Select the Ignore Quorum check box if you don’t want the cluster-wide timeout period and node number limit enforced.

    The quorum default values were set when you installed OES Cluster Services. You can change the quorum default values by accessing the properties page for the Cluster object.

    Selecting this box ensures that the resource is launched immediately on any server in the Assigned Nodes list as soon as any server in the list is brought online.

  7. Specify the Start, Failover, and Failback modes for this resource.

    The default for both Start and Failover modes is AUTO, and the default for Failback mode is DISABLE.

  8. Continue with View or Edit NetStorage Resource Server Assignments, or if you are creating a new cluster resource, click Next, then continue with Configuring NetStorage with OES Cluster Services.

4.2.5 View or Edit NetStorage Resource Server Assignments

Changes that you make to a cluster resource’s properties, policies, and scripts are not applied until the resource is unloaded, and then loaded again. Make sure to offline the resource, and then online the resource to activate the changes.

The Generic IP Service resource template automatically assigns the NetStorage resource to all nodes in the cluster. The order of assignment is the order the nodes appear in the resource list. You should assign the NetStorage resource only to those servers in the cluster that have NetStorage installed.

If you are creating a new cluster resource, the Preferred Nodes page should already be displayed. If you are assigning nodes for an existing resource, the Preferred Nodes page is displayed as part of the Resource Policies page. You can start with Step 5.

  1. In iManager, click Clusters, then click Cluster Options.

  2. Browse to locate and select the Cluster object of the cluster you want to manage.

  3. Select the box next to the resource whose preferred node list you want to view or edit, then click the Details link.

  4. Click the Preferred Nodes tab.

  5. View the current NetStorage resource server assignments and, if necessary, click the right-arrow or left-arrow button to assign or unassign servers to the resource.

    The Assigned Nodes list should contain only servers where you have installed and configured NetStorage.

  6. View the order of the NetStorage resource server assignments and, if necessary, click the up-arrow and down-arrow buttons to change the preferred failover order of the servers assigned to the resource or volume.

  7. Click Apply to save node assignment changes.

4.2.6 Accessing NetStorage After Cluster Configuration

To access NetStorage after configuring it with OES Cluster Services, use the NetStorage cluster resource IP address as part of the URL to access NetStorage instead of the NetStorage server’s IP address or DNS name. For more information on accessing NetStorage, see Section 6.0, Using NetStorage.