Veritas cluster monitoring

Introduction

High availability enables your IT infrastructure to function continuously though some of the components may fail. High availability plays a vital role in case of a severe disruption in services that may lead to severe business impact.

It is a concept that entails the elimination of single points of failure to make sure that even if one of the components fail, such as a server, the service is still available.

Failover

Failover is a process. Whenever a primary system, network or a database fails or is abnormally terminated, then a Failover acts as a standby which helps resume these operations.

Failover Cluster

Failover cluster is a set of servers that work together to provide High Availability (HA) or Continuous availability (CA). As mentioned earlier, if one of the servers goes down another node in the cluster can take over its workload with minimal or no downtime. Some failover clusters use physical servers whereas others involve virtual machines (VMs).

CA clusters allow users to access and work on the services and applications without any incidence of timeouts (100% availability), in case of a server failure. HA clusters, on the other hand, may cause a short hiatus in the service, but system recovers automatically with minimum downtime and no data loss.

A cluster is a set of two or more nodes (servers) that transmit data for processing through cables or a dedicated secure network. Even load balancing, storage or concurrent/parallel processing is possible through other clustering technologies.

The above image shows an application that runs on a primary or master server. A dedicated redundant server is present to take over on any failure. The redundant server is not configured to perform any other functions. The redundant server is on stand-by with full performance capability.

Veritas Cluster Server (VCS)

Veritas Cluster Server is a high-availability cluster software for Unix, Linux and Microsoft Windows computer systems.

Veritas Cluster Server connects multiple, independent systems into a management framework for increased availability. Each system or node runs its own operating system and cooperates at the software level to form a cluster. VCS links commodity hardware with intelligent software to provide application failover and control. So when a node or a monitored application fails, other nodes take over and bring up services elsewhere in the cluster.

How VCS detects failure

VCS detects failure by issuing specific commands or scripts to monitor the overall health of an application. VCS also determines the health of underlying resources supporting the application, such as network interfaces or file systems.

VCS uses a redundant network heartbeat to differentiate between the loss of a system and the loss of communication between systems.

How VCS ensures application availability

When VCS detects an node or application failure, VCS brings application services up on a different node in a cluster. VCS virtualizes IP addresses and system names, so client systems continue to access the application without any interruption.

Integration is done with Veritas cluster using SSH and shell script.

Pre-requisites

• OpsRamp Classic Gateway 10.0 and above (or) OpsRamp Cluster gateway

• Ensure that “adapter integrations” add-on is enabled in client configuration. Once enabled you can see Veritas Cluster integration under Setup -> Integrations -> Adapter section

• It is mandatory to provide administrator (or) operator level VCS credentials in input configuration. VCS credentials are required to fetch veritas_cluster_group_State, veritas_cluster_group_Status, veritas_cluster_node_State, veritas_cluster_resource_State, veritas_cluster_resource_Status, veritas_cluster_group_failover_Status metric details.

• In order to get Additional metrics ( veritas_cluster_lltLinks_State, veritas_cluster_lltInterface_Status), you need to provide permissions for the non-root SSH user. So, you need to make an entry as below in “/etc/sudoers”.

      cat /etc/sudoers
      Allow root to run any commands anywhere 
      root  ALL=(ALL)     ALL
  
      content  ALL=NOPASSWD:/usr/sbin/lltstat -n,/usr/sbin/lltstat -nvv configured
  
      

• In case root SSH Credentials are provided, no need to configure 2nd prerequisite.

• All nodes IP Address should be publicly available or it should be configured in “/etc/hosts” of all the existing nodes in the Veritas cluster.

      cat /etc/hosts
  
      [root@centos-node1 ~]# cat /etc/hosts
      127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
      ::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
      172.26.1.25 centos-node1
      172.26.1.26 centos-node2
  
      

• non-root user running VCS commands must have a home directory on the system on which the VCS commands will be run.

      pwd
      [content@centos-node1 ~]$ pwd
      /home/content
  
      

Install the integration

1. From All Clients, select a client
2. Go to Setup > Integrations > Integrations
3. From Available Integrations, select Adapter > Veritas Cluster. The Install Veritas Cluster Integration popup appears.
   Note: Ensure that Adapter addon is enabled at client and partner levels.

4. Enter the following information:
   a. Name: Name of the integration
   b. Upload Logo: Optional logo for the integration.
   c. GateWay Profiles: Select a gateway management profile to associate with the client.
   
5. Click Install. The Integration page displays the installed integration.

Configure the integration

1. In CONFIGURATION section, click +Add.
2. On Create Adapter Configuration, enter:
   • Name: Configuration name.
   • IP Address/Host Name: IP address or host name of the target.
   • Notification Alerts: Select TRUE or FALSE.
3. From the SSH Credentials section, select Custom and enter Username and Password. These credentials are required to communicate with the target (cluster).
4. From the VCS Credentials section, select Custom and enter Username and Password. These credentials are required to fetch cluster related information.
5. From the Resource Types & Metrics section, select the metrics and configure for availability and alert conditions, for Cluster & Server.
6. In the Discovery Schedule section, configure how frequently the discovery action should trigger. Select Recurrence Pattern to add one of the following patterns:
   • Minutes
   • Hourly
   • Daily
   • Weekly
   • Monthly
7. In the Monitoring Schedule section, configure how frequently the monitoring action should trigger.

8. Click Save.

After saving the configuration, the resources are discovered and monitoring is done as specified in the configuration profile.

The configuration is saved and displayed on the page.

You can perform the actions manually, like Discovery, Monitoring or even Disable the configuration.

The discovered resource(s) are displayed in the Infrastructure page under “Cluster”, with Native Resource Type as Veritas Cluster.

The cluster nodes are displayed under Components:

Supported Metrics

Resource Type: Cluster

Resource Type: Cluster Nodes

Supported product versions: Supported versions are Veritas infoscale 7.4.2

Risks, Limitations & Assumptions

• As of now supporting only Linux based Veritas failover cluster
• When we add two configurations with same end device details (like IP, credentials), we might observe gaps in the graphs due to internal VCS login and logouts parallely on the same device