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Regarding Apache agent

Created: 29 Oct 2012 • Updated: 30 Oct 2012 | 6 comments
This issue has been solved. See solution.

Hi experts,

I am very new to VCS. I have tried setting up the cluster with your help. Now I want to create sample apache servicegroup. I am bit confused between Servicegroup, resources and agent. I can see reference of  IP resource also and IP agent also. I dont know whether

I should configure an apache servicegroup and add IP, mount , filisystem resources into it

or

I should configure an apache agent having IP , mount.filesystem agents.

Could you please guide me.

Thanks a lot in advance.

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Marianne's picture

The VCS Bundled Agent Guide is your friend.

If you tell us your VCS version and OS, we can help you find the right manual for your version and OS. 
Else, go to https://sort.symantec.com/documentation, scroll down to Veritas Cluster Server section and select Product Guides for your OS and version.

In Bundled Agent Guide 6.0 for Solaris, information of how to configure Apache agent can be found in chapter 5 (Services and Applications agents). 

Look at Dependencies under Apache HTTP server agent topic.

You will also find Sample configurations at the end of this section.

Hope this helps!

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

priyanka3rdfeb@gmail.com's picture

Thanks for the reply. I am alreday refering Bundled Agent Guide 6.0.  I am confused between terms Agent and Resource. I dont know when should I configure agent and when should i configure resource. We have IP agent and IP resource also. Could you please help me.

I am using VCS 6.0 and Redhat 6.1.

Marianne's picture

Symantec is providing you with built-in agents. Apache is one of them.

To understand the difference between Agent and Resource, see the topics in Chapter 1 of Bundled Agents:

About Bundled agents

Bundled agents are Veritas Cluster Server (VCS) processes that manage resources
of predefined resource types according to commands received from the VCS
engine, HAD. You install these agents when you install VCS.
A node has one agent per resource type that monitors all resources of that type.
For example, a single IP agent manages all IP resources.
When the agent starts, it obtains the necessary configuration information from
VCS. The agent then periodically monitors the resources, and updates VCS with
the resource status.
Agents can:
■ Bring resources online.
■ Take resources offline.
■ Monitor resources and report state changes.
For a more detailed overview of how agents work, refer to the Veritas Cluster
Server Administrator’s Guide.
 
Resources and their attributes
Resources are parts of a system. They are known by their types, for example: a
volume, a disk group, or an IP address. VCS includes a set of resource types.
Different attributes define these resource types in the types.cf file. Each type has
a corresponding agent that controls the resource.
... (more in the manual) ....
 
So, all you need to configure are resources in your Service Group.
 
Look at the sample resource tree under Dependencies topic:
 
Apache resource requires IP and Mount resources.
IP requires a NIC resource
Mount requires a Volume resource
Volume requires a DiskGroup resource
 
Suggestion:
Before you attempt to configure this Service group, please take a day or two to read through the Cluster Admin Guide for an understanding of the basic consepts?
 
 

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

Jubin's picture

Hi,

My two cents,

Service groups, resources types, agents are few components of VCS that provide the infrastructure to cluster an application.

For more information on service groups, resource types, agents in VCS, see Logical components of VCS, which is part of the VCS Administrator's Guide.

Difference between VCS agents and resources, in brief:

Resources are objects that related to hardware and software. They are controlled or monitored by VCS, for example, IP resource, Mount resource and so on. Each resource corresponds to a VCS agent which actually handles VCS control over the resource.

Bundled agents (you install these when you install VCS) are Veritas Cluster Server (VCS) processes that manage resources of predefined resource types according to commands received from the VCS engine.

Suggested references: VCS Bundled Agents Reference Guide, VCS Administrator's Guide

Thanks,

Jubin

mikebounds's picture

You said:

I dont know when should I configure agent and when should i configure resource

You don't really configure agents.  For each resource type in your main.cf, like IP, Mount and Apache, there is a single "Agent" process that controls all resources of that type and this agent knows how to start, stop, monitor and clean resources of that type, so a Mount agent knows to run "mount" command to start a mount and the Apache agent knows to run "httpd" binary to start an Apache resource.

So first you create a service group - this is a container for your resources so that these resources move as one unit from one node to another and it is what resources are contained in the service group that define what the service groups controls, so if the service group contains Apache IP and Mount resources it means the service group controls Apache and Oracle Mount and IP resource would mean it would control Oracle.

Then you create resources of a particular type in your service group, like Apache, and configure resource attributes like "httpdDir" and "ConfigFile" for each resource.  So for a resource of type Mount you would configure attributes like MountPoint and BlockDevice and for multiple Mountpoints you would create multiple resources, one for each Mount.  

You can also configure "Resource Type" attributes and these are configured per agent and are generally the timeouts and restarts and so if you, for example, run "hatype -display Apache", you will see agent attributes such as "OnlineTimeout" and "RestartLimit" and changing these attributes (using hatype -modify AgentName) will effect ALL resources of this agent type.  You probaly only have one Apache reosurce, but if you have several Mount resources, and you changed the RestartLimit, then this would effect ALL Mount resources.  

Mike

UK Symantec Consultant in VCS, GCO, SF, VVR, VxAT on Solaris, AIX, HP-ux, Linux & Windows

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priyanka3rdfeb@gmail.com's picture

Thanks a lot Mike and others for clearing my doubts.