NDS iMonitor: NDS Monitoring and Diagnostic Tool, Part 2

Articles and Tips: article

Tom Doman

Duane Buss

Steve McLain
Novell, Inc.

01 Apr 2003

Tom Doman

Duane Buss

Steve McLain

Novell, Inc.

Last month we started a series of columns written by three NDS Architects who have great knowledge about the NDS iMonitor utility. This month we'll continue with this investigation of NDS iMonitor from the view of those who envisioned and created it.

Modes of Operation

NDS iMonitor can be used in two different modes of operation: Direct mode and Proxy mode. No configuration changes or special user intervention is required to move between these modes because iMonitor can switch between them automatically. These modes should be understood, however, in order to successfully navigate an NDS eDirectory tree and to correctly interpret what is presented in all iMonitor pages.

Direct Mode.

iMonitor uses direct mode when its executable is gathering information or is providing a feature from the same physical server where the NDS Agent executable resides and therefore where the local NDS eDirectory DIB is located. This mode is important because some iMonitor features are only available in direct mode. These features are also referred to as server-centric.

In more technical terms, no remote access (proxy) method (which exposes the desired functionality) is available in direct mode. In practical terms, to have access to server-centric features on your servers, you must upgrade them to at least eDirectory 8.5. As mentioned last month, this version of eDirectory includes the first version of iMonitor.

All iMonitor features are available while in direct mode. The few features that are server-centric will be detailed under the "Features" heading. Direct mode is also important because it provides you faster access to information than that afforded by proxy mode.

Key features of direct mode include:

Full server-centric feature set.
Reduced network bandwidth (faster access than proxy).
Access by proxy still available for older versions of NDS.

Proxy Mode.

iMonitor uses proxy mode when its executable is gathering information remotely from a different server than the one iMonitor is running on. This mode allows monitoring and diagnostic information to be gathered from previous versions of NDS eDirectory and NDS all the way back to NDS build version 6.x. The vast majority of iMonitor features will, at least, be requested of the remote NDS agent by proxy. These features are detailed under the "Features" heading.

The only factor affecting your access of iMonitor features while in proxy mode is the version of the NDS agent that iMonitor is accessing. As a general rule, the older the agent version, the greater the chance that version will not support the request made.This is simply the result of iMonitor's monitoring and diagnostic capabilities for the latest features implemented in eDirectory. Older versions of NDS either did not contain these features or the information was not exposed in those versions.

Either way, if the remote NDS agent does not support the request made, it will provide some indication of this fact and you will see either an error code or just fewer options. This, coupled with access to server-centric or direct mode-only features, is a compelling reason to upgrade to eDirectory 8.5 or later on as many servers as is feasible. This will allow you to take full advantage of the power of iMonitor.

Proxy mode is the default behavior of iMonitor. It is assumed that once you have established communication with an instance of iMonitor, that is where you wish to stay. All features or hyperlinks pertaining to other NDS agents in your tree will be done in proxy mode. This is true even for eDirectory 8.5 or later NDS agents, unless you explicitly switch to another iMonitor instance and then initiate direct mode.

Key features of proxy mode include:

Not every server in the tree must be running NDS iMonitor in order to use most of iMonitor features.
Only one server is required to be upgraded to eDirectory 8.5 or later.
There is a single point of access for dial-in.
You can access iMonitor over a slower speed link while iMonitor accesses NDS information from other servers over higher speed links.
Previous NDS versions are monitorable and diagnosable.
Server-centric features are only available where iMonitor is installed and loaded.

NDS iMonitor Modes Expanded

iMonitor's choice of mode is entirely dependent on the URL that your browser submits. A URL with a "server" query in it will use proxy mode. For example, http://myserver.mycompany.com/nds/agent? server=myotherserver.mycompany.com , will use proxy mode to gather information from myotherserver.mycompany.com as it corresponds to the "nds/agent" page or feature.

URLs with no server query will use direct mode access. Actually, you could think of direct mode as having an implied server query that uses the same address as the one used to access iMonitor. In other words, the local NDS agent is used if no server query is specified.

This type of query, as well as many others (which you can create and/or modify manually) are all discussed in detail in the following table. In many browsers, mousing over a hyperlink will display the URL that will be submitted if clicked. It's useful to know whether your favorite browser supports this behavior, as it will provide you with an indication of whether proxy mode is employed or not if that link is followed. iMonitor will also provide you with several visual clues in the Navigator frame that indicate which mode your are in and that will help you navigate to where you want to be.

Direct Mode.

On most pages you will see an icon indicating the status of the local NDS agent (open, initializing, closed, locked, etc.). iMonitor obtains this status via a non-proxyable or local method, which implies direct mode access. Other pages simply display the fully distinguished name of the NDS agent being used to gather the requested data in the "Server" field.

If the displayed NDS agent's distinguished name (the "NCP Server" DN) represents the same server where the iMonitor you are accessing is running, then you are in direct mode. When you are in direct mode, you will also see icons that give you access to server-centric features.

Proxy Mode.

While you are in proxy mode, direct mode only or server-centric feature links will disappear from all of your iMonitor pages. However, depending on the version of NDS you are proxying, you may see new navigational icons in the Navigator frame.

For instance, if you are proxying an NDS eDirectory 8.5 or later version, you will see a "Remote iMonitor" icon if iMonitor is loaded on the remote server. If clicked, it will take you to the iMonitor running on the remote server. In other words, this has the affect of switching you from proxy mode to direct mode for the server you were proxying.

Any time you switch from direct mode in one iMonitor instance to direct mode access on another iMonitor server, you will need to reestablish your identity by logging in, using the Login icon in the Navigator frame if you are not automatically prompted to do so. The latest versions of iMonitor 1.5 and all versions of iMonitor 2.0 automatically prompt you to establish a non-public identity (i.e., login) by default unless you have modified your configuration file to allow iMonitor to permit .[Public]. access. While all versions of iMonitor support configuration of this feature, earlier version defaulted to allow .[Public]. access.

You will not have to re-login if you are using the.[Public]. identity or if you have already logged in to the desired iMonitor instance without restarting your browser in between. iMonitor is able to detect whether the remote server has an instance of iMonitor loaded because each iMonitor adds an NDS referral for itself to the local NDS agent when it loads.

This is exactly what the LDAP server and the NetWare Remote Manager do when they load. Because the NetWare Remote Manager registers an NDS referral, iMonitor can also provide a link to Portal in the Navigator frame for greater ease of navigation. When you are in proxy mode, you will also see a "Home" icon in the Navigator frame, which will switch you from proxy mode on one NDS agent back into direct mode for the NDS agent where iMonitor is running.

Features

In the past, when you needed to inspect the health of your NDS eDirectory tree, you probably had to remote console into or physically visit several servers and use one or more server-based NDS utilities to get the detailed information that you needed. But often the information you needed would scroll off the screen before you could read it or you would find the information you were looking for but you had to go to another tool to fully diagnose the situation. Perhaps you uncovered an error that was occurring but you didn't know what it meant, what could cause it, nor how to handle it.

As mentioned earlier under the "Modes of Operation" heading, there are two classes of features in iMonitor: server-centric or direct mode only, and remote or proxy-accessed features. Remember, if no server query is specified in the URL submitted to iMonitor, the specified server for the given feature is implied to be the NDS agent local to iMonitor. The following is a complete list with a short description of all iMonitor features and sub-features based on class.

Remoteable Features	Agent Definition
NDS Agent Health
NDS Agent Health Summary (/nds or /nds/summary)	The root page for NDS information that summarizes three different agent health-related features into one page: Synchronization, Known Servers, and Agent Process Status. This page can be used to access all other iMonitor features.
Server Synchronization (/nds/ssync)	Summarizes the synchronization status of all replicas for the specified NDS agent.
Replica Synchronization (/nds/rsync?dn=...)	Details synchronization information and status for a particular replica from the perspective of the specified NDS agent.
Known Servers (/nds/known)	Provides a list of servers (or NDS agents) known to the specified NDS agent. Displays status and version for each server listed.
Agent Process Status (/nds/pstatus)	Provides detailed information regarding errors that may have occurred during certain NDS background processes in the specified agent.
NDS Agent Health Checks (/nds/health)	Summarizes health information about the specified NDS Agent and the partitions and the replica rings in which it participates. Additional links provide more detailed information as you follow them.
NDS Agent Browse
Object Browse (/nds/object?dn=...) (/nds/list?dn=...)	The object URL allows NDS objects and their attributes to be examined from the perspective of the specified NDS agent. For the list URL, if the specified DN is a container, its contents will be listed from the perspective of the specified NDS agent.
Schema Browser (/nds/schema) Schema Synchronization List Attribute Definitions Class Definitions	Allows you to access NDS schema information for the specified NDS agent and compare its schema with other NDS agents.
NDS Agent Configuration
Agent Configuration (/nds/agent) Agent Information Partition List Replication Filters Agent Triggers Background Process Settings Agent Synchronization Control Schema Synchronization Control Database Cache Settings Login Settings	Provides access to various types of configuration information about the specified NDS agent. You can also modify some of the parameters and control some background processes.
NDS Agent Activity
Agent Activity (/nds/activity) Verbs Current DIB lock and Verb Activity Statistics Synchronization Current Activity Schedule Events Current Activity Statistics Rights Background Process Schedule	Shows various aspects of the specified NDS Agent's current and historical activity, including Verbs (Requests), DIB Writers, Synchronization, Events, and Background Processes.
NDS General
Search (/nds/search)	Provides a method to search for objects in NDS that meet the specified criteria.
DirXML Detail (/nds/dirxml)	Provides detailed and summary information regarding DirXML drivers in your system, their status and configuration, and the objects that are associated with them.
Reports (/nds/reports) Server Information (Treewide w/ Agent Health Sub-Report) Obituary Listing Object Statistics Service Advertising Agent Health Custom	Schedulable reporting mechanism with both preconfigured and customizable reports.
Error Information (/nds/error)	Provides an index as well as detailed information about error codes--their possible causes and solutions.
Server-Centric Features
NDS Trace (/nds/trace) Trace Configuration Event Configuration Trace Triggers Trace History Live Trace	A hyperlinked, web-browser-based version of DS Trace.
NDS Repair (/nds/repair)	A simple, web-based version of DS Repair.
About iMonitor (/nds/about)	This page presents version and other information about the iMonitor executable.

Conclusion

This month we looked at the two basic modes of NDS iMonitor: Direct mode and Proxy mode. Direct mode is used when gathering information from the immediate physical server that iMonitor is running on. Proxy mode is used when NDS iMonitor is gathering information about a server that is different from the one that it is running on. Next month, we will discuss the anatomy of an NDS iMonitor Query and go into more detail about the NDS iMonitor Agents.

* Originally published in Novell AppNotes

Disclaimer

The origin of this information may be internal or external to Novell. While Novell makes all reasonable efforts to verify this information, Novell does not make explicit or implied claims to its validity.