Comparing the history of nodes

The historical comparison facility enables you to compare any like nodes in BMC Helix Discovery to identify and monitor differences over time. For example, you can display two selected nodes side by side to see where the differences are or which parts are unique to that particular version. The various results are color coded to make them easy to identify.

Related topics

Performing basic tasks

Viewing a host

The historical comparison facility applies to any kind of node (object) in the system. However, the following examples illustrate the various views and comparison options that are available for a selection of host nodes in BMC Helix Discovery. For more information about attributes and relationships for the following examples, see Viewing a host.

Historical comparison of an entire node

You can view details of the history of an entire node and display details of how the node has changed over time, including changes made, the date and time of the changes, the names of the users who made the changes, and so forth.

To view a node for historical comparison

Display the View Object page of the relevant node (for example, a host).
From the Actions list, select View History.
The Historical Comparison page is displayed for the node you have selected.
The default view for the Historical Comparison page initially shows only the attributes that have been changed on this node since it was first created.
Note

Grayed-out cells indicate that no attribute is present.
To display all of the attributes for this particular node, click the Show All Attributes link.
To return to the default view, click the Show Differences Only link.

Historical Comparison page

The Historical Comparison page is divided into the following columns:

Attribute Column—Displays the attributes of this node.
Center Column—Displays a version of the node you have selected for historical comparison. The default view for this column shows the last time that something was amended for this node (that is, version 3 of 4 for this example above).
Right Column—Displays a particular version of the node you have selected for historical comparison. The default view for this column shows the latest version of this node (that is, version 4 of 4 for this example above).

The default view, in the first header row of the right column, shows the most recent state of the node on 18/11/2013 at 10:34 and that it is the forth version of this node (4 of 4). The fact that version 4 of this node is being displayed in the right column is also indicated in the second header row where the number 4 is not underlined.

The second header row enables you to independently change the versions of the node to display different historical comparisons. For example, you might want to compare version 2 (2 of 4) with version 3 (3 of 4) to identify exactly what changed during that period of time.

The blue direction arrows in this row enable you to view earlier or later versions of this node and are configured as follows:

Arrows pointing left—Click once to display the next earlier version.
Arrows pointing right—Click once to display the next later version.

Alternatively, you can click the version number directly in each column. The historical comparison between the two versions that you select is displayed automatically.

Three types of information changes are color-coded and recorded on this page:

Green—The attribute is unique to the node version in the left column.
Yellow—The attribute differs across the selected node versions.
Red—The attribute is unique to the node version in the right column.

Attributes for different nodes in BMC Helix Discovery might vary; however, the first attribute row is Change Made By and is always present. This identifies the user who made the change. Remaining attributes for each node are listed in taxonomy-defined order.

You can also view a separate list of data for certain attributes that shows unique and common items. For this example, to view this information, you can click the links for each version for Patches, Packages, and Network Interfaces. For example, you can click the link in either node version column for the Patches attribute.

This example shows that version (4 of 4) has no items that are unique to that version and 311 items that it has in common with version (3 of 4).
To return to the Communication Links attribute summary view, click the link in either node version column again.

To change the history compression threshold

When using the History view described above, what you are actually seeing is a processed version of the underlying raw data. The historical comparison pages compress the raw history into changes. Entries are grouped by user.

To switch from raw to comparative history views

You choose to view historical changes in their raw form, without the compression described previously. To switch between viewing history modes, click Switch to raw view at the top right of the page.

The view changes to one in which each individual change is output per line.

To change back to the compressed view, click Switch to comparative view.

You can change the type of view you would like to display by default by changing your preferences.

Node to node comparison

You can perform node-to-node comparisons for any kind of node. However, you can compare only like to like (for example, host to host). The comparisons are completely arbitrary and do not need to have a relationship, provided that they are like-for-like nodes.

To select nodes for node to node comparison

Display the View Object page of the relevant host.
The BMC Discovery Host page is displayed.
From the Actions menu, select Compare To.
The Search for Hosts to Compare page is displayed for the node you have initially selected.
You can also change the details of this first host to search for another host.
Click Change.
In the Search for the first Host to Compare pane, type a keyword for the name or IP address of the first host you want to compare.
Select a match type from the list, and click Search.
From the list of results, select a host to compare.
Note

To return at any time to the default details for the first host, click Cancel.
In the Search for the second Host to Compare pane, type a keyword for the name or IP address of the second host you want to compare.
Select a match type of from the list, and click Search.
From the list of results, select a second host to compare against the first host, and click the name of the host.
After you have selected the two hosts that you want to compare, select Compare from the Actions menu.
Note

The width of each displayed column is dependent on the data content of each host.

The node-to-node comparison page is divided into the following columns:

Attribute Column—Displays the attributes of this node.
Center Column—Displays a version of the node you have selected for historical comparison.
Right Column—Displays a particular version of the node you have selected for historical comparison.

The default view, in the first header row of the left and right columns, displays the most recent state of each separate node.

The second header row enables you to independently change the versions of each separate node to enable you to display different historical comparisons. For example, you might want to compare version 3 of de-32-R8-2 with version 27 of lon-vm-nightrun03.

The blue direction arrows in this row enable you to view earlier or later versions of this node and are configured as follows:

Arrows pointing left—Click once to display the next earlier version.
Arrows pointing right—Click once to display the next later version.

Alternatively, you can click the version number directly in each column. The historical comparison between the two versions that you select is displayed automatically.
One type of information change is color-coded in yellow and recorded on the page, indicating that information differs across selected separate nodes, attributes, or attribute items.

For certain attributes in each node, you can view a separate list of data that shows unique and common items particular to that node. For this example, you can click the links to show detailed information for each separate node for the following attributes:

Software Instances
Runtime Environments
Containing VM
Packages

For example, you can click the link in either node column for the Packages attribute. This example shows that node de-32-R8-2 has 4 packages that are unique and 307 packages that it has in common with node lon-vm-nightrun03. It also shows that node lon-vm-nightrun03 has 4 packages that are unique.

For any of the listed patches on either node, you can click the radio button next to it to select that particular patch. The historical comparison facility enables you to compare individual patches (or other attributes) across the two nodes that you have selected for comparison.

To compare individual attributes:

Click the radio button next to an individual patch for each of the two nodes.
Click Compare.
Click Compare again to return to the previous page.
Click the link to return to the summary view.

At any time, you can change the nodes that you are comparing by clicking Change Comparison at the bottom of the page.

Using this facility, you can compare any like-nodes in BMC Helix Discovery with each other, their individual attributes and individual items in selected attributes over any period of time.