When you baseline a data center, one of the first tasks is to subdivide it into small groups of hosts. BMC Atrium Discovery does this automatically for all discovered hosts at the end of each scan.
Automatic grouping is intended as a baselining tool for use at the scale of 100 to 500 hosts. At larger scale, the usefulness and usability of the visualizations is diminished.
How automatic grouping works
There are three types of group created automatically:
- Group around a host
- Clients of a host
- Hosts with no relevant communication
When a host is involved in automatic grouping, the
Host:Host:ObservedCommunication:Host:Host relationship (Communicating With) is displayed on the host page.
An additional group type can be created manually by excluding hosts from automatic grouping. These are placed into a group called "Hosts Excluded from Automatic Grouping". This is described in Excluding hosts from automatic grouping below.
You can enable or disable automatic grouping in the Discovery configuration page.
These groups are created in the following way after each scan:
- Groups hosts which communicate with one another — These are called Group around hostname.
Any two hosts which are seen to communicate are called neighbors. When a pair of hosts are considered, the connection between them is ranked. A higher rank increases the probability of them being grouped. The ranking is calculated according to the proportion of their total neighbors that they share. Where more neighbors are shared, the ranking is higher, and the hosts are more likely to be grouped. This is used to reduce the chances of clients of shared infrastructure being grouped on the basis of those connections.
- Groups hosts which are clients of a particular set of servers — These are called Clients of host.
- Hosts with no observed communication — These are grouped in the "Hosts with no relevant communication" group. Further hosts, that communicate only with hosts that have been excluded from grouping, are also placed in this group.
Host Groups are stored as AutomaticGroup nodes in the datastore.
To see how your hosts are grouped
There are several ways to view automatic grouping.
Automatic grouping channel
The automatic grouping channel shows a summary of the current grouping results:
Click any of the icons to view a visualization. The top row shows:
- The overview. This is a visualization that shows all automatic groups and how they communicate with each other.
- No relevant communication. A visualization of the group containing hosts that have either no communication at all or are communicating only with excluded hosts.
- Excluded hosts. Hosts that have been excluded from the automatic grouping process (see below).
The following line shows up to five of the most highly connected groups; that is, those that are communicating with the most other groups. The final line shows up to five of the largest unconnected groups, self-contained groups that do not communicate outside themselves at all.
- Select the Infrastructure section from the Primary Navigation bar.
- From the Infrastructure page, click the Explore tab on the Dynamic Secondary Navigation bar.
To interact with the visualizations
The controls (Zoom & Pan, Layout, Printing & Export) operate in the same way as Dependency Visualizations. The usual menu options also appear when clicking on a node (View Details, Manual Groups..., Hide, and Unhide Neighbors, although there is no Re-Center option) and clicking on the background (Unhide All).
Right clicking on an Automatic Group displays a pop-up menu with the usual four menu options listed above and an additional option, Open, which shows a more detailed visualization of the clicked group. This is a drill-down option, and shows the hosts that compose the automatic group, how they are communicating, and the other automatic groups they are communicating with.
Host nodes show an additional menu option that controls whether the host is included in automatic grouping. The menu item shows as either Exclude From Automatic Grouping or Include In Automatic Grouping, depending on the current state of the node. See below for more information about this.
The Automatic Grouping palette block on the left has a link to return to the overview visualization from any detail visualization.
To observe host communication
To see details of why two hosts are communicating, right-click the edge between them, and choose the only menu option, Show Communication Details.
A report of all directly discovered network connections that contributed to the observed communication link between the hosts is displayed.
To exclude hosts from automatic grouping
Some hosts in your estate might be super-connected which means they are connected to many, perhaps all other hosts in the estate. This might be interesting information. However, once noted, it can be useful to remove these hosts from the grouping algorithm in order to focus on the the other hosts. BMC Atrium Discovery lets you do this by marking such hosts to be excluded from automatic grouping by using the Exclude From Automatic Grouping option.
After a host is marked as excluded from automatic grouping, it is displayed differently to make this obvious: it is grayed out slightly, and has an excluded icon overlayed on it.
To actually see the results of excluding the host, the grouping algorithm must be re-run. Several hosts can be marked as excluded from automatic grouping before re-running the algorithm. To re-run the algorithm, click Update that appears in the Automatic Grouping palette block on the left. Regrouping then occurs and the overview visualization is redisplayed.
Hosts that are excluded from automatic grouping appear in a special group, labeled Hosts Excluded From Automatic Grouping. This is displayed on the overview visualization in a similar way to hosts with no observed communication.
Drilling into this group shows all the hosts in the group, how they are communicating, and the other groups with which they are communicating, as before. However, hosts in the other groups with which the excluded hosts are communicating no longer show a communicating relationship to the excluded host, and the groups are calculated without regard for the communications to and from the excluded hosts. This also means that hosts that are communicating only with excluded hosts are moved into the Hosts with no relevant communication group.
Hosts can be included again by right-clicking an excluded host and choosing Include In Automatic Grouping.