Host node

A Host node represents a general purpose computer on the network; any physical or virtual computer system in your organization. A host is of a specific type, such as a server or a desktop which BMC Discovery gains high quality interactive access to. A host is not an IP-connected device, such as a switch or a router.

The attributes of a Host node contain stable information about the host, such as processor and memory details, its primary host name, OS information, whether it is virtual, and so forth. Hosts are considered inferred information because rules inside the reasoning engine are used to determine which hosts exist based on the DiscoveryAccess results obtained. Hosts will only be created for discovery targets that should be considered hosts, as opposed to switches, printers or other infrastructure.

Host node lifecycle

The following section describes the scenarios in which a Host node is created, updated or destroyed automatically.

Creation/update

In order to maintain the model of hosts in the environment, BMC Discovery identifies hosts using an internal weighting algorithm, see Uniquely Identifying a Host for more information. Hosts are identified by a number of criteria using this algorithm. The creation, update and removal of a Host node are based on these identities.

A Host node is created in the datastore when a new host is inferred from a successful discovery. A Host is only created when good quality access to the target computer has been established. Good quality access is necessary for the BMC Discovery internal system to establish that there is sufficient stable information available to identify a Host. Stable information is considered to be data such as hardware details, how many active interfaces there are, bios serial numbers and so forth.

A Host node is not created unless information is available from the getDeviceInfo, getHostInfo, and getMACAddresses methods.

For as long as BMC Discovery's host identification algorithm can determine that a particular discovery target corresponds to a particular Host node, the Host node is updated every time the target is scanned on any of its IP addresses. Once a Host node is created, BMC Discovery will update its attributes as the host changes over time, while still retaining the original Host node and key.

When a Host node is first created, BMC Discovery constructs a key attribute that uniquely identifies the host. The key is based on a combination of attribute values from the Host, but those attributes can change over time. As the host is rescanned, the Host node attributes that contributed to the key can all change, but the key itself will not be changed. If a Host node is destroyed and then the corresponding host is rescanned, a new Host node will be created. If the attribute values that were originally used to construct the key have not changed, the new Host node will be given the same key as the original one, but if any of the attributes have changed, the new Host node will have a different key to the old one.

Removal

Host node can be destroyed either manually or automatically.

To remove a host node manually, find the host, select it in the list and pick Destroy from the Actions list.

By default, a Host node will be automatically destroyed, if BOTH of the following circumstances are fulfilled:

  • No update has been made in ten days from any of the IP addresses known for this host.
  • No update has been made in the last seven scans on the IP address currently being scanned.

Thus, if a host is not successfully scanned, by default, the Host node representing it will remain in the model for at least 10 days. In this context, "seen" means anything other than no update. The table below shows the default removal criteria for the Host node.

Node Kind

Days

Scans

Host

10

7

These are the default settings for the number of days and number of scans. You can change these settings on the Model Maintenance page. See Configuring model maintenance settings for more information.


When a Host node is destroyed, its related nodes are destroyed too. That is, if a Host node is destroyed, all of its software instances, network interfaces, files, and HBAs are also destroyed.

When a node with attachments is destroyed, the attachments are not destroyed, and remain attached to the destroyed node. See Attachments for an introduction to attachments.
If a host node is destroyed from the datastore, all of its relationships are destroyed as well. For example, a host might have a relationship to a location. If the host is destroyed, the relationship to that location will also be destroyed. See How nodes are removed.

Uniquely Identifying a Host

There is no single identifying attribute that can be used reliably to identify hosts. BMC Discovery determines host identities using an internal host identification algorithm to select which existing Host node should be connected, if any, with the Directly Discovered Data from the current scan.

A Host node is only created or updated when BMC Discovery has enough information to determine that a suitable Host node does not already exist or that an existing Host node is the one to use. A host will not be created or updated unless BMC Discovery has working credentials to extract enough information from the host.

Once BMC Discovery has sufficient information on the scanned endpoint it searches in the datastore for candidate Host nodes to be updated. This is carried out using a series of search queries, for example:

  • Host previously updated via a scan from this endpoint.
  • Host with one of its IP addresses being the endpoint scanned.
  • Host with the same bios serial number as the scanned endpoint.

The Host nodes returned by these, and other searches, are candidates for being linked with the scanned Discovery Access node.

All the candidates are then ranked using the BMC Discovery algorithm based on the data on the candidate and the data currently retrieved from the endpoint. Each attribute on the host could be one of the following:

  • Confirmed - same attribute key, same value.
  • Changed - the value on the host for that attribute key is different from the value scanned.
  • Absent - the value is set on the candidate, but is no longer available in the scanned data.

For each attribute a score is set for confirmed, changed or absent values. These scores are then added together to build the ranking. The score for all the attributes are then added together.

Once all the candidates have been evaluated, Host nodes with a negative ranking are ignored, and the highest positive-ranked Host node will be chosen. If no Host nodes have a positive score, or if no candidates have been found, a new Host node is created. In all cases, the Host node is then updated with the new data.

Endpoint identity

BMC Discovery scans IP addresses, or endpoints. It is the job of the Host identification algorithm to match endpoints to Host nodes. When an endpoint is scanned, the host identification algorithm sometimes decides that the endpoint now corresponds to a different Host node to the previous scan of that endpoint. This can happen for three main reasons:

  1. IP addresses have been reassigned so the endpoint really does correspond to a different host.
  2. The endpoint still corresponds to the same host, but the host has changed so much since the previous scan that BMC Discovery cannot tell that it is the same one.
  3. The endpoint still corresponds to the same host, but BMC Discovery's access credentials have changed substantially, meaning the data appears very different. This can happen when switching between SNMP and login access, for example.

All three situations look the same from BMC Discovery's point of view — the discovered data is significantly different from the data previously retrieved from the endpoint. To facilitate understanding of these scenarios, BMC Discovery creates an EndpointIdentity relationship between the Host nodes. The Host view displays the relationship and allows comparison of the new and old Host nodes.

In all situations, BMC Discovery will ultimately resolve the condition. If the change is due to an IP address reassignment, the original Host can be found by scanning a different endpoint. If that happens, the Host is connected to the new endpoint and the EndpointIdentity relationship is removed. In other situations, the original Host node will age out according to the normal ageing rules.

Virtualization and Consolidation

BMC Discovery performs consolidation of virtual and partitioned hosts. When it does this, the model it constructs is as follows:

Virtual Hosts

Virtual Hosts are modeled so that the virtual host is related through the software instance to the physical host. For example:

  • VMware Virtual Machines
  • Solaris Containers 

Contained Hosts

Where a number of IP devices are discovered that are logical devices on hosts, they are modeled as shown in the diagram below. See Host node lifecycle.
For example, the following types of servers are treated in this manner:

  • Sun Enterprise 10000 - E10K
  • Sun Fire 12000 - F12K
  • Sun Fire 15000 - F15K
  • Sun Fire 20000 - F20K
  • Sun Fire 25000 - F25K 

Clustered Hosts

Where a number of collaborative hosts are discovered (they are seen as individual IP devices and there is no parent), they are consolidated into clusters which are modeled as Cluster nodes, see Cluster node lifecycle. For example, the following types of cluster are treated in this manner:

  • Microsoft Clusters
  • Veritas Cluster Servers

Host node attributes

The attributes and relationships of a Host node are described in the tables below. Where hidden attributes are included, they are described in the most relevant section. Not all attributes are discovered for every platform, see the Discovered attributes by platform page for information on this.

Fields that are displayed in the user interface but have no related attribute on a Host node, that is, they are inherited or populated by relationships, are also shown.

UI Name
Attribute Name and Type

Description

General Details

name string

The name that the host is known by, typically the same as hostname.

Not displayed in UI
hostname string

The name that the host is known by systems external to this host.

Not displayed in UI
key string

Globally unique key.

Short Name
short_name string
Short name.

Not displayed in UI
description string

Description of the host. Legacy attribute not currently used. Can be used by patterns if desired.

Not displayed in UI
url string

URL for information about the host. Legacy attribute not currently used. Can be used by patterns if desired.

Not displayed in UI
business_continuity_critical boolean

If true, the host is critical to operation of the business. Legacy attribute not currently used. Can be used by patterns if desired

Not displayed in UI
third_party_support boolean

If true, the host is supported by a third party. Legacy attribute not currently used. Can be used by patterns if desired

Not displayed in UI
synonyms list:string

Other names by which this host is known. Legacy attribute not currently used. Can be used by patterns if desired

Not displayed in UI
host_type string

Type such as 'UNIX Server', 'Windows Desktop', and so on. This attribute is deprecated, use type instead.

Type
type string

Type such as 'UNIX Server', 'Windows Desktop', and so on.

Hardware Vendor
vendor string

The hardware vendor, for example, Dell Computer Corporation.

Virtual
virtual boolean

Flag if the host is virtual.

Partition
partition boolean

Flag if the host is a partition.

Virtualization Class
vm_class_string_

Class of virtual machine.

E10K SSP Hostname
ssphostname string

The E10K SSP Hostname, the physical host for a Sun Microsystems "Blade" Servers. This is available on Sun Enterprise 10000 systems only.

SunFire Domain
sunfire_domain string

F15K SunFire domain. Common to all blades in a SunFire server. The attribute is set for all Host nodes which are members of the server.

Zonename
zonename string

The Solaris Zonename of this host and its container. Currently only Solaris 10 supports zonenames.

LDOM Name
ldom_name string

Solaris LDOM name.

LDOM Role
ldom_role string

Solaris LDOM role.

Power LPAR Name
lpar_name string

IBM Power LPAR Name.

Power LPAR Number
lpar_partition_number : int

IBM Power LPAR Number.

Product Model
product_model string

The model name publicized by the vendor. Only set when different from Model. 

Not displayed in UI
last_access_response string

Response from last attempt to access Host.

Not displayed in UI
no_response_count int

Number of no responses since last success.

Not displayed in UI
access_failure_count int

Number of access failures since last success.

Not displayed in UI
new_endpoint_identity_count int

Number of access where endpoint reports different device.

Identity

Local FQDN
local_fqdn string

The fully qualified domain name of the host.

DNS Domain
dns_domain string

The DNS domain to which the host belongs.

NIS/Windows Domain
domain string

The NIS/Windows domain to which the host belongs.

Windows Workgroup
workgroup string

The Windows workgroup to which this host belongs.

Operating System

OS
os string

The name and version of the Operating system. For example, Mandrake Linux release 9.1 (Bamboo) for i586.

OS Class
os_class string

Operating system class.

OS Type
os_type string

Operating system type. The name part of the os attribute. For example, Mandrake Linux.

OS Version
os_version string

Operating system version. The version part of the os attribute. For example, 9.1.

OS Edition
os_edition string

Operating system edition.

OS Architecture
os_arch string

Operating system architecture.

OS Update Level
os_level string

Operating system update level.

OS Build
os_build string

Operating system build information.

OS Vendor
os_vendor string

Operating system vendor.

Service Pack
service_pack int

Service Pack number. Windows only.

Kernel
kernel string

The version of the kernel. For example, on an AIX host, 5.3.

Patches and Packages

Package Count
package_count int

The number of packages.

Patch Count
patch_count int

The number of patches.

Attributes used internally to short circuit some processing

Not displayed in UI
__patch_checksum string

The patch checksum.

Not displayed in UI
__package_checksum string

The package checksum.

Host aging attributes

Not displayed in UI
age_count int

The number of consecutive successful (positive) or failed (negative) accesses, from any endpoint.

Not displayed in UI
last_update_success date

The time at which a scan was last successfully associated with this host.

The "last_update_success" for Hosts changed in BMC Discovery 11.0. In earlier versions it was formatted in this way:

Last Update Success
2016-09-17 14:17:40.62

In BMC Discovery 11.0 and later versions it is formatted in this way:

Last Update Success
2016-09-17 14:17:40.624471+00:00

Not displayed in UI
last_update_failure date

The time at which a scan associated with this host failed.

Hardware and Network

Model
model string

The model name of the hardware.

Serial Number
serial string

The serial number of the hardware.

UUID
uuid string

The universally unique identifier (UUID) of the host.

Unique Host Id
hostid string

Unique Host identification string.
When HP-UX partitions are scanned, the partition ID is determined and appended to the original hostid. This differentiates individual hosts in an HP-UX domain.

Logical RAM
logical_ram int

The amount of RAM (in MB) available on the host, as reported by OS.

Physical RAM
ram int

The amount of RAM (in MB) installed on the host.

Number of Processors
num_processors int

The number of physical processors on the host.

Processor Type
processor_type string

The type of processor used in the host. For example, Intel(R) Pentium(R) 4 CPU.

Processor Speed
processor_speed int

The speed of each processor in MHz.

Number of Logical Processors
num_logical_processors int

The number of logical processors available to the OS.

Cores per Processor
cores_per_processor int

The number of cores per physical processor available to the OS.

Threads per Processor Core
threads_per_core int

The number of threads per core in multi/hyper threaded processors available to the OS.

CPU Threading Enabled
cpu_threading_enabled boolean

Whether CPU hardware threading is enabled.

Number of Processor Types
num_processor_types int

The number of physical processor types.

All Processor Types
_all_processor_types list:string

List of all processor types.

All Processor Speeds
_all_processor_speeds list:int

List of all processor speeds.

Logical Processor Counts
_all_processor_logical_counts list:int

List of logical processor counts.

Physical Processor Counts
_all_processor_physical_counts list:int

List of physical processor counts.

Not displayed in UI
_all_threads_per_core list:int

List of threads per core counts.

Not displayed in UI
_all_cores_per_processor list:int

List of cores per processor counts.

Power Supply Status
psu_status list:string

Displays the status for each power supply. This can be either OK or Fail.

Attributes used only to facilitate search queries

Not displayed in UI
__all_ip_addrs list:string

BMC Discovery internal use only. Do not use. Internal attribute to aid searching Hosts by IP address.

Not displayed in UI
__all_dns_names list:string

BMC Discovery internal use only. Do not use. Internal attribute to aid searching Hosts by name.

Attributes used for grouping

_excluded_from_grouping boolean

BMC Discovery internal use only. Records that a node has been marked as excluded from automatic grouping. Do not use.

Attributes used for CMDB Sync

CDM Virtual System Type
cdm_virtual_system_type int

Attribute for populating the CDM BMC_ComputerSystem.VirtualSystemType attribute.

Last successful CMDB sync
last_cmdb_sync_success date

The time at which this Host was last successfully synchronized into the CMDB.

Last failed CMDB sync
last_cmdb_sync_failure date

The time at which an attempt to synchronize this Host into the CMDB failed.

CMDB sync duration
last_cmdb_sync_duration float

The time in seconds spent performing the last CMDB synchronization of this Host.

CMDB CI count
last_cmdb_sync_ci_count int

The number of CIs corresponding to this Host at the last CMDB synchronization.

CMDB Relationship count
last_cmdb_sync_rel_count int

The number of relationships between CIs corresponding to this Host at the last CMDB synchronization.

Host node relationships

The relationships on a Host node are as described in the following table:

 

UI name

Relationship

Description

Containing AutomaticGroup

Host:
ContainedItem:
Containment:
Container:
AutomaticGroup

Owning AutomaticGroup.

Containing Group

Host:
ContainedItem:
Containment:
Container:
Group

Owning Group.

Location

Host:
ElementInLocation:
Location:
Location:
Location

Location of this Host.

Hosted Applications

Host:
Host:
HostedSoftware:
AggregateSoftware:
BusinessApplicationInstance

Business Application Instances running on this Host.

Software Instances

Host:
Host:
HostedSoftware:
RunningSoftware:
SoftwareInstance

Software Instances running on this Host.

Aggregate Software Instances

Host:
Host:
HostedSoftware:
AggregateSoftware:
SoftwareInstance

Aggregate Software Instances running on this Host.

Runtime Environments

Host:
Host:
HostedSoftware:
RunningSoftware:
RuntimeEnvironment

Runtime Environments on this Host.

Host Container

Host:
ContainedHost:
HostContainment:
HostContainer:
HostContainer

Host container of which this is a member.

Cluster

Host:
ContainedHost:
HostContainment:
HostContainer:
Cluster

Cluster of which this is a member.

Containing VM

Host:
ContainedHost:
HostContainment:
HostContainer:
VirtualMachine

Software container for this virtual Host.

Network Interfaces

Host:
DeviceWithInterface:
DeviceInterface:
InterfaceOfDevice:
NetworkInterface

Network interfaces of this Host.

IPv4 Addresses

Host:
DeviceWithAddress:
DeviceAddress:
IPv4Address:
IPAddress

IPv4 addresses of this Host.

IPv6 Addresses

Host:
DeviceWithAddress:
DeviceAddress:
IPv6Address:
IPAddress

IPv6 addresses of this Host.

Fibre Channel HBAs

Host:
DeviceWithInterface:
DeviceInterface:
InterfaceOfDevice:
FibreChannelHBA

Fibre Channel HBAs of this Host.

Files

Host:
Host:
HostedFile:
HostedFile:
File

Files on this Host.

Device Info

Host:
InferredElement:
Inference:
Primary:
DeviceInfo

DeviceInfo of this Host.

Host Info

Host:
InferredElement:
Inference:
Primary:
HostInfo

HostInfo of this Host.

Discovery Access

Host:
InferredElement:
Inference:
Associate:
DiscoveryAccess

DiscoveryAccess for this Host.

Patches

Host:
Host:
HostedSoftware:
InstalledSoftware:
Patch

Patches on this Host.

Not displayed in UI

Host:
InferredElement:
Inference:
Contributor:
DiscoveredPatches

Patches contributing to this Host's attributes.

Packages

Host:
Host:
HostedSoftware:
InstalledSoftware:
Package

Packages on this Host.

Not displayed in UI

Host:
InferredElement:
Inference:
Contributor:
DiscoveredPackages

Packages contributing to this Host's attributes.

File System

Host:
Mounter:
FileSystemMount:
MountedFileSystem:
FileSystem

FileSystem of this Host.

Disk Drives

Host:
Container:
Containment:
ContainedDrive:
DiskDrive

DiskDrives contained in this Host.

Disk Drives

Host:
Consumer:
StorageUse:
Provider:
DiskDrive

DiskDrives used by this Host.

Storage Volumes

Host:
Consumer:
StorageUse:
Provider:
StorageVolume

Storage Volumes used by this Host.

Endpoint Used To Be Identified As

Host:
Next:
EndpointIdentity:
Previous:
Host

Previous Host Identity.

Endpoint Now Identified As

Host:
Previous:
EndpointIdentity:
Next:
Host

Next Host Identity.

Endpoint Used To Be Identified As

Host:
Next:
EndpointIdentity:
Previous:
NetworkDevice

Previous Network Device Identity.

Endpoint Now Identified As

Host:
Previous:
EndpointIdentity:
Next:
NetworkDevice

Next Network Device Identity.

Endpoint Used To Be Identified As

Host:
Next:
EndpointIdentity:
Previous:
Mainframe

Previous Mainframe Identity.

Endpoint Now Identified As

Host:
Previous:
EndpointIdentity:
Next:
Mainframe

Next Mainframe Identity.

Endpoint Used To Be Identified As

Host:
Next:
EndpointIdentity:
Previous:
Printer

Previous Printer Identity.

Endpoint Now Identified As

Host:
Previous:
EndpointIdentity:
Next:
Printer

Next Printer Identity.

Endpoint Used To Be Identified As

Host:
Next:
EndpointIdentity:
Previous:
SNMPManagedDevice

Previous SNMP Managed Device Identity.

Endpoint Used To Be Identified As

Host:
Next:
EndpointIdentity:
Previous:
ManagementController

Previous Management Controller Identity.

Endpoint Now Identified As

Host:
Previous:
EndpointIdentity:
Next:
ManagementController

Next Management Controller Identity.

Endpoint Now Identified As

Host:
Previous:
EndpointIdentity:
Next:
SNMPManagedDevice

Next SNMP Managed Device Identity.

Endpoint Used To Be Identified As

Host:
Next:
EndpointIdentity:
Previous:
StorageDevice

Previous Storage Device Identity.

Endpoint Now Identified As

Host:
Previous:
EndpointIdentity:
Next:
StorageDevice

Next Storage Device Identity.

Chosen Endpoint

Host:
Device:
ChosenEndpoint:
Endpoint:
Endpoint

Endpoint used to discover this Host.

Hardware Reference Data

Host:
Hardware:
ReferenceData:
ReferenceData:
HardwareReferenceData

Hardware Reference data corresponding to this Host.

Hardware Support Details

Host:
ElementWithDetail:
SupportDetail:
HardwareDetail:
SupportDetail

Hardware Support Detail related to this Host.

OS Support Details

Host:
ElementWithDetail:
SupportDetail:
OSDetail:
SupportDetail

OS Support Detail related to this Host.

Details

Host:
ElementWithDetail:
Detail:
Detail:
Detail

Details of this Host.

Collections

Host:
Member:
Collection:
Collection:
Collection

A collection which this Host is a member of.

Communicating With

Host:
Host:
ObservedCommunication:
Host:
Host

Other Hosts that this Host is communicating with. Only created when automatic grouping is enabled.

Managed by Software Instance

Host:
ManagedElement:
Management:
Manager:
SoftwareInstance

Software Instances that manage this Host.

Managed by SNMP Managed Device

Host:
ManagedElement:
Management:
Manager:
SNMPManagedDevice

SNMP Managed Device that manages this Host.

Managed by Management Controller

Host:
ManagedElement:
Management:
Manager:
ManagementController

Management Controller that manages this Host.

Discovery Conditions

Host:
ElementWithCondition:
DiscoveryCondition:
DiscoveryCondition:
DiscoveryCondition

Discovery conditions to which this element pertains.

Discovery Access Failure

Host:
InferredElement:
AccessFailure:
DiscoveryAccess:
DiscoveryAccess

The failed access for an endpoint.

Discovery Access Optimization

Host:
InferredElement:
AccessOptimization:
DiscoveryAccess:
DiscoveryAccess

The optimized access for an endpoint.

Load Balancer

Host:
ServiceHost:
SoftwareService:
Service:
LoadBalancerMember

Load balancer member.

Not displayed in UI

Host:
AttachmentContainer:
Attachment:
Attachment:
Attachment

A file attached to this element.

Status

Host:
ElementInCategory:
ElementCategory:
Category:
LifecycleStatus

The lifecycle status of this element.

Recovery Time

Host:
ElementInCategory:
ElementCategory:
Category:
RecoveryTime

The recovery time specified for this element.

Family

Host:
ElementInCategory:
ElementCategory:
Category:
Family

Family of this element.

Organizational Unit

Host:
OwnedItem:
Ownership:
Owner:
OrganisationalUnit

The Organizational Unit that this element belongs to.

Location

Host:
ElementInLocation:
Location:
Location:
Location

Location of this element.

Support Manager

Host:
OwnedItem:
Ownership:
SupportOwner:
Person

The person responsible for the support of this element.

Business Owner

Host:
OwnedItem:
Ownership:
BusinessOwner:
Person

The person responsible for this element from a business perspective.

IT Owner

Host:
OwnedItem:
Ownership:
ITOwner:
Person

The person responsible for this element from an IT perspective.

Clustered Software Instances

Host:
Host:
HostedSoftware:
ClusteredSoftware:
SoftwareInstance

Clustered Software Instances running on this Host.

Candidate Software Instances

Host:
Host:
HostedSoftware:
RunningSoftware:
CandidateSoftwareInstance

Candidate Software Instances running on this Host.

Unassigned Connections

Host:
Host:
HostedSoftware:
RunningSoftware:
UnassignedConnections

Unassigned Connections observed on this Host.

Cluster Member

Host:
ServiceHost:
SoftwareService:
Service:
ClusterMember

Cluster member that this host represents.

Manages Storage Systems

Host:
Manager:
Management:
ManagedElement:
StorageSystem

Storage systems on this device.

Processor Information

Host:
Host:
Detail:
Hardware:
ProcessorInfo

Processor information.


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