Getting the Most from Your Scan
This section includes some pre-discovery tips and preparation that will make your network and device discovery scan more effective.
Discovery Basics. Understand the basic elements needed for discovering your network and devices.
Goals of discovery:
- Find connected devices on your network.
- Apply credentials (and see which ones work) to enable rich information flow.
- Scan your network and return a list/map that represents your network or segment that you can decide promote to My Network or hide and defer from monitoring.
Tip: After you add monitoring to a device from Discovered Network view, you then manage it (clone, delete, curate its monitoring scheme, and so on) from My Network view. For example, monitored devices can only be deleted from WhatsUp Gold using the device management actions available in My Network.
Effectiveness and richness of information returned from network and device discovery is dependent on:
- Credential list.
Credentials associated with the scan profile enable the Discovery Service to query management objects, platform attributes, and configurations on the device.
- Connectivity to networks and devices.
- For OS/virtual/application layer information, ensure devices are powered on.
- Ensure firewalls can be traversed (if you want to include a device for monitoring that is on the other side of the DMZ).
- Connectivity to management services.
WhatsUp Gold gathers performance metrics from platform and proprietary MIBs using SNMP, from devices running Windows using WMI, from Linux and UNIX machines using SNMP and SSH, and VMware-specific host and VM metrics using VMware credentials to query vCenter, Windows credentials for accessing Hyper-V hosts, and so on. When connectivity to management services such as these is available by way of open network routes, ports, and appropriate credentials, the Discovery Service can make a more complete set of default monitors available to the discovered device.
- Freshness of scan and of results.
If your network composition changes frequently, you can apply periodic scans to ensure freshness of information.
Note: As it scans, WhatsUp Gold Discovery must adapt to twist and turns in your site's network topology and overall configuration. Connectivity to management services and associating the proper credentials list with the scan profile are key to an effective scan that returns rich information.
Ensure Devices Have SNMP/WMI Capability. SNMP/WMI needs to be configured/enabled.
Devices should be configured to respond to SNMP requests whenever possible. Alternatively, at discovery time, WhatsUp Gold can also gather information about Windows devices using WMI.
Important: You can add an SNMP agent (Windows service) from the Turn Windows Feature On or Off dialog for your current Windows device. In most cases, this Windows feature will already be enabled.
Note: In most cases, the information available using WMI is also available using SNMP. Where SNMP requests are more efficient than WMI requests, Ipswitch recommends using SNMP for discovery.
Tip: For the best discovery results, configure all of the credentials used by devices on your network prior to initiating a discovery scan.
After WhatsUp Gold discovers a device, it uses SNMP MIB or WMI (Windows Management Instrumentation) data recorded on that device to gather any appropriate device properties and configuration information. The information it collects enables WhatsUp Gold to identify the device and includes but is not limited to:
- Device manufacturer and model.
- Installed hardware and software components such as fans, CPUs, hard disks, and the version and type of operating system.
- Specific services (such as HTTP or DNS).
Ensure Devices Can Be Reached. Devices need to be reachable and powered on for rich discovery information.
WhatsUp Gold attempts to discover devices on your network using ping (ICMP) and by scanning for open TCP ports. Check to see if network devices respond to one or both of these request types before beginning discovery.
If a firewall exists between WhatsUp Gold and the devices to be discovered or if the Windows firewall is enabled on the computer where WhatsUp Gold is installed, make sure the appropriate ports are open to allow WhatsUp Gold to communicate via SNMP and WMI.
Discover Virtual Hosts/VMs from the Top...Down. Specify servers (like vCenter) and hypervisors in your discovery scan.
When you discover virtual resources, include IP addresses of vCenters or hypervisors in your scan specification rather than individual VMs. WhatsUp Gold becomes aware of individual virtual machines through managing elements (such as vCenters, Hyper-V hosts, and standalone hypervisors) as part of the discovery process.
When including virtual environments in your discovery scan, follow these guidelines:
- Discover management services first (such as VMware vCenter).
- In unmanaged environments (no vCenter and one or more ‘stand-alone’ hypervisors), you can discover individual hypervisors.
- After the discovery scan completes, apply monitoring to all nodes belonging to the virtual environments (select each node and click the Start/Update Monitoring button) for each of the vCenter, hypervisors, and virtual machines.
Important: To ensure that VMware vCenter, cluster, datacenter, hypervisor, and virtual machine relationships are recognized by WhatsUp Gold and later reflected on the Network Map, you must apply/update monitoring (Start/Update Monitoring) to both the managing elements, the hypervisors, and the associated the virtual machines after discovery.
Prerequisites
Before you invoke a discovery scan on your virtual environment, check that you have these:
VMware. Valid VMware credentials are used. VMware Tools are also required.
- VMware Tools must be installed on each virtual machine you deploy. Otherwise, the virtual device will not be discovered during the VMware scan.
- For detailed statistics and system information (for example, VMware Datastore IOPS monitor), add VMware credentials to VMware VMs as well as for the vCenter server.
Tip: If you delete a vCenter from WhatsUp Gold, applicable host/guest relationships will not be recognized. In order to retain these relationships, delete the host as well, then rediscover the host and add it back into WhatsUp Gold.
Hyper-V. Hyper-V devices are discovered when valid Windows credentials are used. Groups and users for passing WMI management objects must be in place. Host OS Application firewalls must align with default Hyper-V firewall rules.
Configure Account Access for Passing WMI
The appropriate Windows users or groups must be configured to allow access to the following WMI namespaces:
- root\cimv2. Allows for discovery of any windows device using WMI.
- root\virtualization\v2. Allows for discovery of Hyper-V host (2012 server, 2012 R2 server, and Windows 8).
- \root\default. Allows for discovery of any additional registry information available.
Align Host OS for Hyper-V/WMI Firewall Rules
The following firewall exceptions must be created:
- Port 135 must be opened for data collection using WMI.
- TCP/UDP traffic must be allowed on ports 1024-65535 or monitored objects using WMI will not be accessible.
WMI communications use a random port between 1024 and 65535 per Microsoft Windows specifications. The actual port used is determined by the remote machine. The port number range is based on the operating system being queried. The administrator can reduce or increase the range in most Windows operating systems.
Check Order of Credentials in the Discovery Scan
WhatsUp Gold attempts discovery using Windows credentials in priority order. The first credential used that is allowed any WMI access is selected. However, if that credential does not have access to each of the required namespaces discussed previously, Windows is successfully detected, but other device details which require additional namespace access fail. The result is the target device is discovered as a Windows device, but is not recognized as a Hyper-V Host.
Note: Procedures for configuring conditions for successful Hyper-V device discover may vary depending on core versus full installation as well as the operating system on which the configuration is being performed.
Discover VMware Environments
When you run a discovery scan, it is best to configure your scan to learn about VMware hypervisors and virtual machines through management services (such as VMware vCenter). In unmanaged virtual environments with stand-alone hypervisors (with just VMware ESXi, for example), you can discover hypervisors individually.
When hosts are managed by vCenter.
Discovering your virtual resources by way of vCenter is the preferred approach.
Guidelines:
- Provide the IP address of the vCenter at discovery scan time.
- Your Credentials Library (SETTINGS menu > Libraries > Credentials Library) must include the WhatsUp Gold VMware credentials for the vCenter.
- (Preferred) include VMware Credentials in WhatsUp Gold for each ESXi host (if they differ from the vCenter credentials). This is best practice, but some host/guest metrics are available through vCenter without them (that is, using only VMware credentials you provided for vCenter).
Discover and add monitoring to a vCenter and its managed elements
- From the IP Address Scan window (DISCOVER menu > New Scan), input the IP address of one or more vCenters. (You can unselect the Gateway IP and Local Subnet checkboxes.)
- In the Settings tab of the IP Address Scan window, click the Checkbox in Advanced Settings > Data Collection > Expand scan to any virtualization environments.
- In the Credentials tab of the IP Address Scan window, include the appropriate VMware credential, and click Run to begin the scan.
(Including the VMware credential for vCenter enables WhatsUp Gold to identify the device as a virtual host and learn about its managed hosts and their guest VMs)
Nodes (discovered devices) display on Discovery Map. - After the scan completes, select the VMware vCenter and discovered virtual machine nodes, and click the Start Monitoring button to add them to My Network Map with their associated default monitors.
Lines of association show relationship between hosts and virtual machines and hosts to their vCenter. - After a few minutes, check the virtual monitoring dashboard (ANALYZE menu > Dashboards > Virtual Monitoring) to see data gathered from monitors of newly discovered virtual devices.
Tip: If you delete a monitored vCenter from the WhatsUp Gold Network Map, the existing host/guest relationships between its managed virtual hosts and virtual machines will no longer be obvious to WhatsUp Gold. This can also impact the continuity of monitoring and logging. To retain continuity of information and host/guest relationships with WhatsUp Gold after a vCenter deletion, delete each virtual host, re-discover, and from the Discovered Devices Map, use Update Monitoring button to restore these relationships.
When hosts/hypervisors (ESX/ESXi) are run standalone (unmanaged).
For this scenario, your Credentials Library (SETTINGS menu > Libraries > Credentials Library) must include the WhatsUp Gold VMware credential for the VMware host you want to discover.
Discover and add monitoring to stand-alone ESX/ESXi hosts
- From the IP Address Scan window (DISCOVER menu > New Scan), input the IP address of one or more VMware ESX or ESXi hosts. (You can unselect the Gateway IP and Local Subnet checkboxes.)
- In the Settings tab of the IP Address Scan window, click the checkbox in Advanced Settings > Data Collection > Expand scan to any virtualization environments.
- In the Credentials tab of the IP Address Scan window, include the appropriate VMware credential(s) in your network scan. (Including the VMware credential to the hypervisor enables WhatsUp Gold to identify the device as a virtual host and query it for virtual machine information).
Network nodes (discovered devices) display on Discovery Map and the discovery scan completes. - Select each discovered hypervisor and virtual machine and click the Start Monitoring button to add them to My Network Map with default monitors.
Lines of association show relationship between hosts and virtual machines. - After a few minutes, check the virtual monitoring dashboard (ANALYZE menu > Dashboards > Virtual Monitoring) to see data gathered from monitors of newly discovered virtual devices.
Discover Hyper-V Environments
Specify DNS hostname or IP address for Hyper-V hosts when discovering Hyper-V environments.
For this scenario, your Credentials Library (SETTINGS menu > Libraries > Credentials Library) must include the WhatsUp Gold Hyper-V credential for the Hyper-V host you want to discover.
Discover and add monitoring to Hyper-V hosts and associated virtual machines
- From the IP Address Scan window (DISCOVER menu > New Scan), input the IP address of one or more Hyper-V hosts. (You can unselect the Gateway IP and Local Subnet checkboxes.)
- In the Settings tab of the IP Address Scan window, click the checkbox in Advanced Settings > Data Collection > Expand scan to any virtualization environments.
- In the Credentials tab of the IP Address Scan window, include the appropriate Hyper-V credential(s) in your network scan. (Including the Hyper-V credential to the hypervisor/host enables WhatsUp Gold to identify the device as a virtual host and query it for virtual machine information).
Network nodes (discovered devices) display on Discovery Map and the discovery scan completes. - Select each discovered hypervisor and virtual machine and click the Start Monitoring button to add them to My Network Map with default monitors.
Lines of association show relationship between hosts and virtual machines. - After a few minutes, check the virtual monitoring dashboard (ANALYZE menu > Dashboards > Virtual Monitoring) to see data gathered from monitors of newly discovered virtual devices.
Tip: In addition to being a powerful tool that enables you to discover, query, and assign monitors to your connected-devices, regular scans help keep the picture of your network current. Seeded discovery scans can shine light in dark corners, finding seldom used, forgotten, misconfigured, or even rogue devices.
|
See Also |