Monitor and manage your deployment

XenServer provides detailed monitoring of performance metrics. These metrics include CPU, memory, disk, network, C-state/P-state information, and storage. Where appropriate, these metrics are available on a per host and a per VM basis. These metrics are available directly, or can be accessed and viewed graphically in XenCenter or other third-party applications.

XenServer also provides system and performance alerts. Alerts are notifications that occur in response to selected system events. These notifications also occur when one of the following values goes over a specified threshold on a managed host, VM, or storage repository: CPU usage, network usage, memory usage, control domain memory usage, storage throughput, or VM disk usage. You can configure the alerts by using the xe CLI or by using XenCenter. To create notifications based on any of the available Host or VM performance metrics see Performance alerts.

Monitor XenServer performance

Customers can monitor the performance of their XenServer hosts and Virtual Machines (VMs) using the metrics exposed through Round Robin Databases (RRDs). These metrics can be queried over HTTP or through the RRD2CSV tool. In addition, XenCenter uses this data to produce system performance graphs. For more information, see Analyze and visualize metrics.

The following tables list all of the available host and VM metrics.

Notes:

• Latency over a period is defined as the average latency of operations during that period.
• The availability and utility of certain metrics are SR and CPU dependent.

Available host metrics

Available VM metrics

Note:

The value of <XenCenter-pif-name> can be any of the following:

• NIC <pif> - if <pif> contains pif_eth#, where ## is 0–9
• <pif> - if <pif> contains pif_eth#.## or pif_xenbr## or pif_bond##
• <Internal> Network <pif> - if <pif> contains pif_xapi##, (note that <Internal> appears as is)
• TAP <tap> - if <pif> contains pif_tap##
• xapi Loopback - if <pif> contains pif_lo

Analyze and visualize metrics

The Performance tab in XenCenter provides real time monitoring of performance statistics across resource pools in addition to graphical trending of virtual and physical machine performance. Graphs showing CPU, memory, network, and disk I/O are included on the Performance tab by default. You can add more metrics, change the appearance of the existing graphs or create extra ones. For more information, see Configuring metrics in the following section.

• You can view up to 12 months of performance data and zoom in to take a closer look at activity spikes.

• XenCenter can generate performance alerts when CPU, memory, network I/O, storage I/O, or disk I/O usage exceed a specified threshold on a host, VM, or SR. For more information, see Alerts in the following section.

Note:

Install the XenServer VM Tools to see full VM performance data.

Configure performance graphs

To add a graph:

1. On the Performance tab, click Actions and then New Graph. The New Graph dialog box is displayed.

2. In the Name field, enter a name for the graph.

3. From the list of Datasources, select the check boxes for the datasources you want to include in the graph.

4. Click Save.

To edit an existing graph:

1. Navigate to the Performance tab, and select the graph that you would like to modify.

2. Right-click on the graph and select Actions, or click the Actions button. Then select Edit Graph.

3. On the graph details window, make the necessary changes, and click OK.

Configure the graph type

Data on the performance graphs can be displayed as lines or as areas. To change the graph type:

1. On the Tools menu, click Options and select Graphs.

2. To view performance data as a line graph, click the Line graph option.

3. To view performance data as an area graph, click the Area graph option.

4. Click OK to save your changes.

Comprehensive details for configuring and viewing XenCenter performance graphs can be found in the XenCenter documentation in the section Monitoring System Performance.

Configure metrics

Note:

C-states and P-states are power management features of some processors. The range of states available depends on the physical capabilities of the host, as well power management configuration.

Both host and VM commands return the following:

• A full description of the data source

• The units applied to the metric

• The range of possible values that may be used

For example:

    name_label: cpu0-C1
    name_description: Proportion of time CPU 0 spent in C-state 1
    enabled: true
    standard: true
    min: 0.000
    max: 1.000
    units: Percent
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Enable a specific metric

Most metrics are enabled and collected by default, to enable those metrics that are not, enter the following:

xe host-data-source-record data-source=metric name host=hostname
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Disable a specific metric

You might not want to collect certain metrics regularly. To disable a previously enabled metric, enter the following:

xe host-data-source-forget data-source=metric name host=hostname
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Display a list of currently enabled host metrics

To list the host metrics currently being collected, enter the following:

xe host-data-source-list host=hostname
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Display a list of currently enabled VM metrics

To host the VM metrics currently being collected, enter the following:

xe vm-data-source-list vm=vm_name
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Use RRDs

XenServer uses RRDs to store performance metrics. These RRDs consist of multiple Round Robin Archives (RRAs) in a fixed size database.

Each archive in the database samples its particular metric on a specified granularity:

• Every 5 seconds for 10 minutes
• Every minute for the past two hours
• Every hour for the past week
• Every day for the past year

The sampling that takes place every five seconds records actual data points, however the following RRAs use Consolidation Functions instead. The consolidation functions supported by XenServer are:

• AVERAGE
• MIN
• MAX

RRDs exist for individual VMs (including dom0) and the XenServer host. VM RRDs are stored on the host on which they run, or the pool coordinator when not running. Therefore the location of a VM must be known to retrieve the associated performance data.

For detailed information on how to use XenServer RRDs, see the XenServer Software Development Kit Guide.

Analyze RRDs using HTTP

You can download RRDs over HTTP from the XenServer host specified using the HTTP handler registered at /host_rrd or /vm_rrd. Both addresses require authentication either by HTTP authentication, or by providing a valid management API session references as a query argument. For example:

Download a Host RRD.

wget http://server/host_rrd?session_id=OpaqueRef:SESSION HANDLE>
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Download a VM RRD.

wget http://server/vm_rrd?session_id=OpaqueRef:SESSION HANDLE>&uuid=VM UUID>
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Both of these calls download XML in a format that can be parsed directly.

Analyze RRDs using rrd2csv

In addition to viewing performance metrics in XenCenter, the rrd2csv tool logs RRDs to Comma Separated Value (CSV) format. Man and help pages are provided. To display the rrd2csv tool man or help pages, run the following command:

man rrd2csv
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Or

rrd2csv --help
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Note:

Where multiple options are used, supply them individually. For example: to return both the UUID and the name-label associated with a VM or a host, call rrd2csv as shown below:

rrd2csv -u -n

The UUID returned is unique and suitable as a primary key, however the name-label of an entity might not necessarily be unique.

The man page (rrd2csv --help) is the definitive help text of the tool.

Alerts

You can configure XenServer to generate alerts based on any of the available host or VM metrics. In addition, XenServer provides preconfigured alerts that trigger when hosts undergo certain conditions and states. You can view these alerts using XenCenter or the xe CLI.

View alerts using XenCenter

You can view different types of alerts in XenCenter by clicking Notifications and then Alerts. The Alerts view displays various types of alerts, including performance alerts, system alerts, software update alerts, license alerts, and VM anti-affinity group alerts. For more information, see Alerts.

Performance alerts

Performance alerts can be generated when one of the following values exceeds a specified threshold on a managed host, VM, or storage repository (SR): CPU usage, network usage, memory usage, control domain memory usage, storage throughput, or VM disk usage.

By default, the alert repeat interval is set to 60 minutes, it can be modified if necessary. Alerts are displayed on the Alerts page in the Notifications area in XenCenter. You can also configure XenCenter to send an email for any specified performance alerts along with other serious system alerts.

Any customized alerts that are configured using the xe CLI are also displayed on the Alerts page in XenCenter.

Each alert has a corresponding priority/severity level. You can modify these levels and optionally choose to receive an email when the alert is triggered. The default alert priority/severity is set at 3.

Configure performance alerts

1. In the Resources pane, select the relevant host, VM, or SR, then click the General tab and then Properties.

2. Select the Alerts tab. The following table summarizes which alerts are available for hosts, VMs, or SRs:

   Alert name	Host	VM	SR	Description
   Generate CPU usage alerts	X	X		Set the CPU usage and time threshold that trigger the alert.
   Generate control domain CPU usage alerts	X			Set the control domain CPU usage and time threshold that trigger the alert.
   Generate memory usage alerts	X			Set the memory usage and time threshold that trigger the alert.
   Generate control domain memory usage alerts	X			Set the control domain memory usage and time threshold that trigger the alert.
   Generate control domain free memory alerts	X			Set the control domain free memory and time threshold that trigger the alert.
   Generate disk usage alerts		X		Set the disk usage and time threshold trigger the alert.
   Generate storage throughput alerts			X	Set the storage throughput and time threshold that trigger the alert. Note: Physical Block Devices (PBD) represent the interface between a specific XenServer host and an attached SR. When the total read/write SR throughput activity on a PBD exceeds the threshold you have specified, alerts are generated on the host connected to the PBD. Unlike other XenServer host alerts, this alert must be configured on the SR.
   Generate network usage alerts	X	X		Set the network usage and time threshold that trigger the alert.

   To change the alert repeat interval, enter the number of minutes in the Alert repeat interval box. When an alert threshold has been reached and an alert generated, another alert is not generated until after the alert repeat interval has elapsed.

3. Click OK to save your changes.

For comprehensive details on how to view, filter and configure severities for performance alerts, see Configuring Performance Alerts in the XenCenter documentation.

System alerts

The following table displays the system events/conditions that trigger an alert to be displayed on the Alerts page in XenCenter.

Software update alerts

• XenCenter old: XenServer expects a newer version but can still connect to the current version
• XenCenter out of date: XenCenter is too old to connect to XenServer
• XenServer out of date: XenServer is an old version that the current XenCenter cannot connect to
• License expired alert: XenServer license has expired
• Missing IQN alert: XenServer uses iSCSI storage but the host IQN is blank
• Duplicate IQN alert: XenServer uses iSCSI storage, and there are duplicate host IQNs

Configure performance alerts by using the xe CLI

Note:

Triggers for alerts are checked at a minimum interval of five minutes. This interval avoids placing excessive load on the system to check for these conditions and reporting of false positives. Setting an alert repeat interval smaller than five minutes results in the alerts still being generated at the five minute minimum interval.

The performance monitoring perfmon tool runs once every five minutes and requests updates from XenServer which are averages over one minute. These defaults can be changed in /etc/sysconfig/perfmon.

The perfmon tool reads updates every five minutes of performance variables running on the same host. These variables are separated into one group relating to the host itself, and a group for each VM running on that host. For each VM and host, perfmon reads the parameter other-config:perfmon and uses this string to determine which variables to monitor, and under which circumstances to generate a message.

For example, the following shows an example of configuring a VM “CPU usage” alert by writing an XML string into the parameter other-config:perfmon:

xe vm-param-set uuid=vm_uuid other-config:perfmon=\

'<config>
    <variable>
        <name value="cpu_usage"/>
        <alarm_trigger_level value="0.5"/>
    </variable>
</config>'
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Note:

You can use multiple variable nodes.

After setting the new configuration, use the following command to refresh perfmon for each host:

xe host-call-plugin host=host_uuid plugin=perfmon fn=refresh
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If this refresh is not done, there is a delay before the new configuration takes effect, since by default, perfmon checks for new configuration every 30 minutes. This default can be changed in /etc/sysconfig/perfmon.

Valid VM elements

• name: The name of the variable (no default). If the name value is either cpu_usage, network_usage, or disk_usage, the rrd_regex and alarm_trigger_sense parameters are not required as defaults for these values are used.

• alarm_priority: The priority of the alerts generated (default 3).

• alarm_trigger_level: The level of value that triggers an alert (no default).

• alarm_trigger_sense: The value is high if alarm_trigger_level is a maximum value otherwise low if the alarm_trigger_level is a minimum value (the default high).

• alarm_trigger_period: The number of seconds that values (above or below the alert threshold) can be received before an alert is sent (the default is 60).

• alarm_auto_inhibit_period: The number of seconds this alert will be disabled after an alert is sent (the default is 3600).

• consolidation_fn: Combines variables from rrd_updates into one value. For cpu-usage the default is average, for fs_usage the default isget_percent_fs_usage and for all others - sum.

• rrd_regex: Matches the names of variables from xe vm-data-sources-list uuid=vm_uuid, to compute performance values. This parameter has defaults for the named variables:

  • cpu_usage
  • memory_internal_free
  • network_usage
  • disk_usage

If specified, the values of all items returned by xe vm-data-source-list whose names match the specified regular expression are consolidated using the method specified as the consolidation_fn.

Valid host elements

• name: The name of the variable (no default).
• alarm_priority: The priority of the alerts generated (default 3).
• alarm_trigger_level: The level of value that triggers an alert (no default).
• alarm_trigger_sense: The value is high when alarm_trigger_level is a maximum value otherwise low if the alarm_trigger_level is a minimum value. (default high)
• alarm_trigger_period: The number of seconds that values (above or below the alert threshold) can be received before an alert is sent (default 60).
• alarm_auto_inhibit_period: The number of seconds that the alert is disabled for after an alert is sent. (default 3600).
• consolidation_fn: Combines variables from rrd_updates into one value (default sum - or average)
• rrd_regex: A regular expression to match the names of variables returned by the xe vm-data-source-list uuid=vm_uuid command to use to compute the statistical value. This parameter has defaults for the following named variables:
  • cpu_usage
  • network_usage
  • memory_free_kib
  • sr_io_throughput_total_xxxxxxxx (where xxxxxxxxis the first eight characters of the SR-UUID).

SR Throughput: Storage throughput alerts must be configured on the SR rather than the host. For example:

xe sr-param-set uuid=sr_uuid other-config:perfmon=\
'<config>
    <variable>
        <name value="sr_io_throughput_total_per_host"/>
        <alarm_trigger_level value="0.01"/>
    </variable>
</config>'
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Generic example configuration

The following example shows a generic configuration:

<config>
    <variable>
    <name value="NAME_CHOSEN_BY_USER"/>
    <alarm_trigger_level value="THRESHOLD_LEVEL_FOR_ALERT"/>
    <alarm_trigger_period value="RAISE_ALERT_AFTER_THIS_MANY_SECONDS_OF_BAD_VALUES"/>
    <alarm_priority value="PRIORITY_LEVEL"/>
    <alarm_trigger_sense value="HIGH_OR_LOW"/>
    <alarm_auto_inhibit_period value="MINIMUM_TIME_BETWEEN_ALERT_FROM_THIS_MONITOR"/>
    <consolidation_fn value="FUNCTION_FOR_COMBINING_VALUES"/>
    <rrd_regex value="REGULAR_EXPRESSION_TO_CHOOSE_DATASOURCE_METRIC"/>
    </variable>

    <variable>
    ...
    </variable>

    ...
</config>
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Configure email alerts

You can configure XenServer to send email notifications when XenServer hosts generate alerts. The mail-alarm utility in XenServer uses sSMTP to send these email notifications. You can enable basic email alerts by using XenCenter or the xe Command Line Interface (CLI). For further configuration of email alerts, you can modify the mail-alarm.conf configuration file.

Use an SMTP server that does not require authentication. Emails sent through SMTP servers that require authentication cannot be delivered.

Enable email alerts by using XenCenter

1. In the Resources pane, right-click on a pool and select Properties.

2. In the Properties window, select Email Options.

3. Select the Send email alert notifications check box. Enter your preferred destination address for the notification emails and SMTP server details.

4. Choose your preferred language from the Mail language list. The default language for performance alert emails is English.

Enable email alerts by using the xe CLI

To configure email alerts, specify your preferred destination address for the notification emails and SMTP server:

xe pool-param-set uuid=pool_uuid other-config:mail-destination=joe.bloggs@example.com
xe pool-param-set uuid=pool_uuid other-config:ssmtp-mailhub=smtp.example.com:<port>
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XenServer automatically configures the sender address as noreply@<hostname>. However, you can set the sender address explicitly:

xe pool-param-set uuid=pool_uuid other-config:mail-sender=serveralerts@example.com
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When you turn on email notifications, you receive an email notification when an alert with a priority of 3 or higher is generated. Therefore, the default minimum priority level is 3. You can change this default with the following command:

xe pool-param-set uuid=pool_uuid other-config:mail-min-priority=level
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Note:

Some SMTP servers only forward mails with addresses that use FQDNs. If you find that emails are not being forwarded it might be for this reason. In which case, you can set the server host name to the FQDN so this address is used when connecting to your mail server.

To configure the language for the performance alert emails:

xe pool-param-set uuid=pool_uuid other-config:mail-language=ja-JP
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The default language for performance alert emails is English.

Further configuration

To further configure the mail-alarm utility in XenServer, create an /etc/mail-alarm.conf file containing the following:

root=postmaster
authUser=<username>
authPass=<password>
mailhub=@MAILHUB@
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/etc/mail-alarm.conf is a user-supplied template for sSMTP’s configuration file ssmtp.conf and is used for all alerts generated by XenServer hosts. It consists of keys where key=@KEY@ and @KEY@ is replaced by the corresponding value of ssmtp-key in pool.other_config. These values are then passed to ssmtp, allowing you to control aspects of the sSMTP configuration using values from pool.other_config. Note how @KEY@ (uppercase) corresponds to ssmtp-key (lowercase, prefixed by ssmtp-).

For example, if you set the SMTP server:

xe pool-param-set uuid=pool_uuid other-config:ssmtp-mailhub=smtp.example.com
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and then add the following to your /etc/mail-alarm.conf file:

mailhub=@MAILHUB@
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mailhub=@MAILHUB@ becomes mailhub=smtp.example.com.

Each SMTP server can differ slightly in its setup and may require extra configuration. To further configure sSMTP, modify its configuration file ssmtp.conf. By storing relevant keys in the mail-alarm.conf file, you can use the values in pool.other_config to configure sSMTP. The following extract from the ssmtp.conf man page shows the correct syntax and available options:

NAME
    ssmtp.conf – ssmtp configuration file

DESCRIPTION
    ssmtp reads configuration data from /etc/ssmtp/ssmtp.conf The file con-
    tains keyword-argument pairs, one per line. Lines starting with '#'
    and empty lines are interpreted as comments.

The possible keywords and their meanings are as follows (both are case-
insensitive):

    Root
    The user that gets all mail for userids less than 1000. If blank,
    address rewriting is disabled.

    Mailhub
        The host to send mail to, in the form host | IP_addr port :
        <port>. The default port is 25.

    RewriteDomain
    The domain from which mail seems to come. For user authentication.

    Hostname
        The full qualified name of the host. If not specified, the host
        is queried for its hostname.

    FromLineOverride
        Specifies whether the From header of an email, if any, may over-
        ride the default domain. The default is "no".

    UseTLS
    Specifies whether ssmtp uses TLS to talk to the SMTP server.
    The default is "no".

    UseSTARTTLS
        Specifies whether ssmtp does a EHLO/STARTTLS before starting TLS
        negotiation. See RFC 2487.

    TLSCert
        The file name of an RSA certificate to use for TLS, if required.

    AuthUser
        The user name to use for SMTP AUTH. The default is blank, in
        which case SMTP AUTH is not used.

    AuthPass
        The password to use for SMTP AUTH.

    AuthMethod
        The authorization method to use. If unset, plain text is used.
        May also be set to "cram-md5".
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Custom fields and tags

XenCenter supports the creation of tags and custom fields, which allows for organization and quick searching of VMs, storage and so on. For more information, see Monitoring System Performance.

Custom searches

XenCenter supports the creation of customized searches. Searches can be exported and imported, and the results of a search can be displayed in the navigation pane. For more information, see Monitoring System Performance.

Determine throughput of physical bus adapters

For FC, SAS and iSCSI HBAs you can determine the network throughput of your PBDs using the following procedure.

1. List the PBDs on a host.
2. Determine which LUNs are routed over which PBDs.
3. For each PBD and SR, list the VBDs that reference VDIs on the SR.
4. For all active VBDs that are attached to VMs on the host, calculate the combined throughput.

For iSCSI and NFS storage, check your network statistics to determine if there is a throughput bottleneck at the array, or whether the PBD is saturated.

Monitor host and dom0 resources with NRPE

Note:

The NRPE feature is available for XenServer Premium or Trial Edition customers. For more information about XenServer licensing, see Licensing. To upgrade, or to get a XenServer license, visit the XenServer website.

Users with the Pool Admin role can use any third-party monitoring tool that supports the Nagios Remote Plugin Executor (NRPE) to monitor resources consumed by your XenServer host and dom0 - the control domain of your host.

You can use the following check plugins to monitor host and dom0 resources:

NRPE is an on-premises service that runs in dom0 and listens on TCP port (default) 5666 for check execution requests from a monitoring tool. After a request arrives, NRPE parses it, finds the corresponding check command including the parameter’s details from the configuration file, and then runs it. The result of the check is sent to the monitoring tool, which stores the results of past checks and provides a graph showing the historical performance data.

Prerequisites

To be able to use NRPE to monitor host and dom0 resources, the monitoring tool you are using must meet the following prerequisites:

• The monitoring tool must be compatible with NRPE version 4.1.0.
• To allow communication between NRPE and the monitoring tool, the monitoring tool must support TLS 1.2 with ciphers ECDHE-RSA-AES256-GCM-SHA384 and ECDHE-RSA-AES128-GCM-SHA256, and the EC curve is secp384r1.

Constraints

• You can configure NRPE settings for an entire pool or for a standalone host that is not part of a pool. Currently, you cannot configure NRPE settings for an individual host in a pool.

• If you add a host to a pool that already has NRPE enabled and configured on it, XenCenter does not automatically apply the pool’s NRPE settings to the new host. You must reconfigure NRPE settings on the pool after adding the new host or configure the new host with same NRPE settings before adding it to the pool.

  Note:

  When reconfiguring NRPE settings on a pool after adding a new host, ensure the host is up and running.

• If a host is removed from a pool with NRPE enabled and configured on it, XenCenter does not alter the NPRE settings on the host or the pool.

Configure NRPE by using the xe CLI

You can configure NRPE by using the xe CLI or XenCenter. For more information on how to configure NRPE by using XenCenter, see Monitoring host and dom0 resources with NRPE.

After making configuration changes to NRPE, restart the NRPE service by using:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=restart
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Enable NRPE

NRPE is disabled by default in XenServer. To enable NRPE on a host’s control domain (dom0), run the following commands in the xe CLI:

1. Get the host UUID of the host that you want to monitor:

   xe host-list

2. Enable NRPE on the host:

   xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=enable

   If the operation runs successfully, this command outputs Success. When XenServer restarts, NRPE starts automatically.

To stop, start, restart, or disable NRPE:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=<operation>
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where operation is stop, start, restart, or disable.

Monitoring servers

This is a comma-delimited list of IP addresses or host names that are allowed to talk to the NRPE daemon. Network addresses with a bit mask (for example 192.168.1.0/24) are also supported.

View the current list of monitoring servers:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=get-config args:allowed_hosts
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Allow the monitoring tool to execute checks:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=set-config args:allowed_hosts=<IP address or hostname>
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Query all NRPE settings:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=get-config
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Configure multiple NRPE settings:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=set-config args:allowed_hosts=<IP address or hostname> args:ssl_logging=<SSL log level> args:debug=<debug log level>
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Logs

Debug logging

By default, debug logging is disabled.

To check whether debug logging is enabled, run the following command:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=get-config args:debug
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If debug: 0 is returned, debug logging is disabled.

To enable debug logging:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=set-config args:debug=1
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SSL logging

By default, SSL logging is disabled:

ssl_logging=0x00
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To check whether SSL logging is enabled, run the following command:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=get-config args:ssl_logging
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To enable SSL logging:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=set-config args:ssl_logging=0x2f
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Warning and critical thresholds

For some of these check plugins, you can set warning and critical threshold values so that if the value returned by a check plugin exceeds the threshold values, an alert is generated. The warning threshold indicates a potential issue and the critical threshold indicates a more serious issue that requires immediate attention. Although default values are set for the warning and critical thresholds, you can adjust the threshold values.

To query the default warning and critical threshold values for all the checks, run the following xe CLI command which returns a list of all the checks and their associated warning and critical thresholds:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=get-threshold
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You can also query the threshold values for a specific check. For example, to get the warning and critical threshold values for the check_memory check plugin, run the following xe CLI command:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=get-threshold args:check_memory
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You can also change the default value of a threshold. For example, to change the default threshold values for the check_memory check plugin, run the following xe CLI command:

xe host-call-plugin host-uuid=<host uuid> plugin=nrpe fn=set-threshold args:check_memory args:w=75 args:c=85
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Monitor host and dom0 resources with SNMP

Note:

The SNMP feature is available for XenServer Premium or Trial Edition customers. For more information about XenServer licensing, see Licensing. To upgrade, or to get a XenServer license, visit the XenServer website.

With the Pool Admin role, you can use SNMP to remotely monitor resources consumed by your XenServer host and dom0 - the control domain of your host. An SNMP manager, also known as a network management system (NMS), sends query requests to an SNMP agent running on a XenServer host. The SNMP agent replies to these query requests by sending data collected on various metrics back to the NMS. The data that can be collected is defined by object identifiers (OIDs) in a text file called a management information base (MIB). An OID represents a specific piece of measurable information about a network device, such as CPU or memory usage.

You can also configure traps, which are agent-initiated messages that alert the NMS that a specific event has occurred in XenServer. Both query requests and traps can be used to monitor the status of your XenServer pools. These are defined as metric and trap objects and are identified by OIDs in a MIB file XENSERVER-MIB.txt, available to download from the XenServer Downloads page. The following tables provide information about these metric and trap objects.

Metric objects

You can request a specific piece of information about your XenServer hosts by using the metrics listed in the following table. These metrics are used by the SNMP manager when sending query requests to an SNMP agent and so you can view this data in your NMS.

You can view the returned data from these metric objects from your NMS or from the xe CLI. To query the metric objects from the xe CLI, run host-data-source-query or vm-data-source-query and provide the RRDD data source as a value for the data-source parameter. For example:

xe host-data-source-query data-source=cpu_avg host=<host UUID>
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Note:

By default, the NMS sends OID query requests to SNMP agents using port 161.

Notes:

1. The name of a pCPU is in the format cpu followed by a number. To query the number of pCPUs from the xe CLI, run the following command:

   xe host-data-source-list host=<host UUID> | grep -E 'cpu[0-9]+$'

   This returns a list of the CPU metrics that match the regular expression cpu[0-9]+.

Traps

Traps are alerts sent by the SNMP agent to notify the SNMP manager when certain events occur, allowing you to monitor your XenServer hosts and identify issues early. You can configure your SNMP settings to generate a trap when a limit is reached (for example, if the host CPU usage is too high). When a trap is generated, it is sent to your NMS and the following fields are returned as part of the trap object.

Note:

By default, the SNMP agent on the pool coordinator host sends traps to the NMS using UPD port 162.

Prerequisites

• All hosts in a pool must be running the same XenServer version and this version must contain the SNMP plugin.

  Note:

  If you cannot see the SNMP tab in XenCenter, it might be because the host or a member of the pool is not running a version of XenServer that supports SNMP. Update the host or pool to the latest version of XenServer.

• The NMS you are using must support SNMPv2c or SNMPv3.

• Your NMS and XenServer must be network-connected.

Constraints

• You can configure SNMP settings for an entire pool or for a standalone host that is not part of a pool. Currently, you cannot configure SNMP settings for an individual host in a pool.

• If you add a host to a pool that already has SNMP enabled and configured on it, XenCenter does not automatically apply the pool’s SNMP settings to the new host. You must reconfigure SNMP settings on the pool after adding the new host or configure the new host with the same SNMP settings before adding it to the pool.

  Note:

  When reconfiguring SNMP settings on a pool after adding a new host, ensure the host is up and running and not in maintenance mode.

• Before performing a rolling pool upgrade from Citrix Hypervisor 8.2 CU1 to XenServer 8 or applying updates to your XenServer hosts and pools, back up the following configuration files if you manually modified them before and need them:

  • /etc/snmp/snmpd.xs.conf
  • /etc/sysconfig/snmp
  • /var/lib/net-snmp/snmpd.conf
• When the SNMP agent is offline, traps cannot be generated. For example, if the SNMP agent is restarted or the pool coordinator is rebooted or re-designated.

Configure SNMP by using the xe CLI

You can configure SNMP by using the xe CLI or XenCenter. For more information on how to configure SNMP by using XenCenter, see Monitoring host and dom0 resources with SNMP.

result objects

When configuring SNMP, all responses are returned in JSON format. If a command executes successfully, it returns the key value pair "code": 0. Some commands (such as the get-config command) return a nested JSON object called result. The result JSON object is also required for the set-config command which is used to update the SNMP configuration.

The result JSON object is made up of the following objects common, agent, and nmss:

common

agent

nmss

Notes:

1. COMMON_STRING_TYPE refers to a string that meets the following requirements:
   • Any combination of letter, number, hyphen (-), period (.), pound (#), at sign (@), equals (=), colon (:) or underscore characters (_).
   • Length between 6 and 32 inclusive.
2. Passwords are not stored in plaintext in any configuration file in XenServer. They are converted to a localized key and stored. The get-config command shows the password as a hidden constant comprised of asterisks (*).

Configure the SNMP service

Get the status of the SNMP service:

xe host-call-plugin host-uuid=<host-uuid> plugin=snmp fn=status
<!--NeedCopy-->

Start, stop, or restart the SNMP service:

xe host-call-plugin host-uuid=<host-uuid> plugin=snmp fn=<operation>
<!--NeedCopy-->

where operation is start, stop, or restart.

Get the SNMP configuration details:

xe host-call-plugin host-uuid=<host-uuid> plugin=snmp fn=get-config
<!--NeedCopy-->

If successful, this command returns the key value pair "code": 0 and the result JSON object containing the configuration details of the SNMP service. For example:

"code": 0,
  "result": {
    "common": {
      "enabled": "no",
      "debug_log": "no",
      "max_nmss": 1
    },
    "agent": {
      "v2c": "yes",
      "v3": "no",
      "community": "public",
      "user_name": "",
      "authentication_password": "",
      "authentication_protocol": "",
      "privacy_password": "",
      "privacy_protocol": "",
      "engine_id": "<engine_id>"
    },
    "nmss": []
  }
<!--NeedCopy-->

Copy the result JSON object to your preferred text editor and remove all newline (\n) characters from the file. Update the fields with your SNMP configuration details. Configure your NMS by referring to your NMS documentation and specifying values for the fields required for the nmss object. For more information, refer to the objects listed above.

To configure the SNMP service, run the set-config command and provide the edited result JSON object as a parameter value to the args:config parameter.

Set the SNMP configuration:

xe host-call-plugin host-uuid=<host-uuid> plugin=snmp fn=set-config args:config='<result>'
<!--NeedCopy-->

where result is the result JSON object returned from the get-config command that you copied and edited.

Note:

To configure SNMP for an entire pool, you must run the set-config command for each host in the pool.

If the configuration changes are successful, the command returns the key value pair "code": 0. If the configuration changes are unsuccessful, the set-config command returns one of the following key value pairs which indicate that an error has occurred:

• "code": 1: Common error string. For example, an unknown exception.
• "code": 2: Error string (parameter is missing).
• "code": 3: Returns a message object as a list where each element is in the format of [field_path, key, value, error string].

You can also send a test SNMP trap to your NMS to verify that the specified trap receiver information is correct.

Send a test SNMP trap:

xe host-call-plugin host-uuid=<host-uuid> plugin=snmp fn=send-test-trap args:config='{"nmss":[{"uuid":"<uuid>","address":"<address>","port":162,"v2c":"yes","v3":"no","community":"public","user_name":"<user_name>","authentication_password":"<authentication_password>","authentication_protocol":"<authentication_protocol>","privacy_password":"<privacy_password>","privacy_protocol":"<privacy_protocol>"}]}'
<!--NeedCopy-->

This command sends a test trap to your NMS with the msg_name of TEST_TRAP and the msg_body of This is a test trap from XenServer pool "<pool name>" to verify the NMS Trap Receiver configuration.

If you do not receive the test trap, check your SNMP configuration again. If unsuccessful, the send-test-trap command also returns one of the following key value pairs which indicate that an error has occurred:

• "code": 1: Common error string. For example, an unknown exception.
• "code": 2: Error string (parameter is missing).
• "code": 3: Returns a message object as a list where each element is in the format of [field_path, key, value, error string].
• "code": 4: Returns a message object as a list where each element is in the format of [nms address, nms port, error string].