34,333
edits
Changes
New page: <table border="0" cellspacing="0" width="100%"> <tr> <td width="20%">Previous<td align="center">[[Fedora Linux Essentials|Table of ...
<table border="0" cellspacing="0" width="100%">
<tr>
<td width="20%">[[Installing and Configuring Fedora Xen Virtualization|Previous]]<td align="center">[[Fedora Linux Essentials|Table of Contents]]<td width="20%" align="right">[[Installing a Xen Guest OS from the Command-line (virt-install)|Next]]</td>
<tr>
<td width="20%">Installing and Configuring Fedora Xen Virtualization<td align="center"><td width="20%" align="right">Installing a Xen Guest OS from the Command-line (virt-install)</td>
</table>
<hr>
In the previous chapter ([[Installing and Configuring Fedora KVM Virtualization]]) we covered the steps necessary to configure the Fedora operating system to act as a KVM host system and created, installed and ran a KVM guest system.
In this chapter we will explore the use of the ''virt-manager'' tool to manage the KVM guest operating systems.
== Starting and Stopping KVM Guest Systems ==
When a KVM virtual guest system has been configured it will appear in the list of systems when the ''virt-manager'' is loaded. The ''virt-manager'' tool is launched either by selecting the Applications->System Tools->Virtual Machine Manager or from the command-line by running /usr/sbin/virt-manager. If ''virt-manager'' shows the host system as being disconnected, connect to it either by double clicking on the host in the list or right click on it and select ''Connect'' from the resulting menu.
The following screenshot shows the ''virt-manager'' tool running on a Fedora system. It lists one connected host system (localhost), and two guest virtual systems named ''kvm-fedora2'' and ''virt-fedora'' both of which are currently shut down:
[[Image:kvm_virt_manager_host_shutoff.jpg| The KVM Virtual Machine Manager with Guest systems Shut Down]]
To launch a guest virtual OS, either double click on the OS in the list, or right click on the system and select ''Run'' from the context menu.
To stop a virtual machine running a guest OS it is not sufficient to simply close the Virtual Machine Console and Virtual Machine Manager windows. Doing so only closes the manager and console, leaving the guest operating system running in the background. In fact, if you try closing these windows and then restart the ''virt-manager'' tool you will see the guest OS is still listed as running, and selecting ''open'' will display the guest OS exactly as it was before you closed the console window.
To shutdown a guest OS, either shut it down using the operating system's own shut down mechanism, click on ''Shutdown'' in the Virtual Machine Console toolbar, or right click on the guest OS from the list in the ''virt-manager'' main screen and select ''Shutdown''.
== Pausing a KVM Guest Operating System ==
KVM provides the ability to pause and resume a running guest operating system. To pause a running system, either click the ''Pause'' button in the Virtual Machine Console toolbar, or right click the operating system in the ''virt-manager'' main screen and select ''Pause''.
A paused guest OS may then be resumed either by clicking again on the ''Pause'' button in the Virtual Machine Console toolbar, or right click the operating system in the ''virt-manager'' main screen and select ''Resume''.
Note that a paused guest system will not survive the reboot of the host operating system and continues to use system memory in the paused state. In the event that the host operating system is rebooted, the guest operating system will need to be restarted and cannot be resumed from its paused state.
== Changing KVM Guest Operating System Settings ==
During the initial configuration of the guest OS in ''virt-manager'' a number of resources such as memory allocation and CPU usage were defined. It is common to discover after the guest OS starts running that these settings need to be changed. Fortunately, ''virt-manager'' makes it easy to change these settings.
To modify the settings for a specific guest operating system, start ''virt-manager'' (''Applications->System Tools->Virtual Machine Manager''), select the desired guest operating system and click on the ''Details'' button. When the ''Virtual Machine Details'' dialog appears, click on the ''Hardware'' tab to view the current settings:
[[Image:kvm_hardware_settings.jpg| Xen Virtual Machine Details - Hardware]]
The hardware screen initially displays the CPU settings, allowing the number of CPUs used by the virtual machine to modified.
The panel on the left allows the current displayed category to be changed. For example, to change the memory assigned to the guest system, select the Memory option and change the settings as required:
[[Image:xen_hardware_memory_settings.jpg| Xen Virtual Machine Details - Memory]]
Additional disks may be added by clicking on the ''Add'' button at the bottom of the hardware category list, selecting ''Storage device'' from the ''Hardware type'' menu and clicking on ''Forward''. Specify either a disk partition, or a file location to act as the new disk.
== Monitoring Virtual Machine Performance ==
The ''virt-manager'' tool provides information on CPU and memory usage for each guest operating system. To view the performance graphs, select the desired guest OS in the ''virt-manager'' main window and click on ''Details''. The ''Virtual Machine Details'' screen will display two real-time graphs showing the Memory and CPU usage for the selected guest:
[[Image:xen_monitoring.jpg|Monitoring Xen Guest memory/cpu Performance]]
In addition, the ''virt-manager'' main window displays smaller CPU graph and Memory scale next to each guest OS together with a bar indicating the percentage of overall available memory used by each operating system:
[[Image:xen_memory_percentage.jpg|Xen VM memory percentage usage]]
The overall performance statistic of the host operating system may similarly be viewed by selecting the host OS in ''virt-manager'' (typically Domain-0) and clicking ''Edit->Machine details...''.
<tr>
<td width="20%">[[Installing and Configuring Fedora Xen Virtualization|Previous]]<td align="center">[[Fedora Linux Essentials|Table of Contents]]<td width="20%" align="right">[[Installing a Xen Guest OS from the Command-line (virt-install)|Next]]</td>
<tr>
<td width="20%">Installing and Configuring Fedora Xen Virtualization<td align="center"><td width="20%" align="right">Installing a Xen Guest OS from the Command-line (virt-install)</td>
</table>
<hr>
In the previous chapter ([[Installing and Configuring Fedora KVM Virtualization]]) we covered the steps necessary to configure the Fedora operating system to act as a KVM host system and created, installed and ran a KVM guest system.
In this chapter we will explore the use of the ''virt-manager'' tool to manage the KVM guest operating systems.
== Starting and Stopping KVM Guest Systems ==
When a KVM virtual guest system has been configured it will appear in the list of systems when the ''virt-manager'' is loaded. The ''virt-manager'' tool is launched either by selecting the Applications->System Tools->Virtual Machine Manager or from the command-line by running /usr/sbin/virt-manager. If ''virt-manager'' shows the host system as being disconnected, connect to it either by double clicking on the host in the list or right click on it and select ''Connect'' from the resulting menu.
The following screenshot shows the ''virt-manager'' tool running on a Fedora system. It lists one connected host system (localhost), and two guest virtual systems named ''kvm-fedora2'' and ''virt-fedora'' both of which are currently shut down:
[[Image:kvm_virt_manager_host_shutoff.jpg| The KVM Virtual Machine Manager with Guest systems Shut Down]]
To launch a guest virtual OS, either double click on the OS in the list, or right click on the system and select ''Run'' from the context menu.
To stop a virtual machine running a guest OS it is not sufficient to simply close the Virtual Machine Console and Virtual Machine Manager windows. Doing so only closes the manager and console, leaving the guest operating system running in the background. In fact, if you try closing these windows and then restart the ''virt-manager'' tool you will see the guest OS is still listed as running, and selecting ''open'' will display the guest OS exactly as it was before you closed the console window.
To shutdown a guest OS, either shut it down using the operating system's own shut down mechanism, click on ''Shutdown'' in the Virtual Machine Console toolbar, or right click on the guest OS from the list in the ''virt-manager'' main screen and select ''Shutdown''.
== Pausing a KVM Guest Operating System ==
KVM provides the ability to pause and resume a running guest operating system. To pause a running system, either click the ''Pause'' button in the Virtual Machine Console toolbar, or right click the operating system in the ''virt-manager'' main screen and select ''Pause''.
A paused guest OS may then be resumed either by clicking again on the ''Pause'' button in the Virtual Machine Console toolbar, or right click the operating system in the ''virt-manager'' main screen and select ''Resume''.
Note that a paused guest system will not survive the reboot of the host operating system and continues to use system memory in the paused state. In the event that the host operating system is rebooted, the guest operating system will need to be restarted and cannot be resumed from its paused state.
== Changing KVM Guest Operating System Settings ==
During the initial configuration of the guest OS in ''virt-manager'' a number of resources such as memory allocation and CPU usage were defined. It is common to discover after the guest OS starts running that these settings need to be changed. Fortunately, ''virt-manager'' makes it easy to change these settings.
To modify the settings for a specific guest operating system, start ''virt-manager'' (''Applications->System Tools->Virtual Machine Manager''), select the desired guest operating system and click on the ''Details'' button. When the ''Virtual Machine Details'' dialog appears, click on the ''Hardware'' tab to view the current settings:
[[Image:kvm_hardware_settings.jpg| Xen Virtual Machine Details - Hardware]]
The hardware screen initially displays the CPU settings, allowing the number of CPUs used by the virtual machine to modified.
The panel on the left allows the current displayed category to be changed. For example, to change the memory assigned to the guest system, select the Memory option and change the settings as required:
[[Image:xen_hardware_memory_settings.jpg| Xen Virtual Machine Details - Memory]]
Additional disks may be added by clicking on the ''Add'' button at the bottom of the hardware category list, selecting ''Storage device'' from the ''Hardware type'' menu and clicking on ''Forward''. Specify either a disk partition, or a file location to act as the new disk.
== Monitoring Virtual Machine Performance ==
The ''virt-manager'' tool provides information on CPU and memory usage for each guest operating system. To view the performance graphs, select the desired guest OS in the ''virt-manager'' main window and click on ''Details''. The ''Virtual Machine Details'' screen will display two real-time graphs showing the Memory and CPU usage for the selected guest:
[[Image:xen_monitoring.jpg|Monitoring Xen Guest memory/cpu Performance]]
In addition, the ''virt-manager'' main window displays smaller CPU graph and Memory scale next to each guest OS together with a bar indicating the percentage of overall available memory used by each operating system:
[[Image:xen_memory_percentage.jpg|Xen VM memory percentage usage]]
The overall performance statistic of the host operating system may similarly be viewed by selecting the host OS in ''virt-manager'' (typically Domain-0) and clicking ''Edit->Machine details...''.