What is a KVM switch? Its connection diagram. How to connect a KVM guest to the Internet using a wireless network Connecting a kvm switch

Because my wireless network adapter does not support bridges, it is very difficult to force the guest virtual machine to connect to the open internet and have an IP address on the same network as the host. I'm using Ubuntu 10.10 and the KVM version doesn't support vde so it gets even more complicated. How can I fix this?

@stribika's idea is great, but I'd rather have my VMs connected to the same network as my host. for example my host network is 192.168.1.0 and I want my network virtual machine was the same.

2 Solutions collect form web for “How to connect a KVM guest to the Internet using a wireless network”

You should be able to use the network stack user mode. Start qemu like this:

Qemu-system-x86_64 \ -smp 1 -m 1024 \ -net user,net=10.0.0.0/8,host=10.0.0.1,hostfwd=tcp:127.0.0.1:2222-10.0.0.2:22 \ -net nic \ -cdrom systemrescuecd-x86-2.0.1.iso -boot d

Important options:

• -net nic: Show virtual network card for a guest
• -net user: force the qemu process on the host to communicate over the real network like any other process
• net=10.0.0.0/8: subnet in the virtual network
• host=10.0.0.1: IP address of the host in the virtual network
• hostfwd=tcp:127.0.0.1:2222-10.0.0.2:22: The qemu process on the host listens for TCP connections from localhost on port 2222 and forwards them to the virtual network before 10.0.0.2:22 (so you can ssh into your new virtual car)

From a guest perspective

Ifconfig eth0 10.0.0.2 up ip route add default via 10.0.0.1 dev eth0

SSH test from host to guest

Ssh 127.0.0.1 -p 2222

and from the guest to the host

Ssh 10.0.0.1

Check the guest's Internet availability

Wget google.com

The host process acts as a NAT router. Only TCP and UDP traffic will work. Specifically, ping only works between guest and host, you can't ping google.com (my usual network testing method). The advantage of this approach is that you don't even need root privileges.

Catch-22: The host cannot pass ssh to the guest when the whole purpose of connecting to the internet is to install an openssh server on the guest.

The need to control several computers at once from one set of keyboard and mouse often arises in work environments. This is what they are used for KVM switches(“Keyboard, Video, Mouse”). In recent years, such switches have been replaced by numerous programs that allow you to do the same through local network or the Internet, but switches are still used where maximum reliability is needed - software can sometimes fail.

KVM switches are used both in offices (desktop models) and in server rooms (models for server racks). Choosing the right model is not as easy as it seems at first glance.

In the next section, we will look at the most important characteristics of KVM switches, and then present to your attention several models that can be purchased in our catalog stores.

Key Features You Should Pay Attention to

The scope of its application depends on the design of the switch housing. For offices, they buy desktop models that do not take up much space and are designed for 2-4 machines (both regular PCs and servers that are not located in a rack).

KVM-over-IP - switches that allow you to control your PC via global network Internet. This is a separate category, which has not been so popular lately due to the fact that similar functionality is available in the servers themselves.

A KVM extender is two devices (one on the computer side, the other on the peripheral side) that allow control remotely, but not via the Internet or local network.

A KVM console is a special device for server rooms, which when folded takes up 1U in a rack. When unfolded, it consists of a screen, keyboard and touchpad (or other device that replaces a mouse).

Also, the most powerful and multifunctional switches are installed in server racks - for 8 or more machines. They do not have a screen or keyboard; to connect them, the server cabinet must have additional shelves.

Number of connected computers

The main characteristic of any KVM switch. The more computers you can connect to it, the more expensive it will be, and the dimensions of the device will be larger. If you are choosing a model for the office, then 2 or 4 connections will probably be enough (the ports to which computers are connected are called “console ports”). If we are talking about use in a server room or server room, then the limit does not exist.

Supported Monitor Resolution

Be sure to make sure that the switch you purchase supports the resolution of the monitors that will be used in conjunction with it. With modern models this problem disappears, but keep in mind that switches are not designed for monitors high resolutions(for example, 4K).

Console connections

First of all, you need to determine which computers with which video outputs will connect to the KVM switch. These can be VGA (analog and legacy; maximum resolution - 1280x1024 pixels), DVI (digital; up to 1920x1080 pixels) DisplayPort or HDMI (digital; up to 2560x1440 pixels).

Next, you need to pay attention to the keyboard and mouse ports. The best option- USB, but if the server or computer has PS/2 ports, they will also work. Please note that most models do not work with wireless peripherals.

More advanced and expensive KVM switches allow you to connect not only computers, but also other devices - printers, audio devices, modems, removable drives and so on. For this purpose they are used USB ports, 3.5 mm audio outputs and audio inputs, as well as a variety of interfaces such as RJ-45 or RS-232.

Control and display

Typically, the switch is controlled using one button on the case or remote control, which alternately changes the active console port. More advanced models have separate buttons for each port. Special indicators indicate the port that is active at a particular moment.

Nutrition

Based on the type of power supply, KVM switches are divided into passive and active. Passive models receive power from the keyboard and mouse interfaces. Sometimes they may simply not work due to lack of power, but in recent years this problem has been extremely rare.

Active KVM switches use their own power adapter, which is included in the kit. This is a more reliable, but also more expensive option - only server switches are usually equipped with their own adapter.

Hello! Today I propose to discuss an interesting and useful topic. I touched on it not by chance, but due to the fact that I am building a home server.

For those interested, here it is Part one- http://site/vybiraem-domashnij-server-chast-1.html and part two- http://site/sborka-domashnego-servera-chast-2.html

Accordingly, I needed to quickly switch between workstations. One of possible solutions I propose to sort it out today.

Go! Sometimes there is a need to work on several computers at once, or quite often connect/disconnect other computers for setup or repair. In this case, constantly switching the keyboard, monitor and mouse from one computer to another is not the best suitable option. Of course, you can put 2 monitors, 2 keyboards and 2 mice on the table, but this is quite expensive and eats up a lot of work space.

There is a fairly simple convenient solution this task is KVM-Switch. Let's figure out what it is and how to work with it.

KVM-Switch or KVM switch is a special device designed to connect one set of input/output devices to several computers. Speaking in simple words A KVM switch allows you to connect one keyboard, mouse and one monitor to multiple system units, and then switch to control any computer with the press of a button.

This is what a typical representative of the KVM family looks like:

In the photo above we see 1 VGA connector for connecting to a monitor and two connectors for connecting a mouse and keyboard. On the reverse side there are 2 VGA connectors for connecting to two system units via special cables. This is what they look like:

There is a wide variety of KVM switches and they have different characteristics, the key one being the number of connected computers. There are two-, four-, and more port switches. Also, they may differ in the types of outputs usb or ps/2, vga or dvi, which allows you to choose the desired option. Some KVMs have the ability to switch audio.

Almost all modern KVMs do not require separate power, but receive it through PS/2 or USB connectors, which saves us from unnecessary wires.

This is what the diagram for connecting computers via KVM switch looks like:

Switching between computers occurs by pressing one button on the device itself. It is also often possible to switch programmatically by double-clicking the Scroll Lock key.

Some might argue that there are special programs remote access, for example, TeamViewer, which allow you to control another computer without any extra devices. However, these programs are designed for other purposes. Considering that KVM switches do not depend on the operating system at all and switch at the circuit level, they allow you to perform absolutely any actions with connected computers, for example, setting up the BIOS.

Thus, we can connect two computers, on one of which we will work in the operating system, and on the other, we will run tests or install the OS. Another example - you can run a complex task on one of the computers, for example, video processing or copying a large amount of data, and then switch to another computer and continue surfing the Internet)). Convenience, and that’s it!

Such devices can often be seen in server rooms, where there are usually several servers installed and only one monitor, one keyboard and mouse.

In this way, you can organize comfortable work at several stations at once.

KVM over IP - what is it?

KVM(or kvm over ip) is a device that allows you to transmit video signals and mouse/keyboard input over a network using the IP protocol from your server. Using KVM, you can reboot the server, access the server's BIOS, and other functions that cannot be performed on the server through a terminal. You can connect KVM access for free on the services page.

KVM is provided free of charge for the first two hours of the day. The fee for subsequent KVM connection is 30 minutes - 300 rubles.

How to connect KVM to the server?

Ready! You will receive KVM access to the server for a selected period of time (up to 2 hours). Within 15-20 minutes, access will be sent to your contact e-mail.

KVM doesn't work

Working through utilities

When working through utilities, there is no need to configure Java.
For KVM management Windows users can use the utilities:

• CN8000 WinClient
• — for KVM from the manufacturer ATEN;
• — for KVM from the manufacturer ATEN;
• KVM Vision Viewer - for KVM from other manufacturers.

Working in the browser

To work with KVM, the browser must support Java. Opera and Chrome browsers (starting from Cromium 42) and the standard edition of Firefox (versions above 52) no longer support Java. Of the updated browsers, Java support is in Firefox ESR (until March 2018).

The operation of the web interface for KVM CN8000A models is guaranteed only in browsers based on the Gecko engine (for example, FireFox). In Webkit (Chromium and those based on it) there may be problems with displaying elements. In this case, we recommend using Windows or Java clients.

If the KVM console has a black screen, the message “No Signal”

In case of prolonged inactivity, the screen will turn off (the message “No Signal” will appear); to resume, you must press any key in the console (we recommend pressing “Alt” or “Ctrl” instead of “Enter” to avoid executing the command typed in the console earlier).

Keyboard not working in KVM console

Try resetting the KVM device. To do this, log in to the KVM web interface, go to the “Maintenance” section and perform a reset. Usually this item is called “Unit Reset”, “Reset USB”. 2 minutes after the reset, check the operation of the keyboard in the KVM.

What to do if the KVM window in Java does not open

If the KVM window does not open for a long time, check whether Java is installed on your PC. Go to the official Java website, then click on the link “Do I have Java software installed on my computer? " If Java is installed, then follow the instructions below.

If Java version 8 is installed

To launch the KVM console you need to complete three steps:

1. 1.

   Make changes to the file java.security. The file is located in JDK_HOME/jre/lib/security/java.security, usually these are the paths:
   

   for Windows OS:
   C:\Program Files\Java\jre1.8.0_91\lib\security for 64-bit versions of JAVA or
   C:\Program Files (x86)\Java\jre1.8.0_91\lib\security for 32-bit versions.
   

   for Linux OS:
   /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/security/java.security
   or you can find the file with the command in Linux consoles:
   find /usr/lib/ -name java.security
   

   In this file you need to comment out the line that begins with:

   jdk.certpath.disabledAlgorithms
   those. add a "#" symbol at the beginning of the line, for example:
   # jdk.certpath.disabledAlgorithms=MD2, RSA keySize

   Please note that to edit a file java.security need to run text editor as administrator (for Windows) or superuser root (for Linux).

If the problem persists, try installing Java 7 and setting the security level to Medium (see above).

If the methods listed above did not help you and any error messages appear when opening the KVM window, you should refer to the official JAVA manual on the developer’s website: http://java.com/en/download/help/

As a solution, try using Windows OS and browser Internet Explorer version 9.
It is also possible to work in Linux systems x32 when using Firefox and version 7 of Java.
Additionally, you can use the emulation mode for older browsers in Internet browser Explorer 11 (accessible by pressing the F12 button).

What to do if a KVM window in Java opens from the browser, but there is an error in the status bar?

Information about blocking messages Java works in the browser is located at the link.

What is IPMI and why is it needed?

IPMI- interface for remote control server. It is designed for autonomous monitoring and management of functions built into the server hardware.

IPMI operates regardless of the operating system on the server. Therefore, if problems are detected with the processor / BIOS / operating system, you can reboot the server and restore critical management, logging and inventory functions via IPMI. You can read more about IPMI on thematic forums.

IPMI Interface Access

If you have problems with console display and IPMI availability, use the instructions: . If any difficulties arise, write.

Installing an operating system using IPMI

You can install the operating system yourself using IPMI. The IPMI interface allows you to remotely install the OS and connect the image file as a virtual DVD-ROM on the server.

The following images are available for loading into IPMI:

• Centos 6, 7;
• Debian 8, 9;
• Ubuntu 14, 16, 18;
• ESXI 6.5, 6.7;
• SystemRescueCd 5.3.2.

If you need to download another image, please write with a link to the image.

To install the operating system, follow these steps:

1. 3.

   On the Manage tab, click IPMI Console:

2. 4.

   On first transition confirm launch:

   • in the first pop-up window, check the box next to “Always trust content from this publisher” and click the button Run:
   • in the second pop-up window click the button Yes:
3. 5.

   In the Web IPMI window, select Virtual Media — Virtual storage:

4. 6.

   In the “Logical Drive Type” field, select the image type ISO File, in the “Image File Name and Full Path” field, select the distribution file (any .iso file), click Plug in, Further OK:

5. 7.

   Reboot the server in the console window Macro — Macro — Ctrl+Alt+Del:

6. 8.

   After this, the “Virtual DVD” device will appear in the server BIOS, which can be set first in the boot order of disks ( Boot priority ):

7. 9.

   Save changes by selecting "Save changes and exit" in the "Exit" menu:

8. 10.

   Boot from the virtual DVD and install the operating system.

If you have problems with console display and IPMI availability, use the instructions: . If any difficulties arise, write.

It is important to know

The IPMI controller forwards to motherboard virtual DVD-ROM and keyboard control via the USB bus, so you cannot disable support for USB devices in the BIOS or OS.

What to do if IPMI does not work?

Ways to solve IPMI console display problems (for example, black screen):

Press any key on the keyboard (for example, Shift). If your keyboard doesn't work, use the virtual keyboard.

For a server with operating system Ubuntu - Press keyboard shortcut Ctrl + Alt + F1.

Reboot IPMI (cold reset) by connecting to the server via SSH as root and running the command: ipmicfg -r or ipmitool bmc reset cold .

The ipmitool utility requires some kernel modules; you can enable them using the command in the server console from the root user: modprobe ipmi_si && modprobe ipmi_devintf && modprobe ipmi_msghandler.

• For a server with operating system Windows system Server - connect as the Administrator user and in command line enter the command: ipmicfg-win.exe -r .

If the above methods do not resolve the issue, follow these steps:

Connection failed error

Reset IPMI. For this:

Keyboard doesn't work

If the IPMI console still does not respond to keyboard inputs, use the virtual keyboard.

From the Virtual Media menu, select Virtual Keyboard:

To return to physical keyboard control in the IPMI console, select the Options menu item. Keyboard Mouse Hotplug:

If you need to hide virtual keyboard, in the “Exit” menu, select Exit:

After that, close the IPMI console and open it again. The IPMI reboot may take up to five minutes.

If any difficulties arise, write.

With the arrival of broadband Internet in offices, full-fledged remote administration has become possible. Thanks to this technology, service organizations were able to significantly reduce the response time to a client request, and system administrators got the opportunity to provide support even while outside the office. But the tools remote administration work only after the OS boots, if for some reason this is impossible, the physical presence of a specialist will be required. KVM over IP switches can solve this problem.

All administrators probably know what KVM switches are; this is a device that allows you to use one console (monitor, keyboard and mouse) to control several PCs. KVM switches can be as simple as those designed for personal use:

So also for rack mounting, supporting cascading and allowing you to manage a large number of servers at once (up to several hundred) from one place:

What stands out in this company are KVM over IP switches, which allow you to access the PC console from anywhere via the TCP/IP protocol. For a long time These devices were considered “luxury items”, but recently offers have appeared on the market at a very reasonable price, making them quite affordable for small organizations.

Let's look at the capabilities of a KVM over IP switch using an example ATEN ALTUSEN KH1508i costing 727 USD. In addition to the attractive price this device allows you to control up to 256 PCs (when cascading switches), supports PC, Mac, Sun platforms, PC connections via PS/2 and USB.

The switch is made in 1U format and can be rack mounted. The front panel contains output switching buttons, an active port indicator, a connector for firmware updates, a power indicator and a Reset button.

Another feature of the switch is the use of twisted pair UTP 5e to connect managed PCs, which allows them to be placed at a distance of up to 40 m. Now there is no problem connecting servers located in the next rack (or on the floor below) and there is no need to rack your brains over purchasing and laying expensive specialized cables. Connectors for connecting controlled PCs, network, slave switches and the console are located on the back of the switch:

To connect managed PCs, client modules are used that emulate the necessary peripherals. Emulation is performed directly by the module, regardless of the presence of a control device. This means that if you forget to turn the switch on, your managed PCs will still detect your keyboard, mouse, and monitor when they boot up, and you won't have to reboot them to gain access.

The manufacturer offers a wide selection of client computer control modules different platforms, two types of client modules are available for PCs: KA9520 (PS/2) and KA9570 (USB) costing 71 USD. Each module is a controller with an RJ-45 interface and a half-meter cable with VGA connectors and PS/2 (USB), has its own firmware, regularly updated by the manufacturer; there is a switch on the module body that switches it to firmware update mode. The KA9520 module is shown below:

For mounting on a vertical surface, a special basket is supplied with the module.

Switch settings are made through the on-screen menu or web interface (to a somewhat limited extent). If you don't have Mac computers or Sun, then all settings will be available via the web (by default, all switch ports are configured for the PC platform).

The connection to the device is made via the secure HTTPS protocol, despite the fact that the switch accepts connections on port 80, it is still redirected to the secure connection (port 443). Port 9000 is used to transfer data between the switch and the client program; this should be taken into account when forwarding ports (i.e., in addition to 80 and/or 443, you also need to forward 9000).

Let's move on to network functions switch, by default it is configured to receive settings via DHCP, which, in our opinion, is much better than a pre-set IP, just look at what address is assigned to the device in the DHCP server settings and reserve it for the appropriate MAC address(indicated on the device body).

To access, you can use any browser (optimally IE), the web interface is not rich in settings, you can launch Windows (only through IE) or a Java client, or download them if you can’t launch them through the browser in any way.

The parameter deserves special attention Network Transfer Rate, for comfortable work with the device, you should specify the minimum guaranteed speed of the channel through which the switch is accessed.

To access managed PCs, you must run the client. We were unable to run the Windows Client on Windows 7 64-bit; in this case, the Java client, which runs on any platform with Java support, helps out. Already at the client we can produce more fine tuning devices:

To navigate to managed devices, use the tab Main, which displays all client modules connected to the switch (or chain of switches):

At correct setting data transfer speeds work through remote client quite comfortable, the only drawback is some (sometimes significant) lag of the mouse cursor on the remote system from the cursor on the control PC.

However, it should be remembered that working via KVM Over IP is required mostly in emergency situations when control at the PC load level is required; in other cases it will be much more comfortable to work via RDP. If you are using a USB module (KA9570), make sure that the USB support keyboard and mouse to avoid unpleasant surprises.

We also recommend that you configure the server BIOS to turn on a signal from the keyboard or via the network. This will allow you to turn on the server remotely if you suddenly turn it off by mistake or one of your overzealous employees turns it off.

KVM over IP switches allow the administrator to gain almost complete control over the managed PC from anywhere in the world, provided there is Internet access. And the seemingly relatively high price of the device at first glance is more than compensated by the capabilities it provides. In any case, it is worth calculating what will cost less, a KVM IP switch or the downtime of the enterprise required for the arrival of a technician.