KVM (Keyboard, Video, Mouse) is a switch or hardware device allows a single keyboard, video monitor and mouse to control more than one server one at a time. KVM can be local device or remote device working over IP network. KVM devices extensively used in server farms where it is only necessary to periodically access box. KVM allows you to access your server even if a remote public network connectivity is down.
- Troubleshoot problems
- Install Linux / *BSD remotely
- Access BIOS and change settings remotely
- Access the server even if network is down
- Access the server even if it is very busy or has stopped responding to network connections.
- Reset root password
- Run fsck and lots of other stuff
KVM over IP
KVM over IP devices are typically connected to a system’s standby power plane so that you can see entire boot process or access BIOS. They work over TCP/IP. You can access your server using a web browser or standalone client application provided by vendor.
With this technology you can control entire server rack from the office, or around the world. Most KVM switch integrates KVM and serial devices into a single management console for all your servers, network devices and infrastructure.
Today you don’t have to put external KVM devices hanging off the back of the server rack. You need to just insert add-on card (daughtercards) to enable KVM support.
--------------+ | Server Rack | +-------------+ | Server 1 | ===> VPN Router | Server 2 | | Server 3 | ---> Public Router | Server N | | KVM Switch | +-------------+
To manage server you need to connect server via VPN client. Once logged in you can access each server using KVM even if public network is down. Public router allows rest of the world access your web or mail server but not KVM device.
KVM in Action
First, connect to your backend network using VPN client.
Once connected open KVM application supplied by your vendor. Following is application supplied by Supermicro vendor
(Fig. 01: Login Screen – Click to enlarge image)
I hope this small post gives out introductory information about KVM over IP. For further information please consult following resources. I think KVM will be standard feature on the motherboard in coming days. Tomorrow, I will write about “Intelligent Platform Management Interface” (IPMI) technology developed by Intel and others.
- KVM switch – From Wikipedia, the free encyclopedia
- KVM Over IP: A New Approach to Server Management – Another excellent article from Dell.
- HP Server Console Switches – KVM over CAT5
- Supermicro Intelligent Management – KVM add-on card products – Many of our server powered by these cards.
|Category||List of Unix and Linux commands|
|Firewall||Alpine Awall • CentOS 8 • OpenSUSE • RHEL 8 • Ubuntu 16.04 • Ubuntu 18.04 • Ubuntu 20.04|
|Network Utilities||dig • host • ip • nmap|
|OpenVPN||CentOS 7 • CentOS 8 • Debian 10 • Debian 8/9 • Ubuntu 18.04 • Ubuntu 20.04|
|Package Manager||apk • apt|
|Processes Management||bg • chroot • cron • disown • fg • jobs • killall • kill • pidof • pstree • pwdx • time|
|Searching||grep • whereis • which|
|User Information||groups • id • lastcomm • last • lid/libuser-lid • logname • members • users • whoami • who • w|
|WireGuard VPN||CentOS 8 • Debian 10 • Firewall • Ubuntu 20.04|