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Redirect FreeBSD Console To A Serial Port for KVM Virsh - How to do it

This article covers how to redirect FreeBSD in KVM to the serial port.

FreeBSD does support a dumb terminal on a serial port as a console.


This is useful for quick login or debug guest system problem without using ssh. 

1. First, login as root using ssh to your guest operating systems:

$ ssh ibmimedia@freebsd.ibmimedia.com

su -

2. Edit /boot/loader.conf, enter:

# vi /boot/loader.conf

3. Append the following entry:

console="comconsole"

4. Save and close the file. Edit /etc/ttys, enter:

# vi /etc/ttys

5. Find the line that read as follows:

ttyd0  "/usr/libexec/getty std.9600"   dialup  off secure

6. Update it as follows:

ttyd0   "/usr/libexec/getty std.9600"   vt100   on secure

7. Save and close the file. Reboot the guest, enter:

# reboot

8. After reboot, you can connect to FreeBSD guest as follows from host (first guest the list of running guest operating systems):

# virsh list

Sample outputs:


 Id Name                 State

----------------------------------

  3 ographics            running

  4 freebsd              running

9. Now, connect to Freebsd guest, enter:

virsh console 4

OR

virsh console freebsd

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Troubleshoot KVM Virtualization Problem

This article covers how to troubleshoot KVM virtualization problem.


Log file locations and tools used to track down #KVM #problems are:
1. $HOME/.virtinst/virt-install.log – virt-install tool log file.
2. $HOME/.virt-manager/virt-manager.log – virt-manager tool log file.
3. /var/log/libvirt/qemu/ – Log files for each running virtual machine. If centos is virtual machine name, than log file is /var/log/libvirt/qemu/centos.log.

You can use the grep and other Linux tools to view this files:
# tail -f /var/log/libvirt/qemu/freebsd.log
# grep something $HOME/.virtinst/virt-install.log
$ sudo tail -f /var/log/libvirt/qemu/openbsd.log

Hyper-V backups can fail for any number of reasons, but there are some things to look for when backups don’t work the way that they are supposed to.
When backups fail, the first thing that you should do is to check the backup logs in an effort to learn more about the problem.
Specifically, you need to determine if the problem is confined to a particular host, a particular virtual machine, or perhaps related to the backup target itself.

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Manage KVM guest virtual machines via virsh commands

This article will guide you on how to use to manage KVM guest virtual #machines using virsh #commands.

virsh is a command line utility for managing virsh guest domains/virtual machines and the #hypervisor.

Linux list a KVM vm guest using #virsh command.

The main command interface used to control both Solaris xVM and guest domains is the virsh command. virsh provides a generic and stable interface for controlling virtualized operating systems.

Many virsh commands act asynchronously. This means that the system prompt can return before the operation has completed.

#KVM lets you turn Linux into a hypervisor that allows a host machine to run multiple, isolated virtual environments called guests or virtual machines (VMs).

To log into VM with Virsh, simply:

1. Open a shell prompt or login using ssh. 

2. Login to a host server called server1. 

3. Use the virsh console command to log in to a running VM called 'centos7' type: virsh console centos7.

The virsh destroy #command initiates an immediate ungraceful shutdown and stops the specified guest virtual machine. 

Using virsh destroy can corrupt guest virtual machine file systems. 

Use the virsh destroy command only when the guest virtual machine is unresponsive.

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