We can help you quickly fix “/dev/kvm does not exist” in the GNS3 issue with this article. At Bobcares, with our Server Management Service, we can handle the KVM issues.

“/dev/kvm does not exist” in GNS3: Fix

When using GNS3, the error message “/dev/kvm does not exist” usually indicates a problem with the virtualization setup or permissions. Here are some methods we can take to troubleshoot and remedy the issue:

1. Examine Virtualization Support: Check to see if the CPU supports hardware virtualization and if it is enabled in the BIOS settings. In BIOS, the virtualization capability may be referred to as “Intel VT-x” for Intel CPUs or “AMD-V” for AMD processors. For information on activating virtualization, check the computer’s documentation or the manufacturer’s website.

2. Check Kernel Modules: The Kernel-based VM module creates the “/dev/kvm” device. Ensure that the required modules are loaded into the kernel. We can verify this by entering the following code:

lsmod | grep kvm

If there is no output, it signifies that the modules have not been loaded. In that case, try manually loading them using the following codes:

sudo modprobe kvm sudo modprobe kvm_intel # For Intel processors sudo modprobe kvm_amd # For AMD processors

If the above commands fail, it may be due to the absence of KVM on the machine. So, set up it with the package manager for Linux. On Ubuntu, for example, perform the command:

sudo apt-get install qemu-kvm

3. Check User Permissions: In order to access the “/dev/kvm” device, GNS3 requires suitable permissions. Check that the user account belongs to the “kvm” group. We can verify this by entering the following command:

groups

Also, look for the word “kvm” in the output. If it isn’t already there, We can add ourselves to the “kvm” group with the following command:

sudo usermod -aG kvm $(whoami)

Then, log out and back in after adding us to the group for the changes to take effect.

4. Restart GNS3 and Check Settings: Finally, restart GNS3 and try again if we made any changes to the setup or permissions. Also, ensure that GNS3 is set to use KVM as the virtualization engine. In GNS3, go to “Edit” >> “Preferences,” choose “VirtualBox” under “Compute,” and check “QEMU VMs.” Then, under the “QEMU VMs” page, select “KVM” as the hypervisor.

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Conclusion

The article provides a simple 5-step method to fix the “/dev/kvm does not exist” in the GNS3 issue. If we follow these steps, we should be able to overcome the error in GNS3 and successfully use the KVM virtualization engine.