Use Guestfish to Reset the Forgotten Root Password for the

This updated guide examines Use Guestfish to Reset the Forgotten Root Password for the and organizes the essential facts, background, and practical takeaways in clear American English.

Responsible-use note: Apply security techniques only to systems you own or are explicitly authorized to test.

Prepare LAB lesson

• On a VMware environment, use a CentOS 7 virtual machine with KVM installed.
• Create a CentOS 7.0 virtual machine with qcow2 format

Proceed to set the root password

Step 1: Install Guestfish

yum install libguestfs-tools -y

Step 2: Shutdown the virtual machine

virsh shutdown tên_máy_?o

Step 3: Reset, change the root password using Guestfish

Note: First create a new root user password by typing the following command and then using the encrypted password to change.

openssl passwd -1 pass_m?i

Then run the following command, for the Centos7 virtual machine:

guestfish --rw -a /var/lib/libvirt/images/centos7.0.qcow2

Next use the following commands

> launch > list-filesystems #li?t kê các phân vùng /dev/sda1: xfs /dev/centos/root: xfs /dev/centos/swap: swap > mount /dev/centos/root / #l?u ý l?a ch?n mount vào phân vùng c?a h? th?ng có ch?a th? m?c /etc. > vi /etc/shadow #ch?nh s?a file shadow

For example: The same for ubuntu virtual machines

After running the vi / etc / shadow command, fix the encrypted pass at root with the new encrypted pass from the openssl command above and save it:

Then exit Guestfish:

> quit

Step 4: Open the virtual machine with virt-manager and enter the new password

So you have finished resetting the forgotten root password for the virtual machine in qcow2 format on KVM.