How to use the command `virsh-connect` (with examples)
The virsh-connect command is used to connect to a virtual machine hypervisor. It allows users to interact with different hypervisors and perform various management tasks on virtual machines.
Use case 1: Connect to the default hypervisor
Code:
virsh connect
Motivation: This command is used to connect to the default hypervisor. The default hypervisor is the one that is configured as the default connection in the virsh program.
Explanation: When executed without any arguments, the virsh connect command connects to the default hypervisor. This is useful when you only have one hypervisor and want to establish a connection quickly.
Example output:
Connected to domain hypervisor
Use case 2: Connect as root to the local QEMU/KVM hypervisor
Code:
virsh connect qemu:///system
Motivation: This command is used to connect to the local QEMU/KVM hypervisor as the root user. By connecting as the root user, you have full administrative privileges to manage virtual machines on the hypervisor.
Explanation: The argument qemu:///system is used to specify the URI of the local QEMU/KVM hypervisor. The qemu protocol denotes the type of hypervisor, while system specifies that it is the system-wide hypervisor.
Example output:
Connected to QEMU/KVM hypervisor on localhost as root
Use case 3: Launch a new instance of the hypervisor and connect to it as the local user
Code:
virsh connect qemu:///session
Motivation: This command is used to launch a new instance of the hypervisor and connect to it as the local user. By launching a new instance, you can have a separate session to manage virtual machines without interfering with the system-wide hypervisor.
Explanation: The argument qemu:///session is used to specify the URI of the new instance of the hypervisor. The qemu protocol denotes the type of hypervisor, while session specifies that it is a separate session for the local user.
Example output:
Connected to a new instance of the QEMU/KVM hypervisor as the local user
Use case 4: Connect as root to a remote hypervisor using ssh
Code:
virsh connect qemu+ssh://user_name@host_name/system
Motivation: This command is used to connect as the root user to a remote hypervisor using ssh. By connecting remotely, you can manage virtual machines on a different machine or network.
Explanation: The argument qemu+ssh://user_name@host_name/system is used to specify the URI of the remote hypervisor. The qemu+ssh protocol denotes that the connection will be made using ssh. user_name should be replaced with the username to authenticate with on the remote machine, and host_name should be replaced with the IP address or hostname of the remote machine. The system specifies that it is the system-wide hypervisor on the remote machine.
Example output:
Connected to QEMU/KVM hypervisor on remote machine as root via ssh
Conclusion:
The virsh-connect command is a versatile tool for connecting to virtual machine hypervisors. Whether connecting to the default hypervisor, a local QEMU/KVM hypervisor, a new instance of the hypervisor, or a remote hypervisor, this command provides flexibility in managing virtual machines.
