Introduction

Create a Single VM

Download Script

curl -sSL -o oneqemu.sh https://raw.githubusercontent.com/oneclickvirt/qemu/main/scripts/oneqemu.sh
chmod +x oneqemu.sh

Usage

./oneqemu.sh <name> <cpu> <memory_mb> <disk_gb> <password> <sshport> <startport> <endport> [system]
./oneqemu.sh <name> <cpu> <memory_mb> <disk_gb> <password> <sshport> <startport> <endport> <extra_flag(y/n)> [system]

Argument	Description	Default
name	VM name	vm1
cpu	CPU cores	1
memory_mb	Memory in MB	1024
disk_gb	Disk size in GB	20
password	Root password	generated
sshport	SSH host port	25001
startport	First additional port	35001
endport	Last additional port	35025
system	Guest OS in position 9 or 10	debian

System	Supported versions	Examples
debian	10, 11, 12, 13	debian, debian12, debian13
ubuntu	18, 20, 22, 24	ubuntu, ubuntu22, ubuntu24
almalinux	8, 9	almalinux9, alma9
rockylinux	8, 9	rockylinux9, rocky9
openeuler	22	openeuler

System names are case-insensitive and accept separators such as debian-13 and ubuntu_22.

Environment variables are also accepted; positional arguments take precedence:

export noninteractive=true
export VM_NAME=vm1
export VM_CPU=1
export VM_MEMORY=1024
export VM_DISK=20
export VM_PASSWORD='ChangeMe-123'
export VM_SSH_PORT=25001
export VM_START_PORT=35001
export VM_END_PORT=35025
export VM_SYSTEM=debian12
./oneqemu.sh

Example

Choose one of the following examples:

./oneqemu.sh vm1 1 1024 20 MyPassword 25001 35001 35025 debian
# Optional flag in position 9, system in position 10:
./oneqemu.sh vm1 1 1024 10 MyPassword 25000 34975 35000 n debian13

Related Operations

virsh list --all
virsh console <name>     # Exit with Ctrl+]
virsh start <name>
virsh shutdown <name>
virsh destroy <name>     # Force power off
virsh reboot <name>
virsh dominfo <name>
virsh domifaddr <name>

Project management script:

curl -sSL -o manage_qemu.sh https://raw.githubusercontent.com/oneclickvirt/qemu/main/scripts/manage_qemu.sh
chmod +x manage_qemu.sh
./manage_qemu.sh info all
./manage_qemu.sh info vm1
./manage_qemu.sh snapshot vm1 before-upgrade
./manage_qemu.sh set-resources vm1 2 2048

info includes vmlog, VM state, MAC address, IPs and ports. set-resources takes CPU cores and memory in MB.

Batch Create VMs

Run

curl -sSL -o create_qemu.sh https://raw.githubusercontent.com/oneclickvirt/qemu/main/scripts/create_qemu.sh
chmod +x create_qemu.sh
./create_qemu.sh

The interactive script increments VM names, SSH ports and public ports, and writes vmlog. A batch lock serializes creation. A failed VM stops subsequent creation so names and port assignments do not continue drifting.

Command-line configuration:

# ./create_qemu.sh <count> <memory_mb> <cpu> <disk_gb> <system>
./create_qemu.sh 3 1024 1 20 debian12

Unattended environment configuration:

export noninteractive=true
export VM_COUNT=3
export VM_MEMORY=1024
export VM_CPU=1
export VM_DISK=20
export VM_SYSTEM=debian12
./create_qemu.sh

Creation does not block on cloud-init completion. DHCP reservations and forwarding rules are installed before startup; cloud-init continues in the running guest. Connect once SSH is ready. Monitor initialization with:

tail -f /tmp/qemu-init-vm1.*.log

Query Batch Creation Info

Connection information is saved in /root/vmlog. View it with:

cat /root/vmlog

Delete one VM

curl -sSL -o delete_qemu.sh https://raw.githubusercontent.com/oneclickvirt/qemu/main/scripts/delete_qemu.sh
chmod +x delete_qemu.sh
./delete_qemu.sh <vm_name>
./delete_qemu.sh vm1 -y

Unattended environment configuration:

export VM_NAME=vm1
export noninteractive=true
export QEMU_FORCE_DELETE=yes
./delete_qemu.sh

Deletion removes the VM definition, disks, DHCP reservation, nftables/iptables forwarding rules and connection records. Successful deletion updates both /root/vmlog and the local SQLite state database.

Delete multiple VMs

Use the deletion script for each confirmed VM name so DHCP reservations, forwarding rules, vmlog and SQLite state are also cleaned up:

for vm in vm1 vm2; do
  ./delete_qemu.sh "$vm" -y || break
done

To remove the complete environment and all VM disks, use the uninstaller in the installation guide.

Restart All VMs After Host Reboot

QEMU/KVM supports setting VMs to autostart via libvirt:

# Enable autostart for a specific VM
virsh autostart vm1

# Check autostart status
virsh dominfo vm1 | grep Autostart

# Disable autostart
virsh autostart vm1 --disable

Or manually start all stopped VMs:

for vm in $(virsh list --all --name); do virsh start "$vm" 2>/dev/null; done

See networking, images and troubleshooting for network modes, image sources and records.