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Qemu

Kernel configuration

        # usermod -a -G kvm c9admin
        # usermod -a -G kvm username

Create hard disk image, there is different types, this describes how to create a qcow2 type;

        $ qemu-img create -f qcow2 crux-img.qcow2 20G

You can mount disk image;

        $ sudo modprobe nbd
        $ sudo qemu-nbd -c /dev/nbd0 /crux-img.qcow2

To disconnect image disk (ndb);

        $ sudo qemu-nbd -d /dev/nbd0

You can use image as a normal disk, example how to use parted to create a gpt system table;

        # parted /dev/nbd0
        (parted) mklabel gpt

More information about gpt partition table.

If partitions are on qcow2 image then setup partitions;

        # kpartx -a -s -l /dev/nbd0

Network configuration;

        KERNEL=="tun", GROUP="kvm", MODE="0660", OPTIONS+="static_node=net/tun"

Automatic creation of tap interface with correct permissions set for user and group, you can set only user or group;

        # tunctl -u username -g kvm

Set permissions to existing tap interface;

        # tunctl -u username -t tap0

Manual creation of tap interface;

	# ip tuntap add name tap0 mode tap
        # chmod 0666 /dev/tap0
        # chown root:username /dev/tap0
	# ip link show

Start qemu with 512 of ram, mydisk.img as disk and boot from iso

        $ qemu-system-x86_64 \
        -enable-kvm \
        -m 512 \
        -boot d -cdrom image.iso \
        -hda mydisk.img

Start qemu with 1024 of ram, network configured using tap0 interface device no host and boot from crux.qcow2;

	$ qemu-system-x86_64 \
	-enable-kvm \
	-m 1024 \
	-hda c9/local/crux.qcow2 \
	-net nic,model=virtio -net tap,ifname=tap0,script=no,downscript=no

On host machine test network;

	# tcpdump tap0

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