4. Images should contain cloud-init, qemu-guest-agent and grow-part tools
5. OpenStack will resize instance after start. Image shouldn't contain any empty partitions or free space
## Add SWAP file to instance
By default VMs after creation do not have SWAP partition. If you need to add a SWAP file to your system you can download and run [script](https://gitlab.ics.muni.cz/cloud/cloud-tools/blob/master/swap.sh) that create SWAP file on your VM.