<vcpu placement='static'>4</vcpu> <cputune> <vcpupin vcpu='0' cpuset='2'/> <vcpupin vcpu='1' cpuset='3'/> </cputune> Without pinning, vCPUs float across cores, thrashing L2/L3 caches. Balloon driver ( virtio_balloon ) allows host to reclaim unused guest memory. However, it adds latency. For databases or real-time apps, disable ballooning and set memoryBacking to locked :
Packer launches a VM, runs an autoinstall (Ubuntu's new declarative installer), provisions with shell/Ansible, and outputs QCOW2, VMDK, or raw. Generate a fake metadata disk: ubuntu vm images
cloud-localds seed.iso user-data meta-data # Attach seed.iso as a CDROM to the VM This allows testing cloud-init behavior without a real metadata service. For quick fixes without booting the VM: vcpupin vcpu='0' cpuset='2'/>