Ubuntu Vm Images -

| Component | Desktop Default | Cloud Image Default | |-----------|----------------|----------------------| | Root password | Set by user | Locked ( * in shadow) | | SSH | Not installed | Installed and enabled | | Password auth | Allowed | Disabled (key-only) | | Firewall | None (ufw inactive) | None (cloud security groups handle isolation) | | Automatic updates | Unattended-upgrades off | Unattended-upgrades on (security updates only) | | Kernel livepatch | Off | Available via UA subscription |

: unattended-upgrades on first boot can cause race conditions with cloud-init and configuration management (Puppet, Ansible). Many production users disable it and rebuild images weekly. 5. Building Custom Images: The Modern Toolchain While downloading official images is common, enterprises need golden images with pre-installed agents (Datadog, CrowdStrike), custom kernels, or compliance tooling. 5.1 packer (HashiCorp) – The Industry Standard source "qemu" "ubuntu" iso_url = "https://releases.ubuntu.com/22.04/ubuntu-22.04-live-server-amd64.iso" http_directory = "http" boot_command = [ "<esc><wait>", "set autoinstall<wait>", "curl -s http:// .HTTPIP : .HTTPPort /user-data > /tmp/user-data<enter>" ] ssh_username = "ubuntu" qemu_binary = "/usr/bin/qemu-system-x86_64" ubuntu vm images

| Format | Primary Use Case | Key Characteristics | |--------|------------------|----------------------| | ( .qcow2 ) | OpenStack, KVM, Proxmox | No graphical installer; uses cloud-init ; minimal package set; optimized for first-boot configuration | | Cloud Images ( .img ) | AWS, GCP, Azure (after conversion) | Raw format with partition table; requires cloud-specific agents (e.g., waagent for Azure) | | Vagrant Boxes ( box file) | Development (VirtualBox, libvirt) | Includes VirtualBox Guest Additions or virtio drivers; user vagrant with insecure key; shared folder support | | OVA/OVF | vSphere, ESXi | VMX descriptor + VMDK disk; typically pre-configured for VMware paravirtual SCSI and vmxnet3 | | Live Server ISO | Manual interactive install | Contains debian-installer or Subiquity; not a VM image per se but can generate one post-install | | Component | Desktop Default | Cloud Image