1. Overview Subject File: Csr1000v-ucmk9.16.12.1b-serial.qcow2 Target Action: Repack (Modify → Rebuild → Recompress) Original Purpose: Cisco Cloud Services Router 1000v (CSR1000v) QCOW2 disk image for KVM/QEMU, version 16.12.1b, Universal image with Strong Crypto (ucmk9), pre-provisioned with a serial-based license.
Repacking refers to the process of extracting, modifying contents (e.g., embedded configuration, software, license triggers, or disk structure), and rebuilding the QCOW2 image while preserving boot functionality. | Attribute | Value | |-----------|-------| | Format | QCOW2 (QEMU Copy-On-Write v2) | | Virtual Size | ~8 GB typical | | Actual Size (compressed) | Varies (original ~2–3 GB) | | Guest OS | IOS-XE (Linux + IOSd) | | Filesystem | ext4 + partitions (boot, rootfs, etc.) | | Bootloader | GRUB (BIOS) | | Serial-license marker | Embedded in /boot/ or config partition |
guestfish -a temp.qcow2 -i <<EOF write /etc/hostname "repacked-router" write /boot/license/license.lic "CISCO_LICENSE: ABC123XYZ" EOF Csr1000v-ucmk9.16.12.1b-serial.qcow2 REPACK
qemu-img convert -f qcow2 -O qcow2 -c temp.qcow2 "$DST" rm temp.qcow2 echo "Repacked: $DST" Cisco images are proprietary. Repacking may violate the End User License Agreement (EULA) if used to bypass licensing or redistribute modified images. Authorized use cases include internal lab testing, training, and authorized engineering modifications with valid support contracts. 9. Conclusion Repacking Csr1000v-ucmk9.16.12.1b-serial.qcow2 is technically straightforward using standard Linux tools ( qemu-img , libguestfs ). The process enables customization, automation, and optimization of CSR1000v deployments. However, operators must respect licensing terms and verify boot integrity post-repack.
sudo mkdir /mnt/csr_root sudo guestmount -a working.qcow2 -m /dev/sda2 /mnt/csr_root sudo guestmount -a working.qcow2 -m /dev/sda1 /mnt/csr_root/boot # separate boot | Attribute | Value | |-----------|-------| | Format
Typical output:
Csr1000v-REPACK.qcow2 – functional, customized, ready for deployment in non-production environments. libguestfs ). The process enables customization
/dev/sda1: ext4 (boot) /dev/sda2: ext4 (rootfs) /dev/sda3: swap Using guestmount (libguestfs):