Virtualization

Build Isolated KVM Lab Networks

Define application and database-only libvirt networks; Assign deterministic DHCP identities where required; Prove allowed east-west traffic; Prove the database segment has no unintended WAN route.

By InventiveHQ Team

Episode 14 of the InventiveHQ KVM virtualization series.

Lab verified July 2026 · Ubuntu 26.04 · libvirt 12.0.0 · QEMU 10.2.1

What this episode proves

  • Define application and database-only libvirt networks
  • Assign deterministic DHCP identities where required
  • Prove allowed east-west traffic
  • Prove the database segment has no unintended WAN route

Validated workflow

1. Define application and database-only libvirt networks

virsh net-define app-net.xml

2. Assign deterministic DHCP identities where required

virsh net-define db-net.xml

3. Prove allowed east-west traffic

virsh net-autostart app-net

4. Prove the database segment has no unintended WAN route

ping -I 192.168.170.10 -c 3 1.1.1.1

Finished state

Autostarting app-net and db-net definitions are available for later automation lessons. The public scripts contain no private keys, passwords, or tokens. Review names, addresses, paths, ownership, backups, quorum, and fencing for your own environment before running them.

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