Snapshot Restore Breaks Static IP on Ubuntu 22.04

When This Happens

You’re running Ubuntu 22.04 LTS on a VM — maybe Proxmox, VMware, or KVM. You set a static IP in /etc/netplan/00-installer-config.yaml back when you built the box. Months later, you roll back to an earlier snapshot (maybe to test a patch, maybe you broke something and need a clean state). After the revert, the VM boots, but you can’t SSH in. You console in and ip a shows a DHCP lease on a different subnet, or worse, no IP at all. Your static config file is still there. But the system ignored it.

What’s actually happening here is a silent fight between Netplan and the cloud-init or systemd-networkd fallback that gets triggered during the revert. The snapshot keeps the files, but the boot order re-evaluates the renderer — and it picks the wrong one.

Why It Breaks

Netplan on Ubuntu 22.04 uses a renderer — either NetworkManager or systemd-networkd. The default for server installs is systemd-networkd. But here’s the trap: when you take a snapshot, the renderer setting is stored in /etc/netplan/*.yaml. The restore keeps that file. But the actual systemd-networkd or NetworkManager service state (enabled/disabled, cached config) gets reset to whatever the snapshot’s boot state had.

If your snapshot was taken before the first boot completed (like a template snapshot), the renderer might have defaulted to NetworkManager during that first boot, or the netplan apply never ran cleanly. After revert, systemd-networkd might not be running, or it loads a stale fallback config. The fix is to force the renderer explicitly and regenerate the netplan config so it sticks.

The Fix – Step by Step

1. Check the current renderer. Run netplan get renderer. If it says NetworkManager and you’re on a server, that’s the problem. Server images should use systemd-networkd.
2. Kill any leftover NetworkManager. sudo systemctl stop NetworkManager; sudo systemctl disable NetworkManager. This stops it from grabbing interfaces back.
3. Force the renderer in your YAML file. Edit /etc/netplan/00-installer-config.yaml. At the top, add renderer: networkd under the network: line. Your file should look like:
   

   network:
     version: 2
     renderer: networkd
     ethernets:
       ens18:
         dhcp4: no
         addresses:
           - 192.168.1.100/24
         gateway4: 192.168.1.1
         nameservers:
           addresses: [8.8.8.8, 8.8.4.4]

4. Remove any other YAML files. Check /etc/netplan/ for extra files like 01-netcfg.yaml or 99-custom.yaml. Delete them or move them to a backup folder. Netplan merges all YAML files alphabetically, and a stray file can override your static config.
5. Apply the config. sudo netplan apply. Then run sudo netplan try and wait 120 seconds. If you lose SSH, the try will revert. You’ll confirm manually.
6. Enable systemd-networkd. sudo systemctl enable systemd-networkd; sudo systemctl restart systemd-networkd. Then check ip a — your static IP should be back.

Still Fails? Check This

If the IP still doesn’t come up after step 6, the problem is likely a cloud-init override. Cloud-init runs on first boot and can rewrite netplan configs. Snapshots that were taken before cloud-init finished will get hit. Fix it by disabling cloud-init network config: create /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the line network: {config: disabled}. Then reboot. Cloud-init will stop touching your netplan files entirely.

Another edge case: if you’re using network-manager intentionally (like on a desktop install), reverse the renderer to NetworkManager and enable that service instead. But for servers: stick with systemd-networkd. It’s simpler and doesn’t fight snapshots.

Pro tip: Before taking production snapshots, run sudo netplan get and save the output. After restore, compare. Saves you 20 minutes of head-scratching.