** Description changed:
+ ### Title
+
+ Netplan fails to configure DHCP on first boot when installed with NIC
+ disabled then enabled
+
+ ---
+
### Description
When installing Ubuntu (versions 26.04 and 26.10) inside a Virtual
Machine with the Network Interface Card (NIC) disabled during
installation, powering off the VM, cloning it, and subsequently turning
on the NIC in the clone results in a system where internet connectivity
- does not initialize automatically at boot.
+ does not initialize automatically at boot because Subiquity generates a
+ hardware-tied configuration:
- In contrast, **Ubuntu MATE 26.10 handles this scenario correctly**, and
+ ```yaml
+ # This is the network config written by 'subiquity'
+ network:
+ ethernets:
+ enp1s0:
+ match:
+ macaddress: XX:XX:XX:XX:XX:XX
+ set-name: enp1s0
+ version: 2
+
+ ```
+
+ In contrast, Ubuntu MATE 26.10 handles this scenario correctly and
internet connectivity works out of the box when the NIC is enabled on
- the clone, even though its default configuration
- (`/etc/netplan/00-installer-config.yaml`) does not explicitly contain a
- `dhcp4` directive and looks like this:
+ the clone, even though its default configuration does not explicitly
+ contain a `dhcp4` directive and looks like this:
```yaml
# This is the network config written by 'subiquity'
network:
ethernets: {}
version: 2
```
---
### Steps to Reproduce
1. Create a Virtual Machine with the NIC disabled or disconnected.
2. Complete the installation of Ubuntu 26.04 or 26.10 inside the VM.
3. Power off the Virtual Machine and create a clone of it.
4. Enable the NIC on the cloned VM, then power it on.
5. Check if internet connectivity connects automatically at boot.
---
### Expected Result
Internet connectivity should connect automatically at boot once the NIC
is turned on in the cloned VM, consistent with the behavior observed in
Ubuntu MATE.
---
### Actual Result
Internet connectivity does not connect automatically at boot when booted
with the NIC enabled on standard Ubuntu installations.
---
### Additional Information / Workaround
Unlike standard Ubuntu, Ubuntu MATE 26.10 works seamlessly out of the
box regardless of whether the NIC was on or off during installation,
without requiring manual Netplan adjustments.
As a temporary workaround for standard Ubuntu installations, the
following script can be used to resolve the issue:
```bash
if grep -q '^ID=ubuntu' /etc/os-release && \
grep -q '^VERSION_ID="26\.' /etc/os-release && \
grep -Eq '^Ubuntu [0-9]' /var/log/installer/media-info 2>/dev/null; then
IFACE=$(ip -4 route show default | awk '{print $5}' | head -n1)
[ -z "$IFACE" ] && IFACE="enp1s0"
# Check if DHCP is already configured
DHCP4_SET=$(netplan get ethernets."$IFACE".dhcp4 2>/dev/null)
DHCP6_SET=$(netplan get ethernets."$IFACE".dhcp6 2>/dev/null)
if [ "$DHCP4_SET" != "true" ] || [ "$DHCP6_SET" != "true" ]; then
sudo netplan set ethernets."$IFACE".dhcp4=true
sudo netplan set ethernets."$IFACE".dhcp6=true
sudo netplan generate
sudo netplan apply
# Wait for WAN and DNS so premature apt runs don't fail InRelease
checks
until wget -q --spider --timeout=1 http://archive.ubuntu.com; do
sleep 1
done
fi
sudo apt-get update
fi
```
+
+ Applying this workaround updates `/etc/netplan/00-installer-config.yaml`
+ to the following structure:
+
+ ```yaml
+ network:
+ version: 2
+ ethernets:
+ enp1s0:
+ match:
+ macaddress: "XX:XX:XX:XX:XX:XX"
+ dhcp4: true
+ dhcp6: true
+ set-name: "enp1s0"
+
+ ```
** Description changed:
- ### Title
-
- Netplan fails to configure DHCP on first boot when installed with NIC
- disabled then enabled
-
- ---
-
### Description
When installing Ubuntu (versions 26.04 and 26.10) inside a Virtual
Machine with the Network Interface Card (NIC) disabled during
installation, powering off the VM, cloning it, and subsequently turning
on the NIC in the clone results in a system where internet connectivity
does not initialize automatically at boot because Subiquity generates a
hardware-tied configuration:
```yaml
# This is the network config written by 'subiquity'
network:
- ethernets:
- enp1s0:
- match:
- macaddress: XX:XX:XX:XX:XX:XX
- set-name: enp1s0
- version: 2
+ ethernets:
+ enp1s0:
+ match:
+ macaddress: XX:XX:XX:XX:XX:XX
+ set-name: enp1s0
+ version: 2
```
In contrast, Ubuntu MATE 26.10 handles this scenario correctly and
internet connectivity works out of the box when the NIC is enabled on
the clone, even though its default configuration does not explicitly
contain a `dhcp4` directive and looks like this:
```yaml
# This is the network config written by 'subiquity'
network:
- ethernets: {}
- version: 2
+ ethernets: {}
+ version: 2
```
---
### Steps to Reproduce
1. Create a Virtual Machine with the NIC disabled or disconnected.
2. Complete the installation of Ubuntu 26.04 or 26.10 inside the VM.
3. Power off the Virtual Machine and create a clone of it.
4. Enable the NIC on the cloned VM, then power it on.
5. Check if internet connectivity connects automatically at boot.
---
### Expected Result
Internet connectivity should connect automatically at boot once the NIC
is turned on in the cloned VM, consistent with the behavior observed in
Ubuntu MATE.
---
### Actual Result
Internet connectivity does not connect automatically at boot when booted
with the NIC enabled on standard Ubuntu installations.
---
### Additional Information / Workaround
Unlike standard Ubuntu, Ubuntu MATE 26.10 works seamlessly out of the
box regardless of whether the NIC was on or off during installation,
without requiring manual Netplan adjustments.
As a temporary workaround for standard Ubuntu installations, the
following script can be used to resolve the issue:
```bash
if grep -q '^ID=ubuntu' /etc/os-release && \
- grep -q '^VERSION_ID="26\.' /etc/os-release && \
- grep -Eq '^Ubuntu [0-9]' /var/log/installer/media-info 2>/dev/null; then
- IFACE=$(ip -4 route show default | awk '{print $5}' | head -n1)
- [ -z "$IFACE" ] && IFACE="enp1s0"
+ grep -q '^VERSION_ID="26\.' /etc/os-release && \
+ grep -Eq '^Ubuntu [0-9]' /var/log/installer/media-info 2>/dev/null; then
+ IFACE=$(ip -4 route show default | awk '{print $5}' | head -n1)
+ [ -z "$IFACE" ] && IFACE="enp1s0"
- # Check if DHCP is already configured
- DHCP4_SET=$(netplan get ethernets."$IFACE".dhcp4 2>/dev/null)
- DHCP6_SET=$(netplan get ethernets."$IFACE".dhcp6 2>/dev/null)
+ # Check if DHCP is already configured
+ DHCP4_SET=$(netplan get ethernets."$IFACE".dhcp4 2>/dev/null)
+ DHCP6_SET=$(netplan get ethernets."$IFACE".dhcp6 2>/dev/null)
- if [ "$DHCP4_SET" != "true" ] || [ "$DHCP6_SET" != "true" ]; then
- sudo netplan set ethernets."$IFACE".dhcp4=true
- sudo netplan set ethernets."$IFACE".dhcp6=true
- sudo netplan generate
- sudo netplan apply
+ if [ "$DHCP4_SET" != "true" ] || [ "$DHCP6_SET" != "true" ]; then
+ sudo netplan set ethernets."$IFACE".dhcp4=true
+ sudo netplan set ethernets."$IFACE".dhcp6=true
+ sudo netplan generate
+ sudo netplan apply
- # Wait for WAN and DNS so premature apt runs don't fail InRelease
checks
- until wget -q --spider --timeout=1 http://archive.ubuntu.com; do
- sleep 1
- done
- fi
+ # Wait for WAN and DNS so premature apt runs don't fail InRelease
checks
+ until wget -q --spider --timeout=1 http://archive.ubuntu.com; do
+ sleep 1
+ done
+ fi
- sudo apt-get update
+ sudo apt-get update
fi
```
Applying this workaround updates `/etc/netplan/00-installer-config.yaml`
to the following structure:
```yaml
network:
- version: 2
- ethernets:
- enp1s0:
- match:
- macaddress: "XX:XX:XX:XX:XX:XX"
- dhcp4: true
- dhcp6: true
- set-name: "enp1s0"
+ version: 2
+ ethernets:
+ enp1s0:
+ match:
+ macaddress: "XX:XX:XX:XX:XX:XX"
+ dhcp4: true
+ dhcp6: true
+ set-name: "enp1s0"
```
+
+ Note to triage team: Please consider setting Importance to High, as this
+ defect impacts all users and automated testing pipelines performing
+ default ISO installations with the NIC intentionally disabled to prevent
+ unwanted automatic background package downloads during setup.
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https://bugs.launchpad.net/bugs/2170258
Title:
Netplan fails to configure DHCP on first boot when installed with NIC
disabled then enabled
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