Reproducer with DHCP server/client on LXD. [Focal]
Bridge
---
sudo ip link add focalbr type bridge
sudo ip link set focalbr up
LXD container for DHCP server with classless static routes option
---
lxc init ubuntu:focal focal-dhcpd
lxc config device add focal-dhcpd eth0 nic nictype=bridged
parent=focalbr
lxc config device add focal-dhcpd eth1 nic nictype=bridged parent=lxdbr0
lxc start focal-dhcpd
lxc shell focal-dhcpd
dhclient eth1
...
ip addr add 10.11.12.13/24 dev eth0
apt install -y isc-dhcp-server
echo 'INTERFACESv4="eth0"' >>/etc/default/isc-dhcp-server
cat <<EOF >>/etc/dhcp/dhcpd.conf
option rfc3442-classless-static-routes code 121 = array of integer 8;
subnet 10.11.12.0 netmask 255.255.255.0 {
range 10.11.12.100 10.11.12.110;
option routers 10.11.12.13;
option rfc3442-classless-static-routes
0, 10, 11, 12, 200,
8, 1, 10, 11, 12, 208,
16, 2, 1, 10, 11, 12, 216,
24, 3, 2, 1, 10, 11, 12, 224,
32, 4, 3, 2, 1, 10, 11, 12, 232;
}
EOF
systemctl restart isc-dhcp-server.service
LXD VM for DHCP client
---
lxc init ubuntu:focal focal-dhclient --vm
lxc config device add focal-dhclient eth0 nic nictype=bridged
parent=focalbr
# no regular lxdbr0 bridge / internet access.
lxc start focal-dhclient
lxc shell focal-dhclient
# ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp5s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP
mode DEFAULT group default qlen 1000
link/ether 00:16:3e:36:6b:c8 brd ff:ff:ff:ff:ff:ff
# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp5s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP
group default qlen 1000
link/ether 00:16:3e:36:6b:c8 brd ff:ff:ff:ff:ff:ff
inet 10.11.12.101/24 brd 10.11.12.255 scope global dynamic enp5s0
valid_lft 582sec preferred_lft 582sec
inet6 fe80::216:3eff:fe36:6bc8/64 scope link
valid_lft forever preferred_lft forever
# ip route
default via 10.11.12.200 dev enp5s0 proto dhcp src 10.11.12.101 metric
100
1.0.0.0/8 via 10.11.12.208 dev enp5s0 proto dhcp src 10.11.12.101
metric 100
2.1.0.0/16 via 10.11.12.216 dev enp5s0 proto dhcp src 10.11.12.101
metric 100
3.2.1.0/24 via 10.11.12.224 dev enp5s0 proto dhcp src 10.11.12.101
metric 100
4.3.2.1 via 10.11.12.232 dev enp5s0 proto dhcp src 10.11.12.101 metric
100
10.11.12.0/24 dev enp5s0 proto kernel scope link src 10.11.12.101
Ok, all good from booted system's perspective.
Let's check at initramfs time, manually.
The classless routes aren't added if you run dhclient at the current
version.
cat <<EOF >/etc/default/grub.d/99-grub-initrd.cfg
GRUB_FORCE_PARTUUID=
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT console=ttyS0
break=bottom"
EOF
update-grub && poweroff
lxc start --console focal-dhclient
(initramfs) ip addr
1: lo: <LOOPBACK> mtu 65536 qdisc noop qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp5s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 1000
link/ether 00:16:3e:36:6b:c8 brd ff:ff:ff:ff:ff:ff
(initramfs) ip route
(initramfs)
(initramfs) dhclient enp5s0
sed: /etc/resolv.conf: No such file or directory
(initramfs) ip addr
1: lo: <LOOPBACK> mtu 65536 qdisc noop qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp5s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq qlen 1000
link/ether 00:16:3e:36:6b:c8 brd ff:ff:ff:ff:ff:ff
inet 10.11.12.102/24 brd 10.11.12.255 scope global enp5s0
valid_lft forever preferred_lft forever
inet6 fe80::216:3eff:fe36:6bc8/64 scope link
valid_lft forever preferred_lft forever
(initramfs) ip route
10.11.12.0/24 dev enp5s0 scope link src 10.11.12.102
(initramfs) dhclient -r enp5s0
(initramfs) exit
Test package (download it from dhcp server container)
---
@ focal-dhcpd:
add-apt-repository -y ppa:mfo/lp1926139
apt download isc-dhcp-client
python3 -m http.server
@ focal-dhclient:
wget 10.11.12.13:8000/isc-dhcp-client_4.4.1-2.1ubuntu5.20.04.5_amd64.deb
dpkg -i isc-dhcp-client_4.4.1-2.1ubuntu5.20.04.5_amd64.deb
Update the initramfs:
# lsinitramfs /boot/initrd.img-$(uname -r) | grep dhclient-exit-hooks.d
#
update-initramfs -u
# lsinitramfs /boot/initrd.img-$(uname -r) | grep dhclient-exit-hooks.d
etc/dhcp/dhclient-exit-hooks.d
etc/dhcp/dhclient-exit-hooks.d/rfc3442-classless-routes
# poweroff
Try again:
lxc start --console focal-dhclient
The classless routes ARE added if you run dhclient with the test
package.
(initramfs) ip addr
1: lo: <LOOPBACK> mtu 65536 qdisc noop qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp5s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 1000
link/ether 00:16:3e:36:6b:c8 brd ff:ff:ff:ff:ff:ff
(initramfs) ip route
(initramfs)
(initramfs) dhclient enp5s0
sed: /etc/resolv.conf: No such file or directory
(initramfs) ip addr
1: lo: <LOOPBACK> mtu 65536 qdisc noop qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp5s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq qlen 1000
link/ether 00:16:3e:36:6b:c8 brd ff:ff:ff:ff:ff:ff
inet 10.11.12.103/24 brd 10.11.12.255 scope global enp5s0
valid_lft forever preferred_lft forever
inet6 fe80::216:3eff:fe36:6bc8/64 scope link
valid_lft forever preferred_lft forever
(initramfs) ip route
default via 10.11.12.200 dev enp5s0
1.0.0.0/8 via 10.11.12.208 dev enp5s0
2.1.0.0/16 via 10.11.12.216 dev enp5s0
3.2.1.0/24 via 10.11.12.224 dev enp5s0
4.3.2.1 via 10.11.12.232 dev enp5s0
10.11.12.0/24 dev enp5s0 scope link src 10.11.12.103
(initramfs) dhclient -r enp5s0
(initramfs) exit
Now let's check that `ip=dhcp` is working (break=init stops after it
runs):
cat <<EOF >/etc/default/grub.d/99-grub-initrd.cfg
GRUB_FORCE_PARTUUID=
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT console=ttyS0
ip=dhcp break=init"
EOF
update-grub && poweroff
lxc start --console focal-dhclient
And yes, it is.
(initramfs) ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq qlen 1000
link/ether 00:16:3e:36:6b:c8 brd ff:ff:ff:ff:ff:ff
inet 10.11.12.104/24 brd 10.11.12.255 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::216:3eff:fe36:6bc8/64 scope link
valid_lft forever preferred_lft forever
(initramfs) ip route
default via 10.11.12.13 dev eth0
1.0.0.0/8 via 10.11.12.208 dev eth0
2.1.0.0/16 via 10.11.12.216 dev eth0
3.2.1.0/24 via 10.11.12.224 dev eth0
4.3.2.1 via 10.11.12.232 dev eth0
10.11.12.0/24 dev eth0 scope link src 10.11.12.104
(initramfs)
Clean up:
lxc stop ...
lxc delete ...
sudo ip link del focalbr
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to isc-dhcp in Ubuntu.
https://bugs.launchpad.net/bugs/1937110
Title:
dhcp option 121 & 249
Status in subiquity:
New
Status in isc-dhcp package in Ubuntu:
Fix Released
Status in isc-dhcp source package in Focal:
In Progress
Status in isc-dhcp source package in Jammy:
In Progress
Bug description:
[Impact]
* DHCP classless static routes aren't applied
by dhclient at the initramfs (e.g., ip=dhcp).
* This happens as rfc3442-classless-routes is
not copied to /etc/dhcp/dhclient-exit-hooks.d/
in the initramfs.
* On Jammy, if such DHCP option(s) are present
in the DHCP server response, the DHCP client
ignores the 'routers' option from the server,
thus leaving no routes configured.
* On Focal, the older code still adds 'routers',
which is slightly better, but still does not
add the classless static routes.
[Test Plan]
* Use LXD container/VMs for DHCP server/client,
configure the DHCP server with option 121,
and some sample classless static routes.
(see comments #12/jammy and #13/focal).
[Regression Potential]
* Acquisition of DHCP leases/routes at initramfs
with ip=dhcp.
* The code/script is not new, and is exercised
normally during on rootfs (ie, post-initramfs)
when dhclient is run.
* It's also been in the initramfs in Kinetic
already, since on Aug 2022; giving it tests.
[Original Description]
Hello,
I'm running into issues with subiquity on a cloud provider. The cloud
provider is using an on-link L3 gateway.
His DHCP response looks like this:
OPTION: 53 ( 1) DHCP message type 5 (DHCPACK)
OPTION: 54 ( 4) Server identifier 172.31.1.1
OPTION: 51 ( 4) IP address leasetime 86400 (24h)
OPTION: 1 ( 4) Subnet mask 255.255.255.255
OPTION: 3 ( 4) Routers 172.31.1.1
OPTION: 6 ( 12) DNS server ....
OPTION: 121 ( 14) Classless Static Route 20ac1f0101000000 .......
0000ac1f0101 ......
OPTION: 249 ( 14) MSFT - Classless route 20ac1f0101000000 .......
0000ac1f0101 ......
Im booting the subiquity process with an patched ipxe
(https://github.com/ipxe/ipxe/pull/104) like this:
#!ipxe
kernel .../vmlinuz initrd=initrd root=/dev/ram0 ramdisk_size=1500000 ip=dhcp
url=https://cdimage.ubuntu.com/ubuntu-server/focal/daily-live/current/focal-live-server-amd64.iso
autoinstall ds=nocloud-net;s=.../...-ad-78/ cloud-config-url=/dev/null
initrd .../initrd
boot
initrd/vmlinuz is extracted right out of focal-live-server-amd64.iso
Sadly subiquity is stuck with a broken network (because of missing
dhcp option 121/249 support). It happens when its running the /init
from the kernel right after kernel is booted, i guess even before the
subiquity is started(?).
After further debugging, it looks like the provided kernel 5.4.80 #90
Ubuntu, is using busybox 1.30.1-4ubuntu~6.3 which includes isc-
dhclient-4.4.1 which is lacking the given options.
Would be awesome if this could be fixed.. maybe just a simple busybox
compile option?
To manage notifications about this bug go to:
https://bugs.launchpad.net/subiquity/+bug/1937110/+subscriptions
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