[Bug 1579130] Re: need to support systemd.link renaming of devices in container
Scott Moser
smoser at ubuntu.com
Fri May 27 02:19:45 UTC 2016
** Description changed:
We're interested in supporting network configuration of lxc containers
via maas/cloud-init yaml format.
The end goal is to do:
$ lxc init xenial x1
$ ncpath=/var/lib/cloud/seed/nocloud-net/network-config
$ sudo tee /var/lib/lxd/containers/x1/rootfs/$ncpath <<EOF
version: 1
config:
- type: physical
mac_address: "00:16:3e:3b:01:7a"
name: foo2
subnets:
- type: dhcp
control: auto
EOF
$ lxc start x1
$ lxc exec x1 /bin/bash
From inside we expect to have a device named 'foo2' at this point that
has dhcp'd.
We've run into a number of issues with this.
a.) we don't get coldplug events for devices in a container, so writing systemd.link (or 70-persistent-net.rules style udev rules files) wont "just work" to apply the name changes.
- b.) systemd.link does rename devices that have been renamed previously, and all lxd instance devices are renamed (from the kernel returned veth<random> into 'eth0').
+ b.) systemd.link does not rename devices that have been renamed previously, and all lxd instance devices are renamed (from the kernel returned veth<random> into 'eth0').
That is implemented by check of /sys/devices/virtual/net/eth0/name_assign_type . Value of 4 means renamed.
c.) systemd.link will not attempt to rename a device that does not have a driver.
To see that run: udevadm test-builtin net_setup_link /sys/class/net/eth0
http://paste.ubuntu.com/16261974/
To force these systemd.link files to run in spite of 'b' on kvm guests
or bare metal, we have found that unbind and rebind of the device will
clear the state and rename would occur. that can be done as shown in
https://bugs.launchpad.net/ubuntu/+source/cloud-
init/+bug/1577844/comments/3 but since there is no 'driver' we cannot
unbind and rebind veth devices.
Ultimately, we want to allow cloud-init to configure the system once and
then let renaming on reboots not require involvement of cloud-init. And
at the moment the ideal way to affect that would be through systemd.link
files such as /etc/systemd/network/50-cloud-init-foo2.link.
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: udev 229-4ubuntu4
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
Date: Fri May 6 15:42:52 2016
MachineType: LENOVO 33672B7
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-21-generic.efi.signed root=UUID=19ac97d5-6973-4193-9a09-2e6bbfa38262 ro quiet splash vt.handoff=7
SourcePackage: systemd
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/18/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: G8ET96WW (2.56 )
dmi.board.asset.tag: Not Available
dmi.board.name: 33672B7
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrG8ET96WW(2.56):bd12/18/2013:svnLENOVO:pn33672B7:pvrThinkPadX131e:rvnLENOVO:rn33672B7:rvrNotDefined:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 33672B7
dmi.product.version: ThinkPad X131e
dmi.sys.vendor: LENOVO
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https://bugs.launchpad.net/bugs/1579130
Title:
need to support systemd.link renaming of devices in container
Status in cloud-init package in Ubuntu:
Confirmed
Status in systemd package in Ubuntu:
Triaged
Bug description:
We're interested in supporting network configuration of lxc containers
via maas/cloud-init yaml format.
The end goal is to do:
$ lxc init xenial x1
$ ncpath=/var/lib/cloud/seed/nocloud-net/network-config
$ sudo tee /var/lib/lxd/containers/x1/rootfs/$ncpath <<EOF
version: 1
config:
- type: physical
mac_address: "00:16:3e:3b:01:7a"
name: foo2
subnets:
- type: dhcp
control: auto
EOF
$ lxc start x1
$ lxc exec x1 /bin/bash
From inside we expect to have a device named 'foo2' at this point that
has dhcp'd.
We've run into a number of issues with this.
a.) we don't get coldplug events for devices in a container, so writing systemd.link (or 70-persistent-net.rules style udev rules files) wont "just work" to apply the name changes.
b.) systemd.link does not rename devices that have been renamed previously, and all lxd instance devices are renamed (from the kernel returned veth<random> into 'eth0').
That is implemented by check of /sys/devices/virtual/net/eth0/name_assign_type . Value of 4 means renamed.
c.) systemd.link will not attempt to rename a device that does not have a driver.
To see that run: udevadm test-builtin net_setup_link /sys/class/net/eth0
http://paste.ubuntu.com/16261974/
To force these systemd.link files to run in spite of 'b' on kvm guests
or bare metal, we have found that unbind and rebind of the device will
clear the state and rename would occur. that can be done as shown in
https://bugs.launchpad.net/ubuntu/+source/cloud-
init/+bug/1577844/comments/3 but since there is no 'driver' we cannot
unbind and rebind veth devices.
Ultimately, we want to allow cloud-init to configure the system once
and then let renaming on reboots not require involvement of cloud-
init. And at the moment the ideal way to affect that would be through
systemd.link files such as /etc/systemd/network/50-cloud-init-
foo2.link.
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: udev 229-4ubuntu4
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
Date: Fri May 6 15:42:52 2016
MachineType: LENOVO 33672B7
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-21-generic.efi.signed root=UUID=19ac97d5-6973-4193-9a09-2e6bbfa38262 ro quiet splash vt.handoff=7
SourcePackage: systemd
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/18/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: G8ET96WW (2.56 )
dmi.board.asset.tag: Not Available
dmi.board.name: 33672B7
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrG8ET96WW(2.56):bd12/18/2013:svnLENOVO:pn33672B7:pvrThinkPadX131e:rvnLENOVO:rn33672B7:rvrNotDefined:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 33672B7
dmi.product.version: ThinkPad X131e
dmi.sys.vendor: LENOVO
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