[yocto] Changing over to systemd (no dhcp)

[Andre McCurdy]

On Wed, Jan 18, 2017 at 7:10 AM,  <colin.helliwell at ln-systems.com> wrote:
> We have a configuration for our embedded system which is working via SysV,
> but we’re investigating moving over to systemd.
>
> Not sure if this is ‘wise’ – if anyone has technological arguments
> for/against then I’d be interested – but I wanted to investigate it anyway.
>
> I’ve modified local.conf (right or wrong) with
>
>   DISTRO_FEATURES_append = " systemd"
>   VIRTUAL-RUNTIME_init_manager = "systemd"
>   DISTRO_FEATURES_BACKFILL_CONSIDERED = "sysvinit"
>   VIRTUAL-RUNTIME_initscripts = ""
>   KERNEL_ENABLE_CGROUPS = "1"
>
> I also found a readme
> (https://cgit.freedesktop.org/systemd/systemd/tree/README#n37) about the
> kernel requirements for systemd, and it does at least now boot.
>
> However although eth0 is coming up (‘ifconfig eth0’), there doesn’t seem to
> be any dhcp happening – no IP etc.
>
> Previously (under SysV) I had the busybox dhcp client; now it seems that is
> missing. There’s a symlink /etc/systemd/system/busybox-udhcpc.service to
> /dev/null
>
> I’m using
>
>   Poky Jethro
>   Kernel 4.4.0
>   Busybox 1.23.2 (with ‘CONFIG_FEATURE_SYSTEMD=y’)
>
> I wondered if this is just a simple switch I’m missing somewhere, or is
> there a whole load more modifications I need to dig into and hand-craft?
> (Was hoping for something ‘out of the box’….)

Try:

  VIRTUAL-RUNTIME_initscripts = "systemd-compat-units"

Enabling systemd is somewhat documented by the example in
{meta-poky,openembedded-core/meta}/conf/local.conf.sample.extended,
which is:

#
# Use systemd for system initialization
#
# DISTRO_FEATURES_append = " systemd"
# DISTRO_FEATURES_BACKFILL_CONSIDERED += "sysvinit"
# VIRTUAL-RUNTIME_init_manager = "systemd"
# VIRTUAL-RUNTIME_initscripts = "systemd-compat-units"