Hi,

Here's an example of mongodb_%.bbappend file:

-----------------------------------------------------------------------------
FILESEXTRAPATHS_prepend := "${THISDIR}/files:"

SRC_URI += "file://mongod.conf file://mongod.service"

inherit systemd

do_install_append() {
# config
install -d ${D}${sysconfdir}
install -m 0644 ${WORKDIR}/mongod.conf ${D}${sysconfdir}/

# systemd
install -d ${D}${systemd_unitdir}/system/
install -m 0644 ${WORKDIR}/mongod.service ${D}${systemd_unitdir}/system/
}

SYSTEMD_SERVICE_${PN} = "mongod.service"
-----------------------------------------------------------------------------

And create a folder meta-x/recipes-dbs/mongodb/files with
mongod.service and mongod.conf in it.

Best Regards,
Vincent