原始参考：https://github.com/ros/meta-ros/blob/kirkstone-next/meta-ros-common/recipes-core/images/ros-image-world.bb 注意它的inherit:

inherit ros_distro_${ROS_DISTRO}
inherit ${ROS_DISTRO_TYPE}_image

但我们在工作目录的bblayers.conf中有设置：

ROS_DISTRO = "humble"
ROS_DISTRO_TYPE = "ros2"

所以，它会先inherit ros_distro_humble, 这个对应是https://github.com/ros/meta-ros/blob/kirkstone-next/meta-ros2-humble/classes/ros_distro_humble.bbclass ，内容如下：

ROS_DISTRO = "humble"
inherit ${ROS_DISTRO_TYPE}_distro

上面会继承https://github.com/ros/meta-ros/blob/kirkstone-next/meta-ros2/classes/ros2_distro.bbclass

看来没啥毛病，只是我们编译的包没带ros2可执行的文件，突然看到： https://github.com/ros/meta-ros/blob/kirkstone/meta-ros2/recipes-core/packagegroups/packagegroup-ros2-demos.bb

这里面应该会编译出ros2节点所需的例程，在image中加上这个

IMAGE_INSTALL:append = " \
    packagegroup-ros-world \
"