containers: introduce sample/reference container-base image type

container-base is a sample/reference image type that uses the
newly integrated image-oci image type to directly create OCI
compatible images from a build.

This image type can be inherited and extended to implement more
complex container types, with modified image configurations.

It is inspired by / based off the samples in the presentation
done by Scott Murray (Building Container Images with
OpenEmbedded and the Yocto Project) at ELCe 2018.

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

recipes-extended/images/container-base.bb

@@ -0,0 +1,28 @@
+#
+# Based on examples from Scott Murray (Building Container Images with
+# OpenEmbedded and the Yocto Project) ELCe 2018
+#
+SUMMARY = "Basic container image"
+LICENSE = "MIT"
+LIC_FILES_CHKSUM = "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
+
+IMAGE_FSTYPES = "container oci"
+inherit image
+inherit image-oci
+
+IMAGE_FEATURES = ""
+IMAGE_LINGUAS = ""
+NO_RECOMMENDATIONS = "1"
+
+IMAGE_INSTALL = " \
+       base-files \
+       base-passwd \
+       netbase \
+"
+
+# Workaround /var/volatile for now
+ROOTFS_POSTPROCESS_COMMAND += "rootfs_fixup_var_volatile ; "
+rootfs_fixup_var_volatile () {
+    install -m 1777 -d ${IMAGE_ROOTFS}/${localstatedir}/volatile/tmp
+    install -m 755 -d ${IMAGE_ROOTFS}/${localstatedir}/volatile/log
+}