From aca45c58207788bb9179f1ce9e128f10ea1967e9 Mon Sep 17 00:00:00 2001
From: "James O. D. Hunt" <james.o.hunt@intel.com>
Date: Fri, 18 May 2018 11:05:12 +0100
Subject: [PATCH] image: Require systemd

Building an image requires systemd to be installed in the rootfs as the
init daemon, so assert that systemd is available.

Updated tests so that alpine is only tested as an initrd (it cannot be
an image as it doesn't use systemd).

Added warning note about alpine to the docs.

Fixes #98.

Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>
---
 image-builder/README.md        |  3 +++
 image-builder/image_builder.sh |  9 +++++++++
 rootfs-builder/README.md       |  3 +++
 tests/image_creation.bats      | 18 +++++++++++-------
 4 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/image-builder/README.md b/image-builder/README.md
index 21bb9c24b5..b4475fced9 100644
--- a/image-builder/README.md
+++ b/image-builder/README.md
@@ -16,6 +16,9 @@ $ sudo ./image_builder.sh path/to/rootfs
 
 Where `path/to/rootfs` is the directory populated by `rootfs.sh`.
 
+> **Note**: If you are building an image from an Alpine rootfs, see
+> the important note [here](rootfs-builder/README.md#rootfs-requirements).
+
 ## Further information
 
 For more information about usage (including how to adjust the size of the
diff --git a/image-builder/image_builder.sh b/image-builder/image_builder.sh
index 492633f470..0b78de3575 100755
--- a/image-builder/image_builder.sh
+++ b/image-builder/image_builder.sh
@@ -117,6 +117,15 @@ init_path="/sbin/init"
 init="${ROOTFS}${init_path}"
 [ -x "${init}" ] || [ -L ${init} ] || die "${init_path} is not installed in ${ROOTFS}"
 OK "init is installed"
+
+if [ "${AGENT_INIT}" == "no" ]
+then
+	systemd_path="/lib/systemd/systemd"
+	systemd="${ROOTFS}${systemd_path}"
+	[ -x "${systemd}" ] || [ -L ${systemd} ] || die "${systemd_path} is not installed in ${ROOTFS}"
+	OK "init is systemd"
+fi
+
 [ "${AGENT_INIT}" == "yes" ] || [ -x "${ROOTFS}/usr/bin/${AGENT_BIN}" ] || \
 	die "/usr/bin/${AGENT_BIN} is not installed in ${ROOTFS}
 	use AGENT_BIN env variable to change the expected agent binary name"
diff --git a/rootfs-builder/README.md b/rootfs-builder/README.md
index 36c3dc4a92..56604fbc15 100644
--- a/rootfs-builder/README.md
+++ b/rootfs-builder/README.md
@@ -41,6 +41,9 @@ The rootfs must provide at least the following components:
 
 When the `AGENT_INIT` environment variable is set to `yes`, use Kata agent as `/sbin/init`.
 
+> **Note**: `AGENT_INIT=yes` **must** be used for the Alpine distribution
+> since it does not use `systemd` as its init daemon.
+
 ## Creating a rootfs
 
 To build a rootfs for your chosen distribution, run:
diff --git a/tests/image_creation.bats b/tests/image_creation.bats
index 724f098b94..7c552c7c82 100644
--- a/tests/image_creation.bats
+++ b/tests/image_creation.bats
@@ -48,22 +48,26 @@ function build_initrd()
 function build_rootfs_image_initrd()
 {
 	distro="$1"
+	image="$2"
+	initrd="$3"
+
 	[ -n "$distro" ]
 	build_rootfs $distro
-	build_image
-	build_initrd
+
+	[ "$image" = "yes" ] && build_image
+	[ "$initrd" = "yes" ] && build_initrd
 }
 
 @test "Can create fedora image" {
-	build_rootfs_image_initrd fedora
+	build_rootfs_image_initrd fedora yes yes
 }
 
 @test "Can create clearlinux image" {
-	build_rootfs_image_initrd clearlinux
+	build_rootfs_image_initrd clearlinux yes yes
 }
 
 @test "Can create centos image" {
-	build_rootfs_image_initrd centos
+	build_rootfs_image_initrd centos yes yes
 }
 
 @test "Can create euleros image" {
@@ -71,9 +75,9 @@ function build_rootfs_image_initrd()
 	then
 		skip "travis timeout, see: https://github.com/kata-containers/osbuilder/issues/46"
 	fi
-	build_rootfs_image_initrd euleros
+	build_rootfs_image_initrd euleros yes yes
 }
 
 @test "Can create alpine image" {
-	build_rootfs_image_initrd alpine
+	build_rootfs_image_initrd alpine no yes
 }