introduce Makefile to simplify building templates

updated ubuntu/centos templates to fixed output names,
moved manifest.json to builder's subfolder,
updated README.md to reflect the changes

1 files changed, 29 insertions, 12 deletions

diff --git a/README.md b/README.md
index aefd6d9..295e3b0 100644
--- a/README.md
+++ b/README.md
@@ -15,24 +15,24 @@ The root password is expected to be in the ROOTPW environment variable.
 The installation procedure will fail without it!
 
 Basic usage:
+```shell
 	ROOTPW=<password> packer build -var-file=base.json <template>
-
-For the rest of the examples, the root password is expected to be exported.
+```
+For the rest of the examples, ROOTPW is assumed to be set in the environment.
 
 ## Usage: Creating base images
 
-Example: build Ubuntu 16.04.2 LTS template using qemu builder
+Example - Build Ubuntu 16.04.2 LTS template using qemu builder
+```shell
 	packer build -var-file=base.json -only=qemu ubuntu-16.04-amd64.json
-
+```
 Debug:
+```shell
 	PACKER_LOG=1 PACKER_LOG_FILE=/var/log/packer.log \
 		packer build -debug -only=qemu -var-file=base.json ubuntu-16.04-amd64.json
-
+```
 A successful build process would produce a disk image under:
-	output-<distro>-<builder>-<timestamp>/packer-<distro>
-
-Example:
-  output-ubuntu-qemu-1490876841/packer-ubuntu-amd64
+	<builder>/<template>, e.g. qemu/centos-7.3-x86_64
 
 Additionally, the manifest post-processor creates a manifest.json file in
 the working directory containing various information about the generated
@@ -54,9 +54,12 @@ Refer to those repos for more information. The simpliest way to initialize
 the submodule is by cloning this repository with '--recursive'.
 
 Build initramfs inside a previously created image:
+```shell
 	packer build -var-file=base.json \
 		-var='image_path='"$(jq -r '.builds[0].files[0].name' < manifest.json)"'' \
 		ansible-roles/run-playbook-only.json
+```
+(This expects 'manifest.json' to contain only one packer artifact.)
 
 The path to the existing image is extracted using the jq tool and given as
 'image_path' to the packer provisioning template run-playbook-only.json.
@@ -64,15 +67,27 @@ A successful build would provide the stage3 initramfs and the VM's kernel
 in the ansible-roles/boot_files/ directory. Refer to systemd-init for more
 information on how to setup a boot environment.
 
-The packer artifact is created as output-<timestamp>. This provisioned image
+The packer artifact is created in 'output-<timestamp>'. This artifact
 contains all the development packages needed to build the initramfs, which
-can be discarded.
+can be discarded. Instead, the base image can be used as the main boot image.
+
+## Makefile
+
+A simple Makefile to build packer templates is provided for convenience.
+See a list of targets with `make list`.
+
+Example - Build CentOS 7.3 with qemu:
+```shell
+	make qemu/centos-7.3-x86_64
+```
 
 ## Notes
 
 Variables set in base.json can be overriden using packer's '-var' options, e.g.:
+```shell
 	packer build -var-file=base.json -var='headless=true' <template>
-(Make sure you first include base.json before overriding a variable!)
+```
+Make sure you first include base.json before overriding a variable!
 
 The partitioning of the virtual disk is done via kickstart/preseed files. Currently,
 a simple partition scheme is used: separate boot partition, rest a the main system
@@ -81,7 +96,9 @@ supported, tested were currently xfs and btrfs. If you change the filesystem to
 you need to adapt your boot configuration file (SLX_MOUNT_ROOT_OPTIONS).
 
 While the qemu builder produces a qcow2 image, it can be further compressed using:
+```shell
 	virt-sparsify --compress <qcow2_file> <output_qcow2_file>
+```
 
 ## TL;DR
 0) git clone --recursive git://git.openslx.org/openslx-ng/packer-templates