Make kernel state more flexible.

Signed-off-by: Maximilian Wilhelm <max@rfc2324.org>

kernel/init.sls

@@ -2,17 +2,22 @@
 # Linux Kernel
 #
 
-linux-4.7:
+{% set node_config = salt['pillar.get']('nodes:' ~ grains['id'], {}) %}
+{% set version_fallback = "4.8.0-0.bpo.2-amd64" %}
+{% set version_global = salt['pillar.get']('ffho:kernel_version', version_fallback) %}
+{% set version = node_config.get('kernel_version', version_global) %}
+
+linux-kernel:
   pkg.installed:
-    - name: linux-image-4.7.0-0.bpo.1-amd64
+    - name: linux-image-{{ version }}
     - fromrepo: jessie-backports
 
 {#
  # Install kernel headers if we might need to compile a batman_adv module on this node.
  #}
-{% if 'batman' in salt['pillar.get']('nodes:' ~ grains['id'] ~ ':roles', []) %}
-linux-4.7-headers:
+{% if 'batman' in node_config.get('roles', []) %}
+linux-headers:
   pkg.installed:
-    - name: linux-headers-4.7.0-0.bpo.1-amd64
+    - name: linux-headers-{{ version }}
     - fromrepo: jessie-backports
 {% endif %}