set nice level of work intensive tasks

defaults/main.yml

@@ -20,3 +20,5 @@ live_build_directory: /opt/live
 live_build_desktop: true
 
 live_build_iso_publisher: custom
+
+live_build_nice_level: 14

tasks/build.yaml

@@ -1,25 +1,33 @@
 ---
 
 - name: lb bootstrap (first build stage)
-  command: lb bootstrap
+  command:
+    nice -n {{ live_build_nice_level }}
+    lb bootstrap
   args:
     chdir: "{{ live_build_directory }}"
   register: _lb_bootstrap
 
 - name: lb chroot (second build stage)
-  command: lb chroot
+  command:
+    nice -n {{ live_build_nice_level }}
+    lb chroot
   args:
     chdir: "{{ live_build_directory }}"
   register: _lb_chroot
 
 - name: lb installer (third build stage)
-  command: lb installer
+  command:
+    nice -n {{ live_build_nice_level }}
+    lb installer
   args:
     chdir: "{{ live_build_directory }}"
   register: _lb_installer
 
 - name: lb binary (fourth build stage)
-  command: lb binary
+  command:
+    nice -n {{ live_build_nice_level }}
+    lb binary
   args:
     chdir: "{{ live_build_directory }}"
   register: _lb_binary