Split out SystemLoad alerts for Nova Compute nodes.

Fixes PROD-34626

Change-Id: If8198f27b013b680bf02743cba9fd91f2e477734
diff --git a/linux/meta/prometheus.yml b/linux/meta/prometheus.yml
index 865f744..5a0941c 100644
--- a/linux/meta/prometheus.yml
+++ b/linux/meta/prometheus.yml
@@ -36,11 +36,14 @@
       annotations:
         summary: "{%- endraw %}{{ cpu_usage_threshold }}{%- raw %}% CPU usage"
         description: "The average CPU usage on the {{ $labels.host }} node is {{ $value }}% for 2 minutes."
-    SystemLoadTooHighWarning:
       {%- endraw %}
+    {% if not ([
+        salt['pillar.get']('nova:compute:enabled', False)
+    ]|select('equalto', True)|list) %} {# glorified `not any(<iterable>)` condition #}
+    SystemLoadTooHighWarning:
       {%- set load_threshold = monitoring.system_load_threshold.warn|float %}
       if: >-
-        system_load15 / system_n_cpus > {{ load_threshold }}
+        system_load15{host!~".*cmp[0-9]+"} / system_n_cpus > {{ load_threshold }}
       {%- raw %}
       for: 5m
       labels:
@@ -49,11 +52,11 @@
       annotations:
         summary: "System load is {%- endraw %}{{ load_threshold }}{%- raw %}"
         description: "The system load per CPU on the {{ $labels.host }} node is {{ $value }} for 5 minutes."
-    SystemLoadTooHighCritical:
       {%- endraw %}
+    SystemLoadTooHighCritical:
       {%- set load_threshold = monitoring.system_load_threshold.crit|float %}
       if: >-
-        system_load15 / system_n_cpus > {{ load_threshold }}
+        system_load15{host!~".*cmp[0-9]+"} / system_n_cpus > {{ load_threshold }}
       {%- raw %}
       for: 5m
       labels:
@@ -62,8 +65,9 @@
       annotations:
         summary: "System load is {%- endraw %}{{ load_threshold }}{%- raw %}"
         description: "The system load per CPU on the {{ $labels.host }} node is {{ $value }} for 5 minutes."
-    SystemDiskFullWarning:
       {%- endraw %}
+    {% endif %}
+    SystemDiskFullWarning:
       {%- set disk_threshold = monitoring.disk_usage_percentage.warn|float %}
       if: >-
         disk_used_percent >= {{ disk_threshold }}
diff --git a/tests/test-requirements.txt b/tests/test-requirements.txt
index 0480052..bc7dc7f 100644
--- a/tests/test-requirements.txt
+++ b/tests/test-requirements.txt
@@ -1,3 +1,4 @@
 jsonschema
 reno
-setuptools<45.0.0
\ No newline at end of file
+setuptools<45.0.0
+msgpack<1.0.0