title: How to modify the alert manager's threshold value
body: <p>I use a node exporter program to monitor the CPU's threshold and receive notifications.
  The example below is a rule file that sets conditions when it is more than 80%.</p>
  <pre><code>alert: HostHighCpuLoad
  expr: 100 - (avg by(instance) (rate(node_cpu_seconds_total{mode=&quot;idle&quot;}[2m])) * 100) &gt; 80
  for: 0m
  labels:
    severity: warning
  annotations:
    summary: Host high CPU load (instance {{ $labels.instance }})
    description: &quot;CPU load is &gt; 80%\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}&quot; 
  </code></pre>
  <p>I need to receive a threshold from the web UI and change the threshold set in the rule file to 70%.
  Can I convert the threshold into a variable?</p>
  <pre><code>expr: 100 - (avg by(instance) (rate(node_cpu_seconds_total{mode=&quot;idle&quot;}[2m])) * 100) &gt; {THRESHOLD_VALUE} 
  </code></pre>
  <p>Or I wonder if I should make a script that modifies the 80% value to 70%.
  Please give me advice.</p>