<p>I am trying to understand default prometheus rules for kubernetes. And then I came across with this expression:</p>
<pre><code>      sum(namespace_cpu:kube_pod_container_resource_requests:sum{})
        /
      sum(kube_node_status_allocatable{resource=&quot;cpu&quot;})
        &gt;
      ((count(kube_node_status_allocatable{resource=&quot;cpu&quot;}) &gt; 1) - 1) / count(kube_node_status_allocatable{resource=&quot;cpu&quot;})
</code></pre>
<p>Specifically, i am curious at <code>namespace_cpu:kube_pod_container_resource_requests:sum{}</code>. namespace_cpu does not appear to be an operation or reserved word in promql.</p>
<p>I can't seem to find it either in Prometheus documentation. <a href="https://prometheus.io/docs/prometheus/latest/querying/basics/" rel="nofollow noreferrer">https://prometheus.io/docs/prometheus/latest/querying/basics/</a></p>
<p>Any hints?</p>

<p>Nothing, it's not an operator <code>:</code> is just a legal character in metric names. Some standard rulesets use it for grouping rollup rules together but it's just a naming scheme at most.</p>
