docs updated

src/kubernetes/tips.rst

@@ -1421,3 +1421,54 @@ you don't need a service.
 Think of the service as a kind of specialized load-balancer in front of an (HTTP?)
 API your pods expose. Since you don't have that API, you don't need it.
 
+
+Monitoring
+----------
+
+.. code-block:: bash
+
+    #!/bin/bash
+    #
+    # Monitor overall Kubernetes cluster utilization and capacity.
+    #
+    # Original source:
+    # https://github.com/kubernetes/kubernetes/issues/17512#issuecomment-367212930
+    #
+    # Tested with:
+    #   - AWS EKS v1.11.5
+    #
+    # Does not require any other dependencies to be installed in the cluster.
+
+    set -e
+
+    KUBECTL="kubectl"
+    NODES=$($KUBECTL get nodes --no-headers -o custom-columns=NAME:.metadata.name)
+
+    function usage() {
+      local node_count=0
+      local total_percent_cpu=0
+      local total_percent_mem=0
+      local readonly nodes=$@
+
+      for n in $nodes; do
+        local requests=$($KUBECTL describe node $n | grep -A3 -E "\\s\sRequests" | tail -n2)
+        local percent_cpu=$(echo $requests | awk -F "[()%]" '{print $2}')
+        local percent_mem=$(echo $requests | awk -F "[()%]" '{print $8}')
+        echo "$n: ${percent_cpu}% CPU, ${percent_mem}% memory"
+
+        node_count=$((node_count + 1))
+        total_percent_cpu=$((total_percent_cpu + percent_cpu))
+        total_percent_mem=$((total_percent_mem + percent_mem))
+      done
+
+      local readonly avg_percent_cpu=$((total_percent_cpu / node_count))
+      local readonly avg_percent_mem=$((total_percent_mem / node_count))
+
+      echo "Average usage: ${avg_percent_cpu}% CPU, ${avg_percent_mem}% memory."
+    }
+
+    usage $NODES
+
+https://github.com/derailed/k9s
+
+https://github.com/robscott/kube-capacity