tips-and-tricks.md

 # Tips and tricks
 
-## Check availability and status of Kubernetes resources
-In a terminal connected to the master node:
+## Kubernetes troubleshooting
+
+(For much more, see [Kubernetes](https://kubernetes.io/).)
+
+Execute commands listed below in a terminal connected to the master node.
+
+### Get an overview
 ```
 kubectl get nodes
 kubectl get deployments
 kubectl get pods
 ```
 
-## Open a terminal to a node
-From a terminal connected to the master node:
+### Obtain node information
 ```
-kubectl get nodes
-# select a <NAME> from the left column of the output of above
+# select a <NAME> from the left column of the output of kubectl get nodes
+kubectl describe node <NAME>
+```
+
+### Open a terminal to a node
+```
+# select a <NAME> from the left column of the output of kubectl get nodes
 ssh <NAME>
 ```
 
-## Open a terminal to a pod
-From a terminal connected to the master node:
+### Open a terminal to a pod
 ```
-kubectl get pods
-# select a <NAME> from the left column of the output of above
+# select a <NAME> from the left column of the output of kubectl get pods
 kubectl exec -i -t <NAME> bash
 ```
 
+## Kubernetes memory requirements dimensioning
+In order to obtain good values for the `spec.template.spec.containers[].resources` section of a deployment spec,
+as in this example:
+```
+          requests:
+            memory: "60Mi"
+            cpu: "10m"
+          limits:
+            memory: "80Mi"
+            cpu: "60m"
+```
+proceed as follows:
+* Set the values high.
+* Configure the experiment to have only 1 replica of this deployment.
+* Make an *espec* that provides enough nodes so that the pod for this deployment runs on a node where no other pods run.
+* Launch the experiment.
+* Open a terminal to the pod under investigation.
+* Monitor actual resource consumption using the *top* command.
+* Adapt values and set number of replicas back to the desired value.
+
 ## Grafana dashboard definition in the Kubernetes configuration
 Proceed as follows:
 * Design the Dashboard interactively in the Grafana webinterface.
@@ -47,3 +74,4 @@ as in **launch-experiment.sh** in the
   --from-file=dashboard1.json=dashboard1.json \
   ```
 
+