This lab guides the student through basic Prometheus Queries (PromQL) and demonstrates how the Kubernetes architecture may be interrogated. The lab also introduces a simple means of stressing a cluster and demonstrates how those techniques affect the metrics being stored in the time series database.
Learning Objectives
Successfully complete this lab by achieving the following learning objectives:
- Check that your lab environment is ready.
Log in to the master node:
ssh cloud_user@[Public IP here]List the home directory contents:
ls -lVerify that
stress-test.yamlis present.- Access Prometheus from your browser.
Access Prometheus from your browser:
http://[Master Node public ip address]:9090You may also access the sAdvisor dashboard at the following address:
http://[Worker Node Public IP Address]:8080- Use the provided PromQL queries to interrogate your cluster.
The following are the suggested PromQL queries you may perform.
To measure CPU utilization:
node_cpu_seconds_totalirate(node_cpu_seconds_total{job="node"}[5m])avg(irate(node_cpu_seconds_total{job="node"}[5m])) by (instance)avg(irate(node_cpu_seconds_total{job="node",mode="idle"}[5m])) by (instance) * 100100 - avg(irate(node_cpu_seconds_total{job="node",mode="idle"}[5m])) by (instance) * 100To measure memory, use:
(node_memory_MemTotal_bytes - (node_memory_MemFree_bytes + node_memory_Cached_bytes + node_memory_Buffers_bytes)) / node_memory_MemTotal_bytes * 100- Deploy the stress test and vary its replicas to examine changes.
In the terminal emulator session that is established to the Master Node:
Deploy the Stress-Test Deployment:
kubectl create -f stress-test.yamlInterrogate the number of replicas deployed:
kubectl get deploymentsInterrogate the pods running:
kubectl get pods- Refresh your Prometheus graphs and scale the deployment up and down to vary metrics.
Use refresh on your browser to see the time series metrics change over time.
Use the following command to increase and decrease the number of replicas running in the stress-test deployment.
kubectl scale deployment.v1.apps/stress-test --replicas=[from 1 to 50 here]
