Kubernetes Command-Line Basics with kubectl http://bit.ly/k8s-kubectl

kubernetes-cli-basics-with-kubectl.html

<section>
<section id="kubernetes-cli-basics-with-kubectl">
  <a href="http://kubernetes.io/"><img src="https://pbs.twimg.com/profile_images/511909265720614913/21_d3cvM.png" alt="kubernetes" style='width:33%;'></a>
  <h2>Kubernetes Command-Line Basics</h2>
  <h3>with <a href="https://kubernetes.io/docs/user-guide/kubectl/"><code>kubectl</code></a></h3>
  <br/>
  <h4 class='fragment grow'><a href="http://bit.ly/k8s-kubectl"><code>bit.ly/k8s-kubectl</code></a></h4> 
</section>
  <section data-background='black' id='presented-by-ryanj'>
    <p>presented by <a href="http://twitter.com/ryanj/">@ryanj</a>, Developer Advocate at <a href='http://redhat.com' style='color:red;'>Red Hat</a></p>
    <p><a href="http://twitter.com/ryanj/"><img alt="ryanj" src="http://ryanjarvinen.com/images/ryanj-mestrefungo-com.gif" style="width:50%" /></p>     
  </section>
  <!--
  <section id='brought-to-you-by' data-markdown>
    brought to you by
    
    [![CoreOS Logo](http://i.imgur.com/DRm4KEq.png "")](https://coreos.com)
    
    *Continuously ready to face the challenges of a modern world*
    
    Join us in our goal to *Secure the Internet* by chosing solutions that are designed with Continuous Security in mind
    
  </section>
  -->
</section>
  

<section>
  <section id='overview'>
  <h2>Overview</h2>
  <ol>
    <li class='fragment'><a href="#/kubernetes-basics">Kubernetes Basics</a>
      <ul>
        <li><a href="#/why-k8s">Why Kubernetes?</a></li>
        <li><a href="#/terminology">Learn five K8s Primitives</a></li>
      </ul>
    </li>
  </ol>
  </section>
  <!--
   <section id='survey'>
  <h3>Intro Survey / Who are you?</h3>
<ol>
<li class='fragment'>doing anything with containers today?</li>
<li class='fragment'>have you tried Container Linux?</li>
<li class='fragment'>do you have any experience using Kubernetes?</li>
<li class='fragment'>do you consider yourself to be proficient with the <code>kubectl</code> cli tool?</li>
<li class='fragment'>can you name five basic primitives or resource types?</li>
<li class='fragment'>can you name five pieces of k8s architecture?</li>
<li class='fragment'>can you confidently define the term "K8s operator"?</li>
<li class='fragment'>do you have any hands-on experience using operators?</li>
</ol>
  </section>
  -->
</section>

<section>
<section id='kubernetes-basics' data-markdown>
  # Kubernetes Basics
</section>
<section id='why-k8s'>
  <h3>Why Kubernetes?</h3>
  <p><img src="https://pbs.twimg.com/profile_images/511909265720614913/21_d3cvM.png" alt="kubernetes" style='width:30%;'></p>
</section>
<section id='k8s-is'>    
  <h3>Kubernetes is...</h3>
<ol>
  <li class='fragment'>An open source platform for running container-based distributed solutions, featuring a modular, HA systems architecture</li>
  <li class='fragment'>The best way to actively manage distributed solutions at scale, based on years of industry expertise (Google-scale experience)</li>
  <li class='fragment'>An extensible distributed-solutions modeling language with a huge community following</li>
  <li class='fragment'>A multi-vendor effort to eliminate cloud lock-in through the adoption of "cloud native" solutions (capable of runnning on any infrastructure)</li>
</ol>
</section>
<section id='an-api' data-markdown>
Kubernetes provides&hellip;
## An API
    
API object primitives include the following attributes:
    
```
kind
apiVersion
metadata
spec
status
```

*mostly true
    
</section>
<section data-transition="linear" id='terminology' data-markdown>
  ### Basic K8s Terminology
  
    1. [node](#/node)
    2. [pod](#/po)
    3. [service](#/svc)
    4. [deployment](#/deploy)
    5. [replicaSet](#/rs) 
</section>
</section>
<section>
  <section data-transition="linear" id='node' data-markdown>
    ### Node
    
    A node is a host machine (physical or virtual) where containerized processes run. 
    
    Node activity is managed via one or more Master instances.
    
  </section>
  <section>
    <p>Try using <code>kubectl</code> to list resources by type:</p>
    <pre><code contenteditable>kubectl get nodes</code></pre>
    <p>Request the same info, but output the results as structured yaml:</p>
    <pre><code contenteditable>kubectl get nodes -o yaml</code></pre>
    <p>Fetch an individual resource by <code>type/id</code>, output as <code>json</code>:</p>  
    <pre><code contenteditable>kubectl get node/minikube -o json</code></pre>
    <p>View human-readable API output:</p>
    <pre><code contenteditable>kubectl describe node/minikube</code></pre>
  </section>
  <section data-markdown>  
  ### Observations:

  * Designed to exist on multiple machines (distributed system)
    * high availability of nodes
    * platform scale out
  * The API ambidextriously supports both json and yaml
    
  </section>
</section>
<section>
  <section data-transition="linear" id='po' data-markdown>
    ### Pod
    A group of one or more co-located containers. Pods represent your minimum increment of scale.
  
    > "Pods Scale together, and they Fail together" @theSteve0
  </section>
  <section>
    <p>List resources by type:</p>
    <pre><code contenteditable>kubectl get pods</code></pre>   
    <p>Create a new resource based on a json object specification:</p>
    <pre><code contenteditable>curl https://raw.githubusercontent.com/ryanj/metrics-k8s/master/pod.json</code></pre>
    <pre><code contenteditable>kubectl create -f https://raw.githubusercontent.com/ryanj/metrics-k8s/master/pod.json</code></pre>
    <p>List resources by type:</p>
    <pre><code contenteditable>kubectl get pods</code></pre>    
    <p>Fetch a resource by type and id, output the results as <code>yaml</code>:</p>
    <pre><code contenteditable>kubectl get pod metrics-k8s -o yaml</code></pre>
    <p>Notice any changes?</p>
  </section>
  <section data-markdown>  
  ### Observations:

  * pods are scheduled to be run on nodes
  * asyncronous fulfilment of requests
  * declarative specifications
  * automatic health checks, lifecycle management for containers (processes)
  
  </section>

  <!--
  <section data-markdown>  
  </section>
  -->
</section>
<section>
  <section data-transition="linear" id='svc' data-markdown>
    ### Service
    Services (svc) establish a single endpoint for a collection of replicated pods, distributing inbound traffic based on label selectors
    
    In our K8s modeling language they represent a load balancer. Their implementation often varies per cloud provider
  </section>
  <section id='services'>
    <h3>Contacting your App</h3>
    <p>Expose the pod by creating a new <code>service</code> (or "loadbalancer"):</p>
    <pre><code contenteditable>kubectl expose pod/metrics-k8s --port 2015 --type=NodePort</code></pre>
    <p>Contact your newly-exposed pod using the associated service id:</p>
    <pre><code contenteditable>minikube service metrics-k8s</code></pre>
    <p>Schedule a pod to be deleted:</p>
    <pre><code contenteditable>kubectl delete pod metrics-k8s</code></pre>
    <p>Contact the related service. What happens?:</p>
    <pre><code contenteditable>minikube service metrics-k8s</code></pre>
    <p>Delete the service:</p>
    <pre><code contenteditable>kubectl delete service metrics-k8s</code></pre>
  </section>
  <section data-markdown>  
  ### Observations:

  * *"service"* basically means *"loadbalancer"*
  * Pods and Services exist independently, have disjoint lifecycles 
    
  </section>
</section>
<section>
  <section data-transition="linear" id='deploy' data-markdown>
    ### Deployment
    A `deployment` helps you specify container runtime requirements (in terms of pods)
  </section>
  <section>
    <p>Create a specification for your <code>deployment</code>:</p>
    <pre><code contenteditable>kubectl run metrics-k8s --image=quay.io/ryanj/metrics-k8s \
--expose --port=2015 --service-overrides='{ "spec": { "type": "NodePort" } }' \
--dry-run -o yaml > deployment.yaml</code></pre>
    <p>View the generated deployment spec file:</p>
    <pre><code contenteditable>cat deployment.yaml</code></pre>
  </section>
  <section>
    <p>Create a new resource based on your yaml specification:</p>
    <pre><code contenteditable>kubectl create -f deployment.yaml</code></pre>
    <p>List resources by type:</p>
    <pre><code contenteditable>kubectl get po,svc</code></pre>
    <p>Connect to your new deployment via the associated service id:</p>
    <pre><code contenteditable>minikube service metrics-k8s</code></pre>
  </section>
  <section id='replication'>
    <h2>Replication</h2>
    <p>Scale up the <code>metrics-k8s</code> deployment to 3 replicas:</p>
    <pre><code contenteditable>kubectl scale deploy/metrics-k8s --replicas=3</code></pre>
    <p>List pods:</p>
    <pre><code contenteditable>kubectl get po</code></pre>
  </section>
  <section>
    <p>Edit <code>deploy/metrics-k8s</code>, setting <code>spec.replicas</code> to <code>5</code>:</p>
    <pre><code contenteditable>kubectl edit deploy/metrics-k8s -o json</code></pre>
    <p>Save and quit. What happens?</p>
    <pre><code contenteditable>kubectl get pods</code></pre>
  </section>
  <section id='autorecovery'>
    <h2>AutoRecovery</h2>
    <p>Watch for changes to <code>pod</code> resources:</p>
    <pre><code contenteditable>kubectl get pods --watch</code></pre>
    <p>In another terminal, delete several pods by id:</p>
    <pre><code contenteditable>kubectl delete pod $(kubectl get pods | grep ^metrics-k8s | cut -f1 -s -d' ' | head -n 3 | tr '\n' ' ')</code></pre>
    <p>What happend? How many pods remain?</p>
    <pre><code contenteditable>kubectl get pods</code></pre>
  </section>
  <section data-markdown>  
  ### Observations:

  * Use the `--dry-run` flag to generate new resource specifications
  * A deployment spec contains a pod spec
  
  </section>
</section>
<section>
  <section data-transition="linear" id='rs' data-markdown>
    ### ReplicaSet
    A `replicaset` provides replication and lifecycle management for a specific image release
  </section>
  <section>
    <p>Watch deployments (leave this running until the 'cleanup' section):</p>
    <pre><code contenteditable>kubectl get deploy --watch</code></pre>
    <p>View the current state of your deployment:</p>
    <pre><code contenteditable>minikube service metrics-k8s</code></pre>
  </section>
  <section>
    <h3>Rollouts</h3>
    <p>Update your deployment's image spec to rollout a new release:</p>
    <pre><code contenteditable>kubectl set image deploy/metrics-k8s metrics-k8s=quay.io/ryanj/metrics-k8s:v1</code></pre>
    <p>Reload your browser to view the state of your deployment</p>
    <pre><code contenteditable>kubectl get rs,deploy</code></pre> 
  </section>
  <section>
    <h3>Rollbacks</h3>
    <p>View the list of previous rollouts:</p>
    <pre><code contenteditable>kubectl rollout history deploy/metrics-k8s</code></pre>
    <p>Rollback to the previous state:</p>
    <pre><code contenteditable>kubectl rollout undo deployment metrics-k8s</code></pre>
    <p>Reload your browser to view the state of your deployment</p>
  </section>
  <section>
    <h3>Cleanup</h3>
    <p>Cleanup old resources if you don't plan to use them:</p>
    <pre><code contenteditable>kubectl delete service,deployment metrics-k8s</code></pre>
    <p>Close any remaining <code>--watch</code> listeners</p>
  </section>
  <section data-markdown>  
  ### Observations:

  * The API allows for watch operations (in addition to get, set, list)
  * ReplicaSets provide lifecycle management for pod resources
  * Deployments create ReplicaSets to manage pod replication per rollout (per change in podspec: image:tag, environment vars)
  
  </section>
</section>
<section>
  <!--
  <section id='thank-you'>
<h1>Thank You!</h1>

<a href="http://bit.ly/k8s-kubectl"><h5 class='fragment grow'>bit.ly/k8s-kubectl</h5></a>
  </section>
  -->
    <section id='next-steps'>
    <h3>Congratulations on completing:</h3>
    <p><a href="http://bit.ly/k8s-kubectl"><b>Kubernetes Command-Line Basics with <code>kubectl</code></b><h5 class='fragment grow'><code>bit.ly/k8s-kubectl</code></h5></a></p>
    <br/>
    <h4><i>Next Steps</i></h4>
    <p>Continue learning with other <a href="http://bit.ly/k8s-workshops"><code>k8s-workshops</code></a>:</p> 
    <ol>
      <li><a href="http://bit.ly/k8s-miniarch"><b>Kubernetes Architecture (adapted for <code>minikube</code>)</b><br/>bit.ly/k8s-miniarch</a></li>
      <li><a href="http://bit.ly/k8s-minidev"><b>Local Development with <code>minikube</code></b><br/><span style='font-size:smaller;'>bit.ly/k8s-minidev</span></a></li>

      <!-- <li><a href="http://bit.ly/operatorpattern"><b>Extending Kubernetes with the Operator Pattern</b><br/><span style='font-size:smaller;'>bit.ly/operatorpattern</span></a></li> -->
    </ol>
  </section>      

</section>