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Fargo-Moorhead drone racers discover speed thrills

5/25/2018

Listen Story audio

May 24, 2018

4min 38sec

Maybe it’s the rush of flying while your feet are firmly planted on the ground, or the sensation of hurtling across the sky, knowing it’s not the end of the world if you crash.

Whatever the motivation, drone racing is taking off into a rapidly growing worldwide sport driven by pilots, thrill seekers and tinkerers in places like Fargo-Moorhead.

“It’s the closest you can get to, I guess, actual racing in cars and stuff — without the problem of dying, possibly,” drone racer Gary Ferguson said during a recent meetup at a Moorhead park.

The pilots stand on the grass but they feel like they’re flying the tiny aircraft that just took off. They wear special goggles — all they see is the video from a camera on board their drone. The idea is to get through the course as many times as possible in two minutes. Crashes are common, but repairs are quick and they’re back racing.

Heads bob and turn and fingers work controls as they try to fly their drones through gates and around flags on a course about the size of a football field.

Drone racing is taking off into a rapidly growing worldwide sport driven by pilots, thrill seekers and tinkerers in places like Fargo-Moorhead. Courtesy of Quad Squad Fargo-Moorhead

“OK, you come to the first gate like this, then you fly over the second gate, and then come back from the other way,” Ian McIntyre said as he explained the course layout to another racer as they flew their crafts and watched the drone video.

“If you’ve ever thought to yourself, you know, what would it be like to be a bird flying around the trees and over the landscape, that’s what this gives you,” said Tony Bjerke, who started Quad Squad Fargo-Moorhead a couple of years ago. The name refers to the four-propeller copters the racers fly.

The machines are about a foot across and they zip around the course so quickly they’re hard to follow.

“You know, it feels like you’re doing 100 miles an hour,” he said. “Well, guess what, you’re actually doing 100 miles an hour because these things fly that fast.”

‘Tinkerers at heart’

Pilot Tony Bjerke of Fargo prepares his drone and related gear for a race. — Pilot Tony Bjerke of Fargo, N.D., prepares his drone and related gear for a race. Bjerke and other racers say it costs roughly $1,200 for all the equipment to get started in the sport, but many spend a lot more. Ann Arbor Miller for MPR News

Bjerke launched the group a couple of years ago after he started flying drones and learned about drone racing leagues, which have exploded in recent years. MultiGP, which calls itself the largest professional drone racing league in the world, says it has more than 1,250 chapters and 23,000 pilots worldwide.

Sponsors paid for the gates and flags the Moorhead club uses to set up race courses. Companies are increasingly interested in sponsoring drone racers and putting up prize money for regional and national events

The sport’s grown steadily in Fargo-Moorhead as drone enthusiasts hear about the club. There are about three dozen members currently, mostly men with a few women.

A pair of drones dot the sky during a race. Ann Arbor Miller for MPR News

They have a range of ages and experience. Some are clearly nerds who love to build and fix and improvise with technology. But they all seem transfixed by the experience of feeling like they are flying.

“Most of us are all tinkerers at heart,” said Bjerke. “This is just another thing to tinker with and wrench-on and do that stuff.”

The Fargo-Moorhead club members race against each other, but also race clubs in the Twin Cities, Duluth and Grand Forks, N.D. Tens of thousands of drone racers are registered with drone racing leagues across the country. The ultimate prize is a national championship.

Members of the FM Quad Squad use drones with four propellers for races. — Members of the FM Quad Squad use drones with four propellers for races like those held most Thursday evenings at M.B. Johnson Park. Ann Arbor Miller for MPR News

The racers say it costs about $1,200 for all the gear to get started in the sport, but many spend a lot more. For some, it’s as much about building as it is about racing.

‘Two minutes out of the wheelchair’

Ferguson flew radio controlled aircraft for 25 years. It could be an expensive hobby. A crash could wreck a $1,500 aircraft. When his drone crashes, he usually just picks it up, checks for broken propellers and is ready to fly again. Everything he needs is in a backpack.

Ferguson is an accomplished drone flyer, but he says he can’t keep up with kids who grew up on video games.

“The speed at which they fly these things is just mind-blowing, I can’t even follow them,” he said. You know, it’s watching their video and just going, ‘Yeah, I’m out.’ I’m probably mediocre, but it’s just so much fun.”

Pilot Shawn Spears of Moorhead, Minn., maneuvers his drone during a race. — Pilot Shawn Spears of Moorhead maneuvers his drone during a race. Ann Arbor Miller for MPR News

McIntyre has raced radio controlled cars or planes before, but said the the virtual experience of racing a drone from the cockpit with video goggles is a tremendous adrenaline rush.

“It’s ridiculous how a little tiny toy basically can give you the shakes,” he said. “You’re saying in your mind, ‘Relax. Just fly. Stop being an idiot and shaking. Just fly.’ It’s so much fun. It’s, it’s racing.”

[embedded content]

One of the racers hunched over his controller on this evening thought he’d never race again.

Darrin Devine grew up racing motorcycles,”and then I broke my neck, became a quadriplegic doing motor cross races.

“Racing has always been something I enjoy doing a lot and it’s absolutely like being racing again,” he said of the drone contests. “You get the same type of adrenaline rush. It’s the two minutes out of the wheelchair, having fun being just another racer.”

When racers were called to the starting line, Devine wheeled away, ready to zip through the sky for another two minutes of adrenaline fueled freedom.

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The EU General Data Protection Regulation (GDPR) and us

5/25/2018

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Fiber Optic Globe It’s been an interesting week – my Pre-K kiddo “graduated” yesterday and will be attending a Kudzu-league kindergarten in the fall, the temperature hit 99 degrees in May, and the European Union General Data Protection Regulation went into effect and the LA Times, among others, is now not serving content to the EU.

At Pocketables, we’d pretty much ignored the GDPR as we’re not based in the EU, we don’t store anything other than what you give us, we don’t sell or process anyone’s data, the comment system is controlled by a company called Disqus which is compliant, our servers are located in the US in Texas, the software stores IP information which every website in the world does for basic diagnostic logging but gets deleted after a few days, every damned site on the internet uses cookies and making you click that everywhere is lamosity in the extreme.

I can’t imagine WordPress is currently GDPR compliant out of the box, but I’m sure there’ll be a plugin or update for a user to get their data (we however don’t have user accounts, Disqus handles that.)

So, you may have noticed a full page Disqus popup, there’s the EU compliance there. I don’t know how they’re going to attempt to say they comply with the right to be digitally forgotten (when you reach the point where your neo-nazi past has become a little troublesome with your desire employment,) but there’s that aspect.

I’d heard it reported on the news today that a lot of these companies had been blocked in the EU, but that appears to not be the case. They’ve just ceased serving up content as they’re liable to multi-million dollar fines if they continue operating in (or selling selling ads/info to,) the EU. Begs the question what information were they selling?

While I fully plan to use all data collected from you guys for nefarious purposes, that is for another day. I’m too busy today with the 5yo in tow as we have no kidsitting for a week for her.

What I find interesting here is that the GDPR looks like it is going to be next to unenforceable, much like the US’s can-spam act. Oh, you’ve got that one major player who admitted violating the rules? Well then… let’s have at them.

Incoherent writing caused by 5yo in office.

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Kubernetes recipes: Maintenance and troubleshooting

5/25/2018

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Mindful instruction (source: Magnus D on Flickr)

In this chapter, you will find recipes that deal with both app-level and cluster-level maintenance. We cover various aspects of troubleshooting, from debugging pods and containers, to testing service connectivity, interpreting a resourceâ€™s status, and node maintenance. Last but not least, we look at how to deal with etcd, the Kubernetes control plane storage component. This chapter is relevant for both cluster admins and app developers.

Enabling Autocomplete for kubectl

Problem

It is cumbersome to type full commands and arguments for the kubectl command, so you want an autocomplete function for it.

Solution

Enable autocompletion for kubectl.

For Linux and the bash shell, you can enable kubectl autocompletion in your current shell using the following command:

$ source

For other operating systems and shells, please check the documentation.

Removing a Pod from a Service

Problem

You have a well-defined service (see not available) backed by several pods. But one of the pods is misbehaving, and you would like to take it out of the list of endpoints to examine it at a later time.

Solution

Relabel the pod using the --overwrite optionâ€”this will allow you to change the value of the run label on the pod. By overwriting this label, you can ensure that it will not be selected by the service selector (not available) and will be removed from the list of endpoints. At the same time, the replica set watching over your pods will see that a pod has disappeared and will start a new replica.

To see this in action, start with a straightforward deployment generated with kubectl run (see not available):

$ kubectl run nginx --image nginx --replicas 4

When you list the pods and show the label with key run, youâ€™ll see four pods with the value nginx (run=nginx is the label that is automatically generated by the kubectl run command):

$ kubectl get pods -Lrun
NAME                     READY     STATUS            RESTARTS   AGE       RUN
nginx-d5dc44cf7-5g45r    1/1       Running           0          1h        nginx
nginx-d5dc44cf7-l429b    1/1       Running           0          1h        nginx
nginx-d5dc44cf7-pvrfh    1/1       Running           0          1h        nginx
nginx-d5dc44cf7-vm764    1/1       Running           0          1h        nginx

You can then expose this deployment with a service and check the endpoints, which correspond to the IP addresses of each pod:

$ kubectl expose deployments nginx --port 80

$ kubectl get endpoints
NAME         ENDPOINTS                                                 AGE
nginx        172.17.0.11:80,172.17.0.14:80,172.17.0.3:80 + 1 more...   1h

Moving the first pod out of the service traffic via relabeling is done with a single command:

$ kubectl label pods nginx-d5dc44cf7-5g45r run=notworking --overwrite

Tip

To find the IP address of a pod, you can list the podâ€™s manifest in JSON and run a JQuery query:

$ kubectl get pods nginx-d5dc44cf7-5g45r -o json | 
  jq -r .status.podIP172.17.0.3

You will see a brand new pod appear with the label run=nginx, and you will see that your nonworking pod still exists but no longer appears in the list of service endpoints:

$ kubectl get pods -Lrun
NAME                     READY     STATUS        RESTARTS   AGE       RUN
nginx-d5dc44cf7-5g45r    1/1       Running       0          21h       notworking
nginx-d5dc44cf7-hztlw    1/1       Running       0          21s       nginx
nginx-d5dc44cf7-l429b    1/1       Running       0          5m        nginx
nginx-d5dc44cf7-pvrfh    1/1       Running       0          5m        nginx
nginx-d5dc44cf7-vm764    1/1       Running       0          5m        nginx

$ kubectl describe endpoints nginx
Name:         nginx
Namespace:    default
Labels:       run=nginx
Annotations:  
Subsets:
  Addresses:          172.17.0.11,172.17.0.14,172.17.0.19,172.17.0.7
...

Accessing a ClusterIP Service Outside the Cluster

Problem

You have an internal service that is causing you trouble and you want to test that it is working well locally without exposing the service externally.

Solution

Use a local proxy to the Kubernetes API server with kubectl proxy.

Letâ€™s assume that you have created a deployment and a service as described in Removing a Pod from a Service. You should see an nginx service when you list the services:

$ kubectl get svc
NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE
nginx        ClusterIP   10.109.24.56           80/TCP    22h

This service is not reachable outside the Kubernetes cluster. However, you can run a proxy in a separate terminal and then reach it on localhost.

Start by running the proxy in a separate terminal:

$ kubectl proxy
Starting to serve on 127.0.0.1:8001

Tip

You can specify the port that you want the proxy to run on with the --port option.

In your original terminal, you can then use your browser or curl to access the application exposed by your service. Note the specific path to the service; it contains a /proxy part. Without this, you get the JSON object representing the service:

$ curl http://localhost:8001/api/v1/proxy/namespaces/default/services/nginx/

Welcome to nginx!

...

Note

Note that you can now also access the entire Kubernetes API over localhost using curl.

Understanding and Parsing Resource Statuses

Problem

You want to react based on the status of a resourceâ€”say, a podâ€”in a script or in another automated environment like a CI/CD pipeline.

Solution

Use kubectl get $KIND/$NAME -o json and parse the JSON output using one of the two methods described here.

If you have the JSON query utility jq installed, you can use it to parse the resource status. Letâ€™s assume you have a pod called jump and want to know what Quality of Service (QoS) class¹ the pod is in:

$ kubectl get po/jump -o json | jq --raw-output .status.qosClass
BestEffort

Note that the --raw-output argument for jq will show the raw value and that .status.qosClass is the expression that matches the respective subfield.

Another status query could be around the events or state transitions:

$ kubectl get po/jump -o json | jq .status.conditions
[
  {
    "lastProbeTime": null,
    "lastTransitionTime": "2017-08-28T08:06:19Z",
    "status": "True",
    "type": "Initialized"
  },
  {
    "lastProbeTime": null,
    "lastTransitionTime": "2017-08-31T08:21:29Z",
    "status": "True",
    "type": "Ready"
  },
  {
    "lastProbeTime": null,
    "lastTransitionTime": "2017-08-28T08:06:19Z",
    "status": "True",
    "type": "PodScheduled"
  }
]

Of course, these queries are not limited to podsâ€”you can apply this technique to any resource. For example, you can query the revisions of a deployment:

$ kubectl get deploy/prom -o json | jq .metadata.annotations
{
  "deployment.kubernetes.io/revision": "1"
}

Or you can list all the endpoints that make up a service:

$ kubectl get ep/prom-svc -o json | jq '.subsets'
[
  {
    "addresses": [
      {
        "ip": "172.17.0.4",
        "nodeName": "minikube",
        "targetRef": {
          "kind": "Pod",
          "name": "prom-2436944326-pr60g",
          "namespace": "default",
          "resourceVersion": "686093",
          "uid": "eee59623-7f2f-11e7-b58a-080027390640"
        }
      }
    ],
    "ports": [
      {
        "port": 9090,
        "protocol": "TCP"
      }
    ]
  }
]

Now that youâ€™ve seen jq in action, letâ€™s move on to a method that doesnâ€™t require external toolingâ€”that is, the built-in feature of using Go templates.

The Go programming language defines templates in a package called text/template that can be used for any kind of text or data transformation, and kubectl has built-in support for it. For example, to list all the container images used in the current namespace, do this:

$ kubectl get pods -o go-template 
          --template="{{range .items}}{{range .spec.containers}}{{.image}} 
          {{end}}{{end}}"
busybox prom/prometheus

Debugging Pods

Problem

You have a situation where a pod is either not starting up as expected or fails after some time.

Solution

To systematically discover and fix the cause of the problem, enter an OODA loop:

Observe. What do you see in the container logs? What events have occurred? How is the network connectivity?
Orient. Formulate a set of plausible hypothesesâ€”stay as open-minded as possible and donâ€™t jump to conclusions.
Decide. Pick one of the hypotheses.
Act. Test the hypothesis. If itâ€™s confirmed, youâ€™re done; otherwise, go back to step 1 and continue.

Letâ€™s have a look at a concrete example where a pod fails. Create a manifest called unhappy-pod.yaml with this content:

apiVersion:       extensions/v1beta1
kind:             Deployment
metadata:
  name:           unhappy
spec:
  replicas:       1
  template:
    metadata:
      labels:
        app:      nevermind
    spec:
      containers:
      - name:     shell
        image:    busybox
        command:
        - "sh"
        - "-c"
        - "echo I will just print something here and then exit"

Now when you launch that deployment and look at the pod it creates, youâ€™ll see itâ€™s unhappy:

$ kubectl create -f unhappy-pod.yaml
deployment "unhappy" created

$ kubectl  get po
NAME                       READY     STATUS             RESTARTS   AGE
unhappy-3626010456-4j251   0/1       CrashLoopBackOff   1          7s

$ kubectl describe po/unhappy-3626010456-4j251
Name:           unhappy-3626010456-4j251
Namespace:      default
Node:           minikube/192.168.99.100
Start Time:     Sat, 12 Aug 2017 17:02:37 +0100
Labels:         app=nevermind
                pod-template-hash=3626010456
Annotations:    kubernetes.io/created-by={"kind":"SerializedReference","apiVersion":
"v1","reference":{"kind":"ReplicaSet","namespace":"default","name":
"unhappy-3626010456","uid":
"a9368a97-7f77-11e7-b58a-080027390640"...
Status:         Running
IP:             172.17.0.13
Created By:     ReplicaSet/unhappy-3626010456
Controlled By:  ReplicaSet/unhappy-3626010456
...
Conditions:
  Type          Status
  Initialized   True
  Ready         False
  PodScheduled  True
Volumes:
  default-token-rlm2s:
    Type:       Secret (a volume populated by a Secret)
    SecretName: default-token-rlm2s
    Optional:   false
QoS Class:      BestEffort
Node-Selectors: 
Tolerations:    
Events:
  FirstSeen   ...   Reason                  Message
  ---------   ...   ------                  -------
  25s         ...   Scheduled               Successfully assigned
                                            unhappy-3626010456-4j251 to minikube
  25s         ...   SuccessfulMountVolume   MountVolume.SetUp succeeded for
                                            volume "default-token-rlm2s"
  24s         ...   Pulling                 pulling image "busybox"
  22s         ...   Pulled                  Successfully pulled image "busybox"
  22s         ...   Created                 Created container
  22s         ...   Started                 Started container
  19s         ...   BackOff                 Back-off restarting failed container
  19s         ...   FailedSync              Error syncing pod

As you can see, Kubernetes considers this pod as not ready to serve traffic as it encountered an â€œerror syncing pod.â€

Another way to observe this is using the Kubernetes dashboard to view the deployment (Figure 1), as well as the supervised replica set and the pod (Figure 2).

Screen Shot Of Deployment In Error State — Figure 1. Screenshot of deployment in error state

Screen Shot Of Pod In Error State — Figure 2. Screenshot of pod in error state

Discussion

An issue, be it a pod failing or a node behaving strangely, can have many different causes. Here are some things youâ€™ll want to check before suspecting software bugs:

Is the manifest correct? Check with the Kubernetes JSON schema.
Does the container run standalone, locally (that is, outside of Kubernetes)?
Can Kubernetes reach the container registry and actually pull the container image?
Can the nodes talk to each other?
Can the nodes reach the master?
Is DNS available in the cluster?
Are there sufficient resources available on the nodes?
Did you restrict the containerâ€™s resource usage?

Getting a Detailed Snapshot of the Cluster State

Problem

You want to get a detailed snapshot of the overall cluster state for orientation, auditing, or troubleshooting purposes.

Solution

Use the kubectl cluster-info dump command. For example, to create a dump of the cluster state in a subdirectory cluster-state-2017-08-13, do this:

$ kubectl cluster-info dump --all-namespaces 
  --output-directory=$PWD/cluster-state-2017-08-13

$ tree ./cluster-state-2017-08-13
.
â”œâ”€â”€ default
â”‚   â”œâ”€â”€ cockroachdb-0
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ cockroachdb-1
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ cockroachdb-2
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ daemonsets.json
â”‚   â”œâ”€â”€ deployments.json
â”‚   â”œâ”€â”€ events.json
â”‚   â”œâ”€â”€ jump-1247516000-sz87w
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ nginx-4217019353-462mb
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ nginx-4217019353-z3g8d
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ pods.json
â”‚   â”œâ”€â”€ prom-2436944326-pr60g
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ replicasets.json
â”‚   â”œâ”€â”€ replication-controllers.json
â”‚   â””â”€â”€ services.json
â”œâ”€â”€ kube-public
â”‚   â”œâ”€â”€ daemonsets.json
â”‚   â”œâ”€â”€ deployments.json
â”‚   â”œâ”€â”€ events.json
â”‚   â”œâ”€â”€ pods.json
â”‚   â”œâ”€â”€ replicasets.json
â”‚   â”œâ”€â”€ replication-controllers.json
â”‚   â””â”€â”€ services.json
â”œâ”€â”€ kube-system
â”‚   â”œâ”€â”€ daemonsets.json
â”‚   â”œâ”€â”€ default-http-backend-wdfwc
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ deployments.json
â”‚   â”œâ”€â”€ events.json
â”‚   â”œâ”€â”€ kube-addon-manager-minikube
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ kube-dns-910330662-dvr9f
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ kubernetes-dashboard-5pqmk
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ nginx-ingress-controller-d2f2z
â”‚   â”‚   â””â”€â”€ logs.txt
â”‚   â”œâ”€â”€ pods.json
â”‚   â”œâ”€â”€ replicasets.json
â”‚   â”œâ”€â”€ replication-controllers.json
â”‚   â””â”€â”€ services.json
â””â”€â”€ nodes.json

Adding Kubernetes Worker Nodes

Problem

You need to add a worker node to your Kubernetes cluster.

Solution

Provision a new machine in whatever way your environment requires (for example, in a bare-metal environment you might need to physically install a new server in a rack, in a public cloud setting you need to create a new VM, etc.), and then install the three components that make up a Kubernetes worker node:

kubelet

This is the node manager and supervisor for all pods, no matter if theyâ€™re controlled by the API server or running locally, such as static pods. Note that the kubelet is the final arbiter of what pods can or cannot run on a given node, and takes care of:

Reporting node and pod statuses to the API server.
Periodically executing liveness probes.
Mounting the pod volumes and downloading secrets.
Controlling the container runtime (see the following).

Container runtime

This is responsible for downloading container images and running the containers. Initially, this was hardwired to the Docker engine, but nowadays it is a pluggable system based on the Container Runtime Interface (CRI), so you can, for example, use CRI-O rather than Docker.

kube-proxy

This process dynamically configures iptables rules on the node to enable the Kubernetes service abstraction (redirecting the VIP to the endpoints, one or more pods representing the service).

The actual installation of the components depends heavily on your environment and the installation method used (cloud, kubeadm, etc.). For a list of available options, see the kubelet reference and kube-proxy reference.

Discussion

Worker nodes, unlike other Kubernetes resources such as a deployments or services, are not directly created by the Kubernetes control plane but only managed by it. That means when Kubernetes creates a node, it actually only creates an object that represents the worker node. It validates the node by health checks based on the nodeâ€™s metadata.name field, and if the node is validâ€”that is, all necessary components are runningâ€”it is considered part of the cluster; otherwise, it will be ignored for any cluster activity until it becomes valid.

Draining Kubernetes Nodes for Maintenance

Problem

You need to carry out maintenance on a nodeâ€”for example, to apply a security patch or upgrade the operating system.

Solution

Use the kubectl drain command. For example, to do maintenance on node 123-worker:

$ kubectl drain 123-worker

When you are ready to put the node back into service, use kubectl uncordon 123-worker, which will make the node schedulable again.

Discussion

What the kubectl drain command does is to first mark the specified node un-schedulable to prevent new pods from arriving (essentially a kubectl cordon). Then it evicts the pods if the API server supports eviction. Otherwise, it will use normal kubectl delete to delete the pods. The Kubernetes docs have a concise sequence diagram of the steps, reproduced in Figure 3.

The kubectl drain command evicts or deletes all pods except mirror pods (which cannot be deleted through the API server). For pods supervised by a DaemonSet, drain will not proceed without using --ignore-daemonsets, and regardless it will not delete any DaemonSet-managed podsâ€”those pods would be immediately replaced by the DaemonSet controller, which ignores unschedulable markings.

Warning

drain waits for graceful termination, so you should not operate on this node until the kubectl drain command has completed. Note that kubectl drain $NODE --force will also evict pods not managed by an RC, RS, job, DaemonSet, or StatefulSet.

Managing etcd

Problem

You need to access etcd to back it up or verify the cluster state directly.

Solution

Get access to etcd and query it, either using curl or etcdctl. For example, in the context of Minikube (with jq installed):

$ minikube ssh

$ curl 127.0.0.1:2379/v2/keys/registry | jq .
{
  "action": "get",
  "node": {
    "key": "/registry",
    "dir": true,
    "nodes": [
      {
        "key": "/registry/persistentvolumeclaims",
        "dir": true,
        "modifiedIndex": 241330,
        "createdIndex": 241330
      },
      {
        "key": "/registry/apiextensions.k8s.io",
        "dir": true,
        "modifiedIndex": 641,
        "createdIndex": 641
      },
...

This technique can be used in environments where etcd is used with the v2 API.

Discussion

In Kubernetes, etcd is a component of the control plane. The API server (see not available) is stateless and the only Kubernetes component that directly communicates with etcd, the distributed storage component that manages the cluster state. Essentially, etcd is a key/value store; in etcd2 the keys formed a hierarchy, but with the introduction of etcd3 this was replaced with a flat model (while maintaining backwards compatibility concerning hierarchical keys).

Note

Up until Kubernetes 1.5.2 we used etcd2, and from then on we switched to etcd3. In Kubernetes 1.5.x, etcd3 is still used in v2 API mode and going forward this is changing to the etcd v3 API with v2 being deprecated soon. Though from a developerâ€™s point of view this doesnâ€™t have any implications, because the API server takes care of abstracting the interactions away, as an admin you want to pay attention to which etcd version is used in which API mode.

In general, itâ€™s the responsibility of the cluster admin to manage etcdâ€”that is, to upgrade it and make sure the data is backed up. In certain environments where the control plane is managed for you, such as in Google Kubernetes Engine, you cannot access etcd directly. This is by design, and thereâ€™s no workaround for it.

Four short links: 25 May 2018

5/25/2018

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Four short links

U.S. Criminal Probe into Bitcoin Manipulation — also in the news: $1.2 billion of cryptocurrency stolen since 2017.
Bill Gates on Platforms — A platform is when the economic value of everybody that uses it exceeds the value of the company that creates it. Then it’s a platform. (via Stratechery)
Inside the 76477 Space Invaders Sound Chip — this is fascinating! The 76477 is primarily analog—most control signals are analog, the chip doesn’t have digital control registers, and most sounds are generated from analog circuits—but about a third of the chip’s area is digital logic.
Smooth Life — Conway’s Game of Life on a continuous domain. See also Game of Life for Curved Surfaces and accompanying video. (via lobste.rs)

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Designing our friendly robot companions isnt about the AI

5/25/2018

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In this video excerpt, Ben Brown explores why designing for messaging will become a discipline as important as responsive design, incorporating skills as diverse as copywriting, business analytics, and API programming.

Watch the full video on O’Reilly’s learning platform.

Ben Brown is a veteran software designer and developer. Over 20 years, he’s been involved in almost every aspect of technology, from infrastructure to financing. He cofounded XOXCO in 2008 to offer product design as a service.

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Kubernetes recipes: Maintenance and troubleshooting

Enabling Autocomplete for kubectl

Problem

Solution

See Also

Removing a Pod from a Service

Problem

Solution

Tip

Accessing a ClusterIP Service Outside the Cluster

Problem

Solution

Tip

Note

Understanding and Parsing Resource Statuses

Problem

Solution

See Also

Debugging Pods

Problem

Solution

Discussion

See Also

Getting a Detailed Snapshot of the Cluster State

Problem

Solution

Adding Kubernetes Worker Nodes

Problem

Solution

Discussion

See Also

Draining Kubernetes Nodes for Maintenance

Problem

Solution

Discussion

Warning

See Also

Managing etcd

Problem

Solution

Discussion

Note

See Also

Four short links: 25 May 2018

Designing our friendly robot companions isnt about the AI

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