Minimum viable Kubernetes

I remember sitting in the audience at the first Dockercon in 2014 when Google announced Kubernetes and thinking “what kind of a name is that?”. In the intervening years, Kubernetes, or k8s for short, has battled it out with Cattle and Docker swarm and emerged as the last orchestrator standing.

I’ve been watching this happen but have been procrastinating on learning it because from a distance it looks hella complicated. Recently I decided to rip off the bandaid and set myself the challenge of getting a single container running in k8s.

While every major cloud provider is offering k8s, so far Google looks to be the easiest to get started with. So what does it take to get a container running on Google Cloud?

First some assumptions: you’ve installed the gcloud command (I used this) with the alpha commands, and you have a GCP account, and you’ve logged in with gcloud auth login.

If you have that sorted, let’s create a project.

mike@sleepycat:~$ gcloud projects create --name projectfoo
No project id provided.

Use [projectfoo-208401] as project id (Y/n)?  

Create in progress for [https://cloudresourcemanager.googleapis.com/v1/projects/projectfoo-208401].
Waiting for [operations/cp.4790935341316997740] to finish...done.

With a project created we need to enable billing for it, so Google can charge you for the compute resources Kubernetes uses.

                                                                                                                                      
mike@sleepycat:~$ gcloud alpha billing projects link projectfoo-208401 --billing-account 0X0X0X-0X0X0X-0X0X0X
billingAccountName: billingAccounts/0X0X0X-0X0X0X-0X0X0X
billingEnabled: true
name: projects/projectfoo-208401/billingInfo
projectId: projectfoo-208401

Next we need to enable the Kubernetes Engine API for our new project.

mike@sleepycat:~$ gcloud services --project=projectfoo-208401 enable container.googleapis.com
Waiting for async operation operations/tmo-acf.445bb50c-cf7a-4477-831c-371fea91ddf0 to complete...
Operation finished successfully. The following command can describe the Operation details:
 gcloud services operations describe operations/tmo-acf.445bb50c-cf7a-4477-831c-371fea91ddf0

With that done, we are free to fire up a Kubernetes cluster. There is a lot going on here, more than you need, but it’s good to be able to see some of the options available. Probably the only ones to care about initially are the zone and the machine-type.

mike@sleepycat:~$ gcloud beta container --project=projectfoo-208401 clusters create "projectfoo" --zone "northamerica-northeast1-a" --username "admin" --cluster-version "1.8.10-gke.0" --machine-type "f1-micro" --image-type "COS" --disk-type "pd-standard" --disk-size "100" --scopes "https://www.googleapis.com/auth/compute","https://www.googleapis.com/auth/devstorage.read_only","https://www.googleapis.com/auth/logging.write","https://www.googleapis.com/auth/monitoring","https://www.googleapis.com/auth/servicecontrol","https://www.googleapis.com/auth/service.management.readonly","https://www.googleapis.com/auth/trace.append" --num-nodes "3" --enable-cloud-logging --enable-cloud-monitoring --addons HorizontalPodAutoscaling,HttpLoadBalancing,KubernetesDashboard --enable-autoupgrade --enable-autorepair
This will enable the autorepair feature for nodes. Please see
https://cloud.google.com/kubernetes-engine/docs/node-auto-repair for more
information on node autorepairs.

This will enable the autoupgrade feature for nodes. Please see
https://cloud.google.com/kubernetes-engine/docs/node-management for more
information on node autoupgrades.

Creating cluster projectfoo...done.                                                                                                                                                                         
Created [https://container.googleapis.com/v1beta1/projects/projectfoo-208401/zones/northamerica-northeast1-a/clusters/projectfoo].
To inspect the contents of your cluster, go to: https://console.cloud.google.com/kubernetes/workload_/gcloud/northamerica-northeast1-a/projectfoo?project=projectfoo-208401
kubeconfig entry generated for projectfoo.
NAME        LOCATION                   MASTER_VERSION  MASTER_IP     MACHINE_TYPE  NODE_VERSION  NUM_NODES  STATUS
projectfoo  northamerica-northeast1-a  1.8.10-gke.0    35.203.8.163  f1-micro      1.8.10-gke.0  3          RUNNING

With that done we can take a quick peek at what that last command created: a Kubernetes cluster on three f1-micro VMs.

mike@sleepycat:~$ gcloud compute instances --project=projectfoo-208401 list
NAME                                       ZONE                       MACHINE_TYPE  PREEMPTIBLE  INTERNAL_IP  EXTERNAL_IP    STATUS
gke-projectfoo-default-pool-190d2ac3-59hg  northamerica-northeast1-a  f1-micro                   10.162.0.4   35.203.87.122  RUNNING
gke-projectfoo-default-pool-190d2ac3-lbnk  northamerica-northeast1-a  f1-micro                   10.162.0.2   35.203.78.141  RUNNING
gke-projectfoo-default-pool-190d2ac3-pmsw  northamerica-northeast1-a  f1-micro                   10.162.0.3   35.203.91.206  RUNNING

Let’s put those f1-micro‘s to work. We are going to use the kubectl run command to run a simple helloworld container that just has the basic output of create-react-app in it.

mike@sleepycat:~$ kubectl run projectfoo --image mikewilliamson/helloworld --port 3000
deployment "projectfoo" created

The result of that is the helloworld container, running inside a pod, inside a replica set inside a deployment, which of course is running inside a VM on Google Cloud. All that’s needed now is to map the port the container is listening on (3000) to port 80 so we can talk to it from the outside world.

mike@sleepycat:~$ kubectl expose deployment projectfoo --type LoadBalancer --port 80 --target-port 3000
service "projectfoo" exposed

This creates a LoadBalancer service, and eventually we get allocated our own IP.

mike@sleepycat:~$ kubectl get services
NAME         TYPE           CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP      10.59.240.1    <none>        443/TCP        3m
projectfoo   LoadBalancer   10.59.245.55   <pending>     80:32184/TCP   34s
mike@sleepycat:~$ kubectl get services
NAME         TYPE           CLUSTER-IP     EXTERNAL-IP      PORT(S)        AGE
kubernetes   ClusterIP      10.59.240.1    <none>           443/TCP        4m
projectfoo   LoadBalancer   10.59.245.55   35.203.123.204   80:32184/TCP   1m

Then we can use our newly allocated IP and talk to our container. The moment of truth!

mike@sleepycat:~$ curl 35.203.123.204
<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1,shrink-to-fit=no"><meta name="theme-color" content="#000000"><link rel="manifest" href="/manifest.json"><link rel="shortcut icon" href="/favicon.ico"><title>React App</title><link href="/static/css/main.c17080f1.css" rel="stylesheet"></head><body><noscript>You need to enable JavaScript to run this app.</noscript><div id="root"></div><script type="text/javascript" src="/static/js/main.61911c33.js"></script></body></html>

After you’ve taken a moment to marvel at the layers of abstractions involved here, it’s worth remembering that you probably don’t want this stuff hanging around if you aren’t really using it, otherwise you’re going to regret connecting your billing information.

mike@sleepycat:~$ gcloud container --project projectfoo-208401 clusters delete projectfoo
The following clusters will be deleted.
 - [projectfoo] in [northamerica-northeast1-a]

Do you want to continue (Y/n)?  y

Deleting cluster projectfoo...done.                                                                                                                                                                         
Deleted [https://container.googleapis.com/v1/projects/projectfoo-208401/zones/northamerica-northeast1-a/clusters/projectfoo].
mike@sleepycat:~$ gcloud projects delete projectfoo-208401
Your project will be deleted.

Do you want to continue (Y/n)?  y

Deleted [https://cloudresourcemanager.googleapis.com/v1/projects/projectfoo-208401].

You can undo this operation for a limited period by running:
  $ gcloud projects undelete projectfoo-208401

There is a lot going on here, and since this is new territory, much of it doesn’t mean lots to me yet. What’s exciting to me is finally being able to get a toe-hold on an otherwise pretty intimidating subject.

Having finally started working with it, I have to say both the kubectl and gcloud CLI tools are thoughtfully designed and pretty intuitive, and Google’s done a nice job making a lot of stuff happen in just a few approachable commands. I’m excited to dig in further.

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