Deploying to Kubernetes

Why Kubernetes

• We can learn one way to deploy applications and re-use those skills on other projects. So rather than learning the Google, Heroku, AWS way to deploy applications we learn the Kubernetes way of deploying applications. We will be cloud agnostic.

• Kubernetes will handle just about every deployment scenario you can think of.

• We can test our deployments on our local machines using a tool called kind.

• The Kubernetes way of application deployment will be a useful skills for the next decade or more.

• For some projects we need to deploy On Prem and more and more companies are providing Kubernetes as a way to deploy applications in house.

Setting up a local cluster with Kind

Kind Will create a tiny Kubernetes cluster in our docker environment. We've pre-installed kind in our devcontainer so let's create a cluster.

$ kind get clusters
No kind clusters found.

Create a temporary file called config.yaml.

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
networking:
  # If we don't do this, then we can't connect on linux
  apiServerAddress: "0.0.0.0"
kubeadmConfigPatchesJSON6902:
- group: kubeadm.k8s.io
  version: v1beta3
  kind: ClusterConfiguration
  patch: |
    - op: add
      path: /apiServer/certSANs/-
      value: host.docker.internal

Normally kind is easier to use than this but because we are in a devcontainer we have to use some special config.

kind create cluster --name nails-cluster --config=config.yaml

kind create cluster --name nails-cluster
Creating cluster "nails-cluster" ...
 ✓ Ensuring node image (kindest/node:v1.25.3) 🖼
 ✓ Preparing nodes 📦  
 ✓ Writing configuration 📜 
 ✓ Starting control-plane 🕹️ 
 ✓ Installing CNI 🔌 
 ✓ Installing StorageClass 💾 
Set kubectl context to "kind-nails-cluster"
You can now use your cluster with:

kubectl cluster-info --context kind-nails-cluster

Have a question, bug, or feature request? Let us know! https://kind.sigs.k8s.io/#community 🙂

Interacting with our cluster (Windows and MacOs)

Kubernetes is administered with a command called kubectl let's configure kubectl so that it can access our cluster.

$ kind export kubeconfig --name nails-cluster
Set kubectl context to "kind-nails-cluster"

We need to do a little trick so that kubectl can see the cluster when running inside our devcontainer. Run the following.

sed -i 's/0.0.0.0/host.docker.internal/g' $HOME/.kube/config

And now we can use kubectl to see what pods we have in our cluster.

$ kubectl get pods
No resources found in default namespace.

Interacting with our cluster in Linux

Add the following to .devcontainer/docker-compose.yml

    extra_hosts:
      - "host.docker.internal:host-gateway"

And rebuild your devcontainer

$ kind export kubeconfig --name nails-cluster
Set kubectl context to "kind-nails-cluster"

We need to do a little trick so that kubectl can see the cluster when running inside our devcontainer. Run the following.

sed -i 's/0.0.0.0/host.docker.internal/g' $HOME/.kube/config

And now we can use kubectl to see what pods we have in our cluster.

$ kubectl get pods
No resources found in default namespace.