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00-setup-kubectl-linux.md

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Setup kubectl

It is assumed that you are provided with a kubernetes cluster by the instructor. Before you are able to do anything on the cluster, you need to be able to talk to this cluster from/using your computer. kubectl - short for Kubernetes Controller - is the command line tool to talk to a Kubernetes cluster. To get that on your computer, you download it in the following way:

$ curl -LO https://storage.googleapis.com/kubernetes-release/release/v1.7.5/bin/linux/amd64/kubectl && chmod +x ./kubectl && sudo mv ./kubectl /usr/local/bin/kubectl

Kubectl is a go binary which allows you to execute commands on your cluster. Your cluster could be a single node VM, such as minikube, or a set of VMs on your local computer or somewhere on a host in your data center, a bare-metal cluster, or a cluster provided by any of the cloud providers - as a service - such as GCP.

Note: Due to restrictions with virtualization inside a virtual machine (nested virtualization), you cannot run minikube on cloud VMs. Minikube is a part of the Kubernetes open source project, with the single goal of getting a simple cluster up and running with just one virtual machine acting as node.

For the remainder of this workshop, we assume you have a Kubernetes cluster on google cloud. For instructions on connecting to various types of Kubernetes cluster, check this article

Authenticate to your Google k8s cluster:

To authenticate against your cluster, you will need a gmail account. Then, run:

 # cluster connection via service account

 # Install the tools
export CLOUD_SDK_REPO="cloud-sdk-$(lsb_release -c -s)"
echo "deb http://packages.cloud.google.com/apt $CLOUD_SDK_REPO main" | sudo tee -a /etc/apt/sources.list.d/google-cloud-sdk.list
curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
sudo apt-get update && sudo apt-get install google-cloud-sdk

 # Create key file on your vm - the instructor will mail you the contents
vi keyfile.json

 # authenticate with cloud
gcloud auth activate-service-account --key-file keyfile.json

 # Get the cluster credentials for kubectl
gcloud container clusters get-credentials training-cluster --zone europe-west1-b --project praqma-education

Google will do some magic under the hood, which does a few things:

  • Fetches certificates and tokens (secrets)
  • Puts them into the Kubernetes configuration file, located at /home/.kube/config

Verify configuration:

You can verify this by looking at the config file:

kubectl config view

You should see something like this:

apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: REDACTED
    server: https://1.2.3.4
  name: gke_praqma-education_europe-west1-b_dcn-cluster-35
contexts:
- context:
    cluster: gke_praqma-education_europe-west1-b_dcn-cluster-35
    user: gke_praqma-education_europe-west1-b_dcn-cluster-35
  name: gke_praqma-education_europe-west1-b_dcn-cluster-35
current-context: gke_praqma-education_europe-west1-b_dcn-cluster-35
kind: Config
preferences: {}
users:
- name: gke_praqma-education_europe-west1-b_dcn-cluster-35
  user:
    password: secret-password-ea4a2fb76dc9
    username: admin

Furthermore you should now have access to the google cloud cluster! Verify by looking at the nodes for the cluster:

kubectl get nodes

You should be able to see something similar to what is shown below:

$ kubectl get nodes
NAME                                             STATUS    ROLES     AGE       VERSION
ip-172-20-40-108.eu-central-1.compute.internal   Ready     master    1d      v1.8.0
ip-172-20-49-54.eu-central-1.compute.internal    Ready     node      1d      v1.8.0
ip-172-20-60-255.eu-central-1.compute.internal   Ready     node      1d      v1.8.0

If you add the -o wide parameters to the above command, you will also see the public IP addresses of the nodes:

$ kubectl get nodes -o wide
NAME                                            STATUS    ROLES     AGE       VERSION        EXTERNAL-IP     OS-IMAGE                             KERNEL-VERSION   CONTAINER-RUNTIME
gke-dcn-cluster-35-default-pool-dacbcf6d-3918   Ready     <none>    17h       v1.8.8-gke.0   35.205.22.139   Container-Optimized OS from Google   4.4.111+         docker://17.3.2
gke-dcn-cluster-35-default-pool-dacbcf6d-c87z   Ready     <none>    17h       v1.8.8-gke.0   35.187.90.36    Container-Optimized OS from Google   4.4.111+         docker://17.3.2

Note: On Kubernetes clusters provided by a Kubernetes service provider, you will only see worker nodes as a result of executing the above command. On other clusters, you will see both master and worker nodes.

$ kubectl get nodes -o wide
NAME                                             STATUS    ROLES     AGE     VERSION   EXTERNAL-IP     OS-IMAGE                      KERNEL-VERSION   CONTAINER-RUNTIME
ip-172-20-40-108.eu-central-1.compute.internal   Ready     master    1d      v1.8.0    1.2.3.4         Debian GNU/Linux 8 (jessie)   4.4.78-k8s       docker://1.12.6
ip-172-20-49-54.eu-central-1.compute.internal    Ready     node      1d      v1.8.0    2.3.4.5         Debian GNU/Linux 8 (jessie)   4.4.78-k8s       docker://1.12.6
ip-172-20-60-255.eu-central-1.compute.internal   Ready     node      1d      v1.8.0    5.6.7.8         Debian GNU/Linux 8 (jessie)   4.4.78-k8s       docker://1.12.6

Note: Depending on the setup for this workshop, you may not be the only tenant on the cluster; you may be sharing it with the rest of the people around you in the course! So be careful!