Harness
This walkthrough shows you how to pass CloudTruth parameters to Harness with a K8s operator.
Prerequisites
You have kubectl installed.
AWS CLI configured.
You have created one or more CloudTruth Parameters.
You have created a CloudTruth API Access token.
Create Kubernetes Cluster
The first step in the process is to deploy our Kubernetes cluster on our cloud provider. For this tutorial we are going to be using Amazon EKS, which is a managed container service. It would be fairly trivial to replicate these steps using another managed container service such as Google Kubernetes Engine (GKE) or Azure Kubernetes Service (AKS). If your cluster is already deployed, you can skip to "Setting up Harness".
Amazon EKS Cluster
The easiest way to deploy an Amazon EKS cluster is using eksctl, a simple CLI tool for managing EKS clusters. The instructions for how to install or upgrade eksctl are here. However if another option is preferred, this link gives details on how to deploy via eksctl, the AWS Management Console, or the AWS CLI.
To deploy a cluster with eksctl in your default region you can execute the following:
Create Nodes for EKS Cluster
Once the EKS cluster is created, you must make sure there is a node group attached that can handle your workloads. Harness delegates require a minimum of 8Gb of memory so we are using tx.xlarge nodes.
If the basic eksctl command was used, the cluster is created by default without any node groups attached. To attach worker nodes, simply follow this link that will walk you through the following commands.
Create a key pair to allow access to the node group instances:
Create a node group with the following command:
Note: If you used a method other than eksctl to spin up your EKS cluster, make sure your local kubectl points to your cluster, which can be done by updating your kubeconfig.
Setting up Harness
Now that our cluster is up and running, it is time to set up Harness. The first step in doing so is adding a harness delegate to our cluster with the Harness First Generation Community Edition. For EKS, this is as simple as downloading the harness delegate yaml and applying it with:
kubectl apply -f harness-delegate.yaml
Let's verify that our harness delegate is running by executing the command:
kubectl --namespace harness-delegate get pods
We can also verify this in the Harness GUI under Setup > Harness Delegates (right hand side menu) and checking that our delegate shows up with a "Connected" status.
Adding Cloud Provider and Helm Repository
The next step is to add our Kubernetes cluster cloud provider to Harness. This is trivially easy to do when you inherit the authentications settings from the Harness delegate we installed in the previous step. To add a Cloud Provider, go to Setup > Cloud Providers > Add Cloud Provider > "Kubernetes Cluster".
Cluster Details: "Inherit from selected Delegate"
Delegate Selector: "eks-qqiuw-0"
We also need to add our KubeTruth Helm repository which is a K8s operator that continuously pulls CloudTruth parameters into ConfigMaps and Secrets in our Kubernetes cluster. Read more about KubeTruth here. To add the Helm repository, go to Setup > Connectors (on right hand menu) > Artifact Servers > "Add Artifact Server".
Type: Helm Repository
Name: "KubeTruthHelm"
Repository URL: "https://packages.cloudtruth.com/charts"
Adding a new Application and Service
To add a new application navigate to Setup > "Add Application", and give it whatever name you like, "KubeTruthDemo" in our case.
Once we create the application, we must add a service to it. Navigate to Services > "Add Service". Provide the service a name ("DemoService" in our case), and the deployment type must be "Kubernetes".
On the service overview page click on the 3 dots in the upper right corner of "Manifests" and select the option that says "Link Remote Manifests".
Provide the following details and submit the services remote manifest:
Manifest Format: Helm Chart from Helm Repository
Helm Repository: KubetruthHelm (that we set up earlier)
Chart Name: "kubetruth" (case sensitive)
Helm Version: v3 (or v2 if you prefer to use that)
On the service overview page, scroll down to "Values YAML Override" and click "Add Values". Choose the option "inline", here you are going to want to add the CloudTruth API key you created as a prerequisite, the YAML is as follows:
Optionally, we can also add a CloudTruth environment using the appSettings.environmentkey, but since we created our parameters in the "default" CloudTruth environment we can omit that key.
Adding an Environment
The next step is to set up an environment on Harness to do our deployment. Navigate to Setup > Our App (KubetruthDemo) > Environments > "Add Environment". Provide a name, we will call it "DemoEnv". You can either select Production or Non-Production for Environment Type, we will create a Production for the purposes of this tutorial.
Once the environment is created, we need to add an infrastructure definition for it. On the Environment Overview page click "Add Infrastructure Definition" and provide the following details.
Name: "EKSCluster"
Cloud Provider Type: Kubernetes Cluster
Deployment Type: Kubernetes
Select bubble for "Use Already Provisioned Infrastructure"
Cloud Provider: Kubernetes Cluster
Namespace is fine as "default"
Release Name: keep default
Creating Deployment Workflow
It is time to create a deployment workflow, for this navigate to Setup > Our App (Kubetruth Demo) > Workflows > "Add Workflow" and provide the following details.
Name: "RollingWorkflow"
Workflow Type: Rolling Deployment
Environment: DemoEnv (created in earlier step)
Service: DemoService (created in earlier step)
Infrastructure Definition: EKSCluster (created in earlier step)
From the Workflow Overview, we need to add a pre-deploy step to apply our KubeTruth CRD. Under the "Deploy" section click "Add Step" .
Navigate to Utility > Shell Script.
Provide the following step details:
Name: "Shell Script"
Script Type: BASH
Script:
Important: Make sure to hit the little up arrow to the direct right of "Shell Script" under the "Deploy" section, since we want it to execute before the rollout deployment.
If done as a canary or blue/green deployment, make sure the shell script is entered as a "Pre-Deployment" step, since it needs to execute before the actual deployment (or else the CRD will not exist).
Now you can hit "Deploy" on the upper right (then "Submit")!
Verifying our Deployment
To verify that our KubeTruth deployment was successful and that our demo CloudTruth parameters are in our Kubernetes cluster, we need to look at the ConfigMap and for the "default" Kubernetes namespace (or whatever namespace you deployed to).
The easiest way to do this is to navigate to your terminal and list all of your configmaps. You will see that you now have configmaps created from your CloudTruth Projects.
kubectl get configmap -A
Describe details from a specific configmap created from your workflow:
kubectl describe configmap "generated-configmap-name"
To check the value of a specific key, run:
If you want to verify the rolling updates to the ConfigMap, try changing a parameter value in CloudTruth and checking for the updated value using kubectl after a minute or two.
You have successfully deployed a Kubernetes operator that dynamically generates and updates configmaps and secrets! To clean up your AWS clusters you can run the following:
eksctl delete nodegroup NODEGROUPNAME _--_cluster __ YOUR-CLUSTER-NAME
aws ec2 delete-key-pair --key-name KEY_NAME
eksctl delete cluster YOUR-CLUSTER-NAME
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