Installing and using Calico on Oracle Container Engine (OKE)

Introduction

There are many cluster networking options for Kubernetes. Two of the most popular are: Flannel and Calico.

Flannel is a simple and easy way to configure a layer 3 network fabric designed for Kubernetes. It is also used by default by Oracle Container Services for use with Kubernetes (aka Kubernetes on Oracle Linux) and by Oracle Container Engine (OKE).

Calico provides both a layer 3 networking and a network policy engine. Its policy engine can also be used together with Flannel.

What we’ll cover

This tutorial will focus on Calico. In this tutorial, you’ll install Calico for network pod policy on your OKE Cluster. You will then test your new installation.

For additional information, see:

Before You Begin

To successfully complete this tutorial, you must have the following:

Requirements

Installing Calico

There are two routes available to you depending on how you’ve created your OKE cluster. If you’ve used Terraform in the past, you can follow the section on installing with Terraform below. Or, if you’ve previously used the cli or the Oracle Cloud Infrastructure (OCI) console, you can continue with the section on manual installation.

Installing Calico when provisioning with Terraform

If you’re provisioning your cluster with the terraform-oci-oke module, there is an option to automate its installation.

The Calico installation script in terraform-oci-oke also handles the cases when you have more than 50 nodes in your cluster and and the number of replicas needed are calculated and scaled to accordingly.

To install Calico using Terraform:

  1. Set the following variables in your terraform.tfvars file:

    create_bastion = "true"
    install_calico = "true"
    
  2. Run terraform apply:

    terraform apply -auto-approve
    

Calico is now installed. Next, test your Calico installation.

Manually installing Calico

If you’ve manually created the OKE Cluster using the cli or the Oracle Cloud Infrastructure (OCI) console, you can use the following procedure:

  1. Obtain the kubeconfig file.

  2. Set up your KUBECONFIG environment variable:

    export KUBECONFIG=/path/to/kubeconfig
    
  3. Download the Calico policy-only manifest for the Kubernetes API datastore:

    curl \
    https://docs.projectcalico.org/v3.6/getting-started/kubernetes/installation/hosted/kubernetes-datastore/policy-only/1.7/calico.yaml \
    -O
    
  4. Set a POD_CID environment varible. By default, the pod CIDR block on OKE is 10.244.0.0/16. To set this as an environment variable, use:

    export POD_CID="10.244.0.0/16"
    
  5. Replace the default pod CIDR block value (192.168.0.0/16) in the calico.yaml file.
    You can skip this step if your pod CIDR block is already set to 192.168.0.0/16.

    sed -i -e "s?192.168.0.0/16?$POD_CIDR?g" calico.yaml
    
  6. [ OKE cluster with more than 50 worker nodes only ] If your cluster consists of more than 50 worker nodes, then you need to do one additional step:

    sed -i -e 's/typha_service_name:\s"none"/typha_service_name: calico-typha/g' calico.yaml
    
  7. Apply the manifest:

    kubectl apply -f calico.yaml
    
  8. [ Recommended ] Calico also recommends a minimum of 3 replicas in production environment and 1 replica per every 200 nodes:

    kubectl -n kube-system scale --current-replicas=1 --replicas=3 deployment/calico-typha
    

    The installation steps and other recommendations can be viewed on the Calico website.

Testing Calico

If you want to dive right in and test Calico as a network pod policy engine, there are some excellent recipes ready and available for you. You should be able to take any of these for a spin.

Alternatively, if you’d prefer a more directed approach, you can always try the security tutorials on the Calico website.

What’s next

Congratulations! You’ve successfully installed Calico on your OKE Cluster.

To explore more information about development with Oracle products: