Kyma Hands-On - Part 1

former_member560697 · ‎2020 Jun 22

In the recent SAP platform discussions, Kyma has become a ?hot topic. Mainly, the announcement that Kyma will be available as a managed service from SAP seemed to gotten everyone's attention. It certainly caught my attention.

If you haven't heard of Kyma yet, there is a great blog post available that explains what Kyma is in detail. If you're looking for a short version, Kyma is an open source project part of CNCF Cloud Native Landspace that runs on top of Kubernetes to simplify the extension and integration of monolithic software.

At least, that's what I have heard.

I have yet to understand what Kyma is or does on my own. Therefore, I'm going to roll up my sleeves and experience Kyma firsthand.

If you have been curious about Kyma and looking to dig deeper into the core components, I want to encourage you to try out Kyma with me. I will be sharing my experiences in a series of blog posts which will contain a list of the steps I took, the lessons I learned, and the tips I gathered in hopes that it will amplify not only your understanding but mine as well.

Installation

To get started with Kyma, we must first install Kyma onto a cluster. Before jumping in, let me share my setup.

Mac OS Catalina version 10.15.4

Minikube version v1.11.0

Hyperkit version v0.20200224-27-g79c6a4

Kyma CLI version v1.13.0

Note: I highly recommend using a non-work device especially if it's heavily locked down by your IT department.

With the setup I shared, installing Kyma locally using Minikube can be done with just two commands.

$ kyma provision minkube

$ kyma install

Successful installation output will result in a list of all components installed, a URL for the console, username/password to access the console, and "Installation successful! Happy Kyma-ing! :)" message.

?Lessons Learned

What does installation tell us?

1. Kyma downloads A LOT of components. A list of components installed can be seen by the log output and felt by the time it takes. Installing Kyma on Minikube took ~17mins for me, so patience seems to be essential.

2. There are two versions of Kyma that's available to install: full (Kyma) and lite (Kyma Lite). The lite version is used for local development and does not install components like logging, monitoring, and etc. A full list of all components installed for full and lite version can be found here.

3. Kyma allows you the flexibility to customize the installation. By modifying a yaml file used to install components, you can enable or disable them. According to the documentation, it seems there are some components that you can not disable without providing a replacement. However, I was not able to find which components are required and which components are optional.

4. Kyma provides a console for easy visibility into the cluster and to trigger administrative actions to change the state of the cluster.

?Tips

Be patient with the installation

The installation documentation recommends Minikube version 1.6.2, but I was able to run the installation successfully with version v1.11.0 (So far, I haven't ran into any issues yet)

If installation using kyma CLI does not work, try running the installation from source code
- kyma install --source local --src-path {YOUR_KYMA_SOURCE_PATH}

Username and Password for accessing the console
- username is admin@kyma.cx
- password can be retrieved by running the following command
  - kubectl get secret admin-user -n kyma-system -o jsonpath="{.data.password}" | base64 --decode

Deploy a Sample Application

The first example available to test out Kyma functionality is a tutorial on deploying a sample service. This tutorial goes through the steps of creating a Deployment, Service, and a custom resource APIRule to deploy and expose the service’s API either insecurely or securely.

Even though the tutorial ends after securing the service’s API without details on how to access the API afterward, there is a longer version of the tutorial available if you want to explore how to retrieve tokens necessary to test the secured API.

Using both tutorials, I was able to test out the following cases

Expose a sample application without authentication

Expose a sample application with authentication using JSON Web Tokens

Expose a sample application with authentication using OAuth2

A high-level overview of the steps I took are listed below

Create a Deployment

Create a Service

Create an APIRule

Add the IP address of Minikube to a local host file

Make a call to the service without a header

Modify existing APIRule to add jwt rule

Grab a jwt token from kubeconfig

Make a call to the service with a jwt token in the header

Modify existing APIRule to add OAuth2 rule

Create an OAuth2Client

Create a Secret for OAuth2

Make a call to retrieve a token

Make a call to the service with an OAuth2 token in the header

?Lessons Learned

What does deploying a sample application tell us?

1. Kyma offers its own gateway to expose applications outside of the cluster. Kyma requires the creation of a CustomResourceDefinition apirules.gateway.kyma-project.io which is used to create Istio Virtual Service that specifies traffic routing rules to apply to a Kubernetes service.

2. Kyma's API Gateway Controller which manages apirules.gateway.kyma-project.io also allows you to secure the exposed service using Dex (JWT) and Hydra (OAuth2 Token). Enabling the two options requires interaction with ORY Oathkeeper component and is triggered to create a Rule (rules.oathkeeper.ory.sh) resource when APIRule (apirules.gateway.kyma-project.io) declares an authentication method.

3. Kyma comes with a self-signed certificate using xip.io to allow a 30-days SSL certificate for local development. A certificate can be found in a secret called apiserver-proxy-tls-cert and steps to update TLS certificate is available on their official docs.

4. Kyma automatically injects Istio envoy sidecar proxy to all pods in all namespaces except istio-system and kube-system. If needed, sidecar proxy injection can be disabled by modifying the istio-injection label to disabled. Additionally, mutual TLS (mTLS) is enabled cluster-wide with strict configuration which allows only mTLS traffic within the workloads.

?Tips

"Update your service's API to secure it" part of the tutorial returns 404 when trying to apply the yaml file.
- GitHub issue is open to address the bug
  - Example file used in tutorial does not exist

When fetching jwt token via UI, downloading kubeconfig is not possible in chrome. Try out other browsers instead (Confirmed it works with safari)
- GitHub issue(s) are open to address the bug
  - Download of kubeconfig not possible in chrome
  - Gardener unable to download kubeconfig file,CORS Issue
- It might be possible to grab it programmatically, not sure if this is possible.

Run kubectl get apirule --all-namespaces to see an existing example of APIRule resource

Using env variable in the header for jwt and OAuth2 Authentication may not work. In that case, try inserting the values instead.
- Example with env variable
  - curl -ik https://$hostname.$domain/orders -H 'Authorization: Bearer $oauth2-token'
- Example without env variable
  - curl -ik https://$hostname.$domain/orders -H 'Authorization: Bearer askadjlnckinkfnkidkmowomf'

Local domain for Minikube installation is kyma.local

Always add the IP address of Minikube to the host file on your local machine for your any services you want to expose
- echo "$(minikube ip) $hostname.kyma.local" | sudo tee -a /etc/hosts

To list OAuth2Client resource run the following command
- kubectl get oauth2client.hydra.ory.sh

--

So far, I see that Kyma offers a set of cloud-native components out of the box and removes the complexity of integrating these technologies.

This may be favorable for a lot of Kubernetes users who want production-grade services. By deferring the decision and implementation to Kyma, you can choose to focus on functionalities instead. However, this doesn't mean you get to look the other way when there's a problem with one of the components. While Kyma takes care of installation and integration, it will still be your responsibility to understand how it all fits together.

I realize that I am just scratching the surface here. This will be an iterative process for me. As I explore more, my perspective on what Kyma is and does will evolve.

I hope you came to similar conclusions as I have. If you have any feedback on my insights or want to share your own insights, I would love to hear from you!

See you in the next post! ?