EPHEMERAL DEFINITION HOW TO

We then can bootstrap the cluster with the following command: kind create cluster -config cluster.yaml -image kindest/node:v1.16.3Īfter some seconds our cluster will be ready and we can go ahead and create a Pod which we will then use to attach our debugger container. You can of course also use tools like kubeadm, minikube or others.įirst of all, we need a custom kind cluster definition (cluster.yaml) to enable the needed feature gates: kind: Cluster apiVersion: /v1alpha3 kubeadmConfigPatches: - | apiVersion: /v1beta2 kind: ClusterConfiguration metadata: name: config apiServer: extraArgs: 'feature-gates': 'EphemeralContainers=true' scheduler: extraArgs: 'feature-gates': 'EphemeralContainers=true' controllerManager: extraArgs: 'feature-gates': 'EphemeralContainers=true' - | apiVersion: /v1beta2 kind: InitConfiguration metadata: name: config nodeRegistration: kubeletExtraArgs: 'feature-gates': 'EphemeralContainers=true' nodes: - role: control-plane - role: worker In this example, I will create my cluster using kind (Kubernetes in Docker) which allows me to bootstrap a cluster based on my needs in just some seconds. PodShareProcessNamespace (beta in v1.16, and therefore already enabled by default)īecause you shouldn’t use Ephemeral Containers in production yet it’s recommended to use a dedicated environment.You will need to activate the following feature gates to be able to use them:

EPHEMERAL DEFINITION HOW TO

How to use themĪs mentioned above, Ephemeral Containers is an alpha feature and is therefore disabled by default. Or course, this is still subject to change. As an example, the following command would attach to a shell in an Ephemeral Container called debugger based on alpine into the my-pod: kubectl debug -c debugger -image=alpine my-pod - bash. In the future, you will be able to debug a container with a new kubectl debug command. One of the missing features in v.16 is the client-side integration of Ephemeral Containers which would allow us to use kubectl to create and attach to them. You can find more details about the roadmap and features in this issue. The actual roadmap mentions that it’s planed to provide a feature-complete alpha with Kubernetes v1.18. It is not yet feature-complete and should therefore not be used in a production environment until its GA. How does it work?Įphemeral Containers is a pretty new feature that was introduced in Kubernetes v1.16 as an alpha feature. But you can also pick a Linux distribution like Ubuntu or just run the Busybox images which both already contain a bunch of helpful tools. You can build your own debugging image which contains special debugging binaries or just tools like curl, OpenSSL and a MongoDB client. The debugging container can be based on any image and therefore can be customized based on your needs.

They provide the foundation to attach a debugging container to your main process which then can be used to debug any kind of issues. This is where Ephemeral Containers can help. The above-described method helps to provide a secure and reliable runtime environment but also makes it very hard to debug issues when they occur. Besides this, Ephemeral Containers can also help to debug a crashed container process which wouldn’t be possible with kubectl exec either. Unlike ordinary container images, these are not based on any kind of Linux distribution and therefore do not contain any other binaries and tools which could be executed via kubectl exec for troubleshooting purposes. Building container images using the “distroless” approach (building them from scratch) is taking this to the next level by only containing the compiled application binary. By adding only the required dependencies into the image a container lowers attack vectors and provides faster startups and deployments. The advantages of containers are that they run isolated processes by providing all needed dependencies using an immutable approach.

Ephemeral definition