Kubernetes in Docker - Killing Bugs with KINDness

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Killing Bugs with KINDness Introduction to Kubernetes in Docker (KIND) By Josh Michielsen Senior Software Engineer Condé Nast International (@condenasteng) 1

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About Me Senior Software Engineer Australian Cyclist Photographer Dog Lover @jmickey_ jmichielsen jmickey mickey.dev [email protected] 2

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What is KIND? kind is a tool for running local Kubernetes clusters using Docker container "nodes". - https://kind.sigs.k8s.io/ 4

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KIND Architecture 5 via https://kind.sigs.k8s.io/docs/design/initial

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Why KIND? 6 1 Rapid startup time (~30 sec) 2 Supports multi-node HA clusters 3 Supports Windows, macOS, and Linux 4 CNCF certiﬁed conformant 5 Exposes the Kubeadm conﬁg surface

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Installing KIND 1 Via Go GO111MODULE=”on” go get sigs.k8s.io/[email protected] 2 Via Docker (from source) git clone https://github.com/kubernetes-sigs/kind.git make build 3 Via Pre-Compiled Binaries Download from https://github.com/kubernetes-sigs/kind/releases Copy to $PATH 7

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8 kind create cluster

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9 Launch Specific Kubernetes Version kind create cluster --image kindest/node:v1.13.7 Additional Clusters kind create cluster --name cluster-2 Pass Config kind create cluster --config Retrieve KubeConfig & Set $KUBECONFIG kind get kubeconfig export KUBECONFIG="$(kind get kubeconfig-path)" Sideload Docker Image kind load docker-image hello-world Sideload Docker Archive kind load image-archive archive.tar.gz

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10 KIND has its own configuration API which can be used to describe the desired state of a cluster. Such as: - Nodes - Port Mappings - Networking KIND also exposes the Kubeadm configuration surface through config patch structs. Configuration

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11 HA Cluster Additional Port Mappings Use with NodePort services to allow ingress to applications.

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12 Kubeadm Patch

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13 Use Cases 1 Local Development. Caveats: No Load Balancer or ClusterIP support. Limited use case for testing ingress services. 2 CI: Helm Charts Validation Test that changes to helm charts within CI to ensure all services are deployed correctly. 3 Cluster Config Sanity check cluster config changes, e.g. Pod Affinity/Anti-Affinity. 4 Pre-merge Ephemerial Deployments Testing application changes in short-lived environments. A common use case within the Kubernetes team is testing Operators.

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KIND in CI KIND has been tested, and is working, within a number of popular CI systems, including: CircleCI, TravisCI, GitLab, Concourse, Azure Pipelines, and Drone. A repo of example conﬁgurations for various CI systems is maintained here: https://github.com/kind-ci/examples 14

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Comparison to Alternatives 15 Minikube ● Either requires a Hypervisor, or will create a container for each control plane component. ● Not CI friendly. ● Much slower to start. Docker Desktop Kubernetes ● Slow to install. ● Single node cluster, no HA support. ● Not CI friendly. ● More resource intensive.

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Additional Features 16 Mount host machine ﬁlesystem paths Customise networking Customisable listenAddress and API ports

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17 @jmickey_ jmichielsen jmickey mickey.dev [email protected] Thanks for listening!