added mini-howto

dcache-k8s-howto.md

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+# dCache in Kubernetes
+
+1. [Requirements](#requirements)
+1. [Minikube nano-HowTo](#minikube-env)
+1. [Preparing Helm](#helm-env)
+1. [Starting dCache](#starting-dcache)
+1. [Accessing admin interface with SSH](#accessing-admin-interface)
+1. [Accessing with from client host](#accessing-with-client)
+1. [Exposing admin pages and frontend](#quick-access-to-admin-pages-and-frontend)
+
+## Requirements
+
+- Access to kubernetes cluster (or local minikube installation). All exampled blow 
+  should work with both, unless extra noted.
+- Kubernetes cli client
+- Helm cli client
+
+## Minikube env (optional)
+
+Download the latest version of minikube:
+
+```
+curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
+sudo install minikube-linux-amd64 /usr/local/bin/minikube
+```
+
+### Rootless installation with podman
+
+```
+$ minikube config set rootless true
+$ minikube start --driver=podman --container-runtime=containerd 
+```
+
+## Helm env
+
+Install helm as described in official [docs](https://helm.sh/docs/intro/install/) and
+add helm repositories:
+
+```
+$ helm repo add bitnami https://charts.bitnami.com/bitnami
+$ helm repo add dcache https://gitlab.desy.de/api/v4/projects/7648/packages/helm/test
+$ helm repo update
+```
+
+## Starting dCache
+
+To start dCache in kubernetes two steps are required:
+
+1. start required external components
+1. start dcache
+
+It's recommended to run dCache instance in a dedicated kubernetes namespace, for
+example, _dcache-test_:
+
+```
+kubectl create namespace dcache-test
+kubectl config set-context --current --namespace=dcache-test 
+```
+
+All following command commands assume that the namespace is set. Otherwise `-n other-namespace`
+flag should be passes to all `helm` and `kubeclt` commands.
+
+Then start required infrastructure (zookeeper, postgresql, kafka) 
+
+```
+$ helm install --wait --set auth.username=dcache --set auth.password=let-me-in --set auth.database=chimera  chimera bitnami/postgresql
+$ helm install --wait cells bitnami/zookeeper
+$ helm install --wait --set externalZookeeper.servers=cells-zookeeper --set kraft.enabled=false billing bitnami/kafka --version 23.0.7
+```
+
+Then start dCache
+
+```
+$ helm install --wait --set image.tag=9.2.1 store dcache/dcache
+```
+
+All running helm charts can be listed with:
+
+```
+$ helm list
+```
+
+## Accessing admin interface
+
+```
+$ kubectl run -ti --rm --image=kroniak/ssh-client admmin -- ssh -p 22224 admin@store-door-svc
+```
+
+## Accessing with client
+
+Starting a client host and attach to it.
+
+```
+$ kubectl run --image=almalinux:9 wn -- sleep inf
+$ kubectl -ti exec wn -- /bin/bash
+$ kubectl -ti exec wn -- curl -v -k -X HEAD https://store-door-svc:8083/ 
+```
+
+## Quick access to admin pages and frontend
+
+(For minikube users)
+
+```
+$ kubectl expose pod store-dcache-door-0 --type=NodePort --port=2288 --name="web-admin"
+$ kubectl expose pod store-dcache-door-0 --type=NodePort --port=3880 --name="frontend" 
+```
+
+```
+$ minikube service web-admin -n dcache-test
+```