Schlagwort: docker

Kategorien
k8s

All my k8s clusters

Its piling up… the choices do to test k8s on my mac:

  • minikube (never liked it in the past)
  • kubernetes from Docker Desktop
  • microk8s
  • kind
  • OpenShift Local (crc)

Here are some notes about how to install, pros + cons.

minikube

needs Docker Desktop, minikube container will show up. Can handle PV/PVC. (helm example: https://phoenixnap.com/kb/postgresql-kubernetes)

brew install minikube
minikube start # kubernetes v1.26.1
# cd Software/Helm/Postgres
helm install psql-test bitnami/postgresql –set persistence.existingClaim=postgresql-pv-claim –set volumePermissions.enabled=true
…
kubectl port-forward –namespace default svc/psql-test-postgresql 5432:5432 &
PGPASSWORD=“$POSTGRES_PASSWORD“ psql –host 127.0.0.1 -U postgres -d postgres -p 5432
…
chrisp:Postgres sandorm$ export POSTGRES_PASSWORD=$(kubectl get secret –namespace default psql-test-postgresql -o jsonpath=“{.data.postgres-password}“ | base64 -d)

minikube stop

Problems on my 8GB airbook, not starting up properly.

kind

kind or kubernetes in docker is a suite of tooling for local Kubernetes “clusters” where each “node” is a Docker container (kind-*) So, it needs Docker Desktop.

# start Docker Desktop
brew install kind
# create multinode cluster – downloads more
kind create cluster –config ./kind-sample.config
✓ Ensuring node image (kindest/node:v1.20.2) 🖼
…
kind get clusters
kubectl cluster-info –context kind-kind
k get nodes # must be ‚ready‘
# stop kind cluster:
docker ps -a
docker pause
# logs
kind export logs ./mylogs

Problems: node not ready. PVC: see https://stackoverflow.com/questions/62694361/how-to-reference-a-local-volume-in-kind-kubernetes-in-docker

 k describe nodes | grep 'not ready'
  Ready            False   Tue, 07 Mar 2023 14:11:34 +0100   Tue, 07 Mar 2023 14:11:17 +0100   KubeletNotReady              runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:Network plugin returns error: cni plugin not initialized

No problems on a fresh install on my airbook:

kind create cluster –name kind-playground –config ./multinode.yaml
Creating cluster „kind-playground“ …
⠎⠁ Ensuring node image (kindest/node:v1.25.3) 🖼
⠈⠁ Ensuring node image (kindest/node:v1.25.3) 🖼
⠈⠁ Ensuring node image (kindest/node:v1.25.3) 🖼 ^C
luftichris:Kind christianhofig$ kind create cluster –name kind-playground –config ./multinode.yaml
Creating cluster „kind-playground“ …
✓ Ensuring node image (kindest/node:v1.25.3) 🖼
✓ Preparing nodes 📦 📦 📦
✓ Writing configuration 📜
✓ Starting control-plane 🕹️
✓ Installing CNI 🔌
✓ Installing StorageClass 💾
✓ Joining worker nodes 🚜
Set kubectl context to „kind-kind-playground“
You can now use your cluster with:
kubectl cluster-info –context kind-kind-playground
k cluster-info –context kind-kind-playground
Kubernetes control plane is running at https://127.0.0.1:55156
CoreDNS is running at https://127.0.0.1:55156/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use ‚kubectl cluster-info dump‘.
luftichris:Kind christianhofig$ k get nodes
NAME STATUS ROLES AGE VERSION
kind-playground-control-plane Ready control-plane 86m v1.25.3
kind-playground-worker Ready 85m v1.25.3
kind-playground-worker2 Ready 85m v1.25.3

luftichris:kubernetes_patterns christianhofig$docker exec -it 4ba648f10d3e  /bin/sh
# ps auxw
USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root           1  0.0  0.2  18756  9280 ?        Ss   09:14   0:02 /sbin/init
root          89  0.0  0.1  23152  6852 ?        S<s  09:14   0:01 /lib/systemd/systemd-journald
root         102  1.7  0.9 1866320 38280 ?       Ssl  09:15   3:22 /usr/local/bin/containerd
root         209  3.8  1.3 1882200 55400 ?       Ssl  09:17   7:30 /usr/bin/kubelet --bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/e
root         289  0.0  0.2 712228  8960 ?        Sl   09:17   0:10 /usr/local/bin/containerd-shim-runc-v2 -namespace k8s.io -id d4400a7f094891eb47c97f03ad1e25337
65535        309  0.0  0.0    996     4 ?        Ss   09:17   0:00 /pause
root         321  0.0  0.1 712484  7440 ?        Sl   09:17   0:09 /usr/local/bin/containerd-shim-runc-v2 -namespace k8s.io -id 5c59abc08ed822feec1970a1a41b017fe
65535        350  0.0  0.0    996     4 ?        Ss   09:17   0:00 /pause
root         399  0.1  0.5 753708 20700 ?        Ssl  09:17   0:12 /usr/local/bin/kube-proxy --config=/var/lib/kube-proxy/config.conf --hostname-override=kind-pl
root        2177  0.0  0.2 712228  9280 ?        Sl   11:25   0:02 /usr/local/bin/containerd-shim-runc-v2 -namespace k8s.io -id 8aa102c08b58c4633b51230426b6e8b65
65535       2198  0.0  0.0    996     4 ?        Ss   11:25   0:00 /pause
root        2441  0.0  0.4 722376 17716 ?        Ssl  11:42   0:01 registry serve /etc/docker/registry/config.yml
root        3021  0.1  0.5 731752 22704 ?        Ssl  12:16   0:01 /bin/kindnetd
root        3325  1.5  0.0   2888   928 pts/2    Ss   12:32   0:00 /bin/sh
root        3333  0.0  0.0   7060  1564 pts/2    R+   12:32   0:00 ps auxwCode-Sprache: HTML, XML (xml)

kubernetes in Docker

Enable kubernetes in Docker Desktop options.

k config set-context docker-desktop
k config view
…
– cluster:
certificate-authority-data: DATA+OMITTED
server: https://kubernetes.docker.internal:6443
name: docker-desktop
…
– context:
cluster: docker-desktop
user: docker-desktop
name: docker-desktop
…
users:
– name: docker-desktop
user:
client-certificate-data: REDACTED
client-key-data: REDACTED
..
# copy this setting to ~/.kube/docker-desktop
export KUBECONFIG=~/.kube/docker-desktop