Alfred Sabitzer - K8s Applications mit MicroK8S auf Raspberry PI

Die im Cluster verfügbaren Bereiche sind:

Im Konkreten:

k8s.slainte.at 87.243.186.29

default.k8s.slainte.at 87.243.186.29

Aus dem Cluster selbst:

alfred@pc1:~/yaml$ k get svc --all-namespaces | grep -v ''

NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE

ingress ingress LoadBalancer 10.152.183.126 192.168.0.210 443:31287/TCP,80:31681/TCP 22h

kube-system kubernetes-dashboard LoadBalancer 10.152.183.150 192.168.0.211 443:31449/TCP 22h

longhorn-system longhorn-frontend LoadBalancer 10.152.183.199 192.168.0.212 80:31444/TCP 22h

container-registry registry LoadBalancer 10.152.183.207 192.168.0.213 5000:32000/TCP 22h

admin chrony-udp-svc LoadBalancer 10.152.183.77 192.168.0.240 123:32658/UDP 40m

admin pgadmin-svc LoadBalancer 10.152.183.201 192.168.0.241 5432:30954/TCP,80:30675/TCP,443:30676/TCP 19m

Source Repository

Inspiration:

https://microk8s.io/docs/registry-built-in

Eine Software-Registry wird benötigt, wenn man selbst entwickelte Anwendungen lokal speicher und verwenden möchte. Prinzipiell könnte man auch öffentliche Registrys nehmen, aber wir haben ja einen k8s-cluster.

alfred@pc1:~$ microk8s enable registry:size=40Gi

Addon storage is already enabled.

Enabling the private registry

Applying registry manifest

namespace/container-registry created

persistentvolumeclaim/registry-claim created

deployment.apps/registry created

service/registry created

configmap/local-registry-hosting configured

The registry is enabled

The size of the persistent volume is 40Gi

alfred@pc1:~$

Nun ist die Registry vorhanden. Das Cluster-Setup ist wie folgt:

alfred@pc1:~$ microk8s status

microk8s is running

high-availability: yes

datastore master nodes: 192.168.0.202:19001 192.168.0.203:19001 192.168.0.204:19001

datastore standby nodes: 192.168.0.201:19001 192.168.0.205:19001

addons:

enabled:

dashboard # The Kubernetes dashboard

dns # CoreDNS

ha-clusalfred@pc1:~$ microk8s status

microk8s is running

high-availability: yes

datastore master nodes: 192.168.0.202:19001 192.168.0.203:19001 192.168.0.204:19001

datastore standby nodes: 192.168.0.201:19001 192.168.0.205:19001

addons:

enabled:

dashboard # The Kubernetes dashboard

dns # CoreDNS

ha-cluster # Configure high availability on the current node

helm3 # Helm 3 - Kubernetes package manager

ingress # Ingress controller for external access

metallb # Loadbalancer for your Kubernetes cluster

metrics-server # K8s Metrics Server for API access to service metrics

prometheus # Prometheus operator for monitoring and logging

rbac # Role-Based Access Control for authorisation

registry # Private image registry exposed on localhost:5000

storage # Storage class; allocates storage from host directory

disabled:

helm # Helm 2 - the package manager for Kubernetes

host-access # Allow Pods connecting to Host services smoothly

linkerd # Linkerd is a service mesh for Kubernetes and other frameworks

portainer # Portainer UI for your Kubernetes cluster

traefik # traefik Ingress controller for external access

alfred@pc1:~$

Abbildung 7: Registry Clusterdisk

Das Volume wurde als ClusterDisk angelegt. Die Storageclass longhorn ist als default eingerichtet.

Das Skript zum Einrichten der Registry ist wie folgt:

#!/bin/bash

############################################################################################

# $Date: 2021-11-23 21:37:19 +0100 (Di, 23. Nov 2021) $

# $Revision: 1285 $

# $Author: alfred $

# $HeadURL: https://monitoring.slainte.at/svn/slainte/trunk/k8s/k8s/K13_registry.sh $

# $Id: K13_registry.sh 1285 2021-11-23 20:37:19Z alfred $

#

# Schnell-Installation microk8s - Installation praktischer AddOns

#

############################################################################################

#shopt -o -s errexit #—Terminates the shell script if a command returns an error code.

shopt -o -s xtrace #—Displays each command before it’s executed.

shopt -o -s nounset #-No Variables without definition

# Voraussetzung: Sauber installierte Nodes, Verbundener Cluster

sname=$(basename "$0")

app="mikrok8s/install/${sname}"

pf=\$"Revision: "

sf=" "\$

fr="\$Revision: 1285 $"

revision=${fr#*"$pf"}

revision=${revision%"$sf"*}

xd=(`date '+%Y-%m-%d'`)

wd="${HOME}/copy/${app}/${xd}/r${revision}"

id="/opt/cluster/${app}/${xd}/r${revision}"

rm -f -R ${wd}

mkdir -p ${wd}

#

# Zu diesem Zeitpunkt sollte es eine Default-Storage-Class geben, wo das abgelegt wird.

ansible pc1 -m shell -a 'microk8s enable registry:size=40Gi'

ansible pc -m shell -a 'microk8s status --wait-ready'

#

# Adaptieren der Services

#

cat < ${wd}/do_registry.sh

#!/bin/bash

#

# \$Date: 2021-11-23 21:37:19 +0100 (Di, 23. Nov 2021) $

# \$Revision: 1285 $

# \$Author: alfred $

# \$HeadURL: https://monitoring.slainte.at/svn/slainte/trunk/k8s/k8s/K13_registry.sh $

# \$Id: K13_registry.sh 1285 2021-11-23 20:37:19Z alfred $

#

# Ändern des Services auf Loadbalancer

#

#shopt -o -s errexit #—Terminates the shell script if a command returns an error code.

shopt -o -s xtrace #—Displays each command before it’s executed.

shopt -o -s nounset #-No Variables without definition

# registry - 192.168.0.213

microk8s kubectl -n container-registry get service registry -o yaml > ${id}/registry-svc.yaml

sed 's/NodePort/LoadBalancer/' ${id}/registry-svc.yaml > ${id}/new-registry-svc.yaml

microk8s kubectl apply -f ${id}/new-registry-svc.yaml --validate=false

EOF

#

chmod 755 ${wd}/do_registry.sh

ansible pc1 -m shell -a ${id}'/do_registry.sh ' > ${wd}'/do_registry.log'

#

cat < ${wd}/do_nodes.sh

#!/bin/bash

#

# \$Date: 2021-11-23 21:37:19 +0100 (Di, 23. Nov 2021) $

# \$Revision: 1285 $

# \$Author: alfred $

# \$HeadURL: https://monitoring.slainte.at/svn/slainte/trunk/k8s/k8s/K13_registry.sh $

# \$Id: K13_registry.sh 1285 2021-11-23 20:37:19Z alfred $

#

# Eintragen der Nodes in die hosts-Datei

#

#shopt -o -s errexit #—Terminates the shell script if a command returns an error code.

shopt -o -s xtrace #—Displays each command before it’s executed.

shopt -o -s nounset #-No Variables without definition

sudo sed --in-place '/docker.registry/d' /etc/hosts

microk8s kubectl -n container-registry get service registry -o yaml > ${id}/nodes-registry-svc.yaml

ip=\$(cat ${id}/nodes-registry-svc.yaml | grep -i " ip: " | awk '{print \$3 }')

text="\${ip} docker.registry"

sudo sed -i "$ a \${text}" /etc/hosts

#

EOF

#

chmod 755 ${wd}/do_nodes.sh

ansible pc -m shell -a ${id}'/do_nodes.sh '

#

# Und jetzt die Repository-Info

#

cat < ${wd}/do_docker.sh

#!/bin/bash

#

# \$Date: 2021-11-23 21:37:19 +0100 (Di, 23. Nov 2021) $

# \$Revision: 1285 $

# \$Author: alfred $

# \$HeadURL: https://monitoring.slainte.at/svn/slainte/trunk/k8s/k8s/K13_registry.sh $

# \$Id: K13_registry.sh 1285 2021-11-23 20:37:19Z alfred $