K8s: Difference between revisions

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==K8s Lens==
<syntaxhighlight lang="bash">
# install from snapcraft
sudo snap install kontena-lens --classic
# license version
curl -fsSL https://downloads.k8slens.dev/keys/gpg\
| sudo gpg --dearmor -o /etc/apt/keyrings/k8slens.gpg
cat << EOF | sudo tee /etc/apt/sources.list.d/k8slens.list >/dev/null
deb [arch=$(dpkg --print-architecture)\
signed-by=/etc/apt/keyrings/k8slens.gpg]\
https://downloads.k8slens.dev/apt/debian stable main
EOF
sudo apt install lens
lens-desktop
</syntaxhighlight>
==Kind==
==Kind==
{|
{|
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{|
{|
|valign='top'|
|valign='top'|
<source lang="properties">
<syntaxhighlight lang="properties">
cat <<EOF | kubectl apply -f -
cat <<EOF | kubectl apply -f -
apiVersion: v1
apiVersion: v1
Line 67: Line 86:
   storageClassName: chorke-local-storage
   storageClassName: chorke-local-storage
EOF
EOF
</source>
</syntaxhighlight>


|valign='top'|
|valign='top'|
<source lang="properties">
<syntaxhighlight lang="properties">
cat <<EOF | kubectl delete -f -
cat <<EOF | kubectl delete -f -
apiVersion: v1
apiVersion: v1
Line 107: Line 126:
   storageClassName: chorke-local-storage
   storageClassName: chorke-local-storage
EOF
EOF
</source>
</syntaxhighlight>


|-
|-
Line 126: Line 145:


|}
|}
==Storage==
# Ceph RBD
# GlusterFS
# OpenEBS
# Longhorn
# Rook


==Argo CD==
==Argo CD==
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  kubectl get pods -A -o jsonpath='{range .items[*]}{"\n"}{.metadata.name}{":\t"}{range .spec.containers[*]}{.image}{", "}{end}{end}' |sort
  kubectl get pods -A -o jsonpath='{range .items[*]}{"\n"}{.metadata.name}{":\t"}{range .spec.containers[*]}{.image}{", "}{end}{end}' |sort
  kubectl get pods -A -o jsonpath="{.items[*].spec.containers[*].image}" |tr -s '[[:space:]]' '\n' |sort |uniq -c
  kubectl get pods -A -o jsonpath="{.items[*].spec.containers[*].image}" |tr -s '[[:space:]]' '\n' |sort |uniq -c
kubectl delete pod academia-<hash> -n chorke --force --grace-period=0
kubectl delete pod academia-<hash> -n chorke
kubectl get pod academia-<hash> -n chorke -o yaml
kubectl describe pod academia-<hash> -n chorke
kubectl edit pod academia-<hash> -n chorke
kubectl get pod academia-<hash> -n chorke
kubectl logs academia-<hash> -n chorke
kubectl get events -n chorke


==Knowledge==
==Knowledge==
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|valign="top"|
|valign="top"|
<source lang='bash'>
<syntaxhighlight lang='bash'>
minikube addons enable default-storageclass
minikube addons enable default-storageclass
minikube addons enable metrics-server
minikube addons enable metrics-server
minikube addons enable metallb
minikube addons enable metallb
</source>
</syntaxhighlight>


|valign="top"|
|valign="top"|
<source lang='bash'>
<syntaxhighlight lang='bash'>
minikube addons configure metallb
minikube addons configure metallb
minikube addons enable olm
minikube addons enable olm
minikube addons list
minikube addons list
</source>
</syntaxhighlight>


|-
|-
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|-
|-
| valign="top" |
| valign="top" |
  kubectl exec -it <pod_name-hash> -- bash
  kubectl exec -it <pod-nmae-hash> -- bash
  kubectl exec -it <pod_name-hash> -n chorke -- bash
  kubectl exec -it <pod-name-hash> -n <ns> -- bash
  kubectl exec -it <pod-name-hash> -n <ns> -- printenv
 
| valign="top" |
kubectl logs <pod-nmae-hash>
kubectl logs <pod-nmae-hash> -n <ns>
kubectl logs <pod-nmae-hash> -n <ns> -p


| valign="top" |
| valign="top" |
  minikube addons enable ingress
  minikube addons enable ingress
kubectl get pods -n ingress-nginx
kubectl logs <pod-nmae-hash> -c <image-name> -n <ns>
|-
|colspan="3"|
----
|-
| valign="top" |
minikube addons enable ingress-dns
nslookup academia.local $(minikube ip)
kubectl get configmap coredns -n kube-system -o yaml
| valign="top" |


| valign="top" |
| valign="top" |
kubectl get pods -n ingress-nginx


|}
|}
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{|
{|
| valign="top" |
| valign="top" |
* [https://foxutech.medium.com/kubernetes-crashloopbackoff-how-to-troubleshoot-940dbb16bc84 K8s » CrashLoopBackOff » Medium]
* [https://devopscube.com/setup-kubernetes-cluster-kubeadm/ K8s » Kubeadm » Setup Cluster]
* [https://docs.openshift.com/container-platform/4.9/applications/deployments/what-deployments-are.html K8s » What Deployments Are]
* [https://docs.openshift.com/container-platform/4.9/applications/deployments/what-deployments-are.html K8s » What Deployments Are]
* [https://kubernetes.io/docs/concepts/storage/ephemeral-volumes/ K8s » Volumes » Ephemeral]
* [https://kubernetes.io/docs/concepts/storage/ephemeral-volumes/ K8s » Volumes » Ephemeral]
Line 227: Line 283:


| valign="top" |
| valign="top" |
* [https://www.groundcover.com/blog/crashloopbackoff K8s » CrashLoopBackOff » GroundCover]
* [https://spacelift.io/blog/crashloopbackoff K8s » CrashLoopBackOff » Spacelift]
* [https://www.blinkops.com/blog/troubleshooting-the-crashloopbackoff-error K8s » CrashLoopBackOff » Blinkops]
* [https://kubernetes.io/docs/tasks/administer-cluster/dns-custom-nameservers/ K8s » DNS Service » Customizing]
* [https://medium.com/kubernetes-tutorials/kubernetes-dns-for-services-and-pods-664804211501 K8s » DNS for Services and Pods]
* [https://stackoverflow.com/questions/50952240/ K8s » Connect to Host Database]
* [https://minikube.sigs.k8s.io/docs/handbook/addons/ingress-dns/ K8s » Minikube » Ingress DNS]
* [https://www.keycloak.org/server/hostname K8s » Keycloak » Hostname]
* [https://medium.com/@pczarkowski/kubernetes-tip-run-an-interactive-pod-d701766a12 K8s » Interactive Pod]
* [https://spacelift.io/blog/restart-kubernetes-pods-with-kubectl K8s » Restart Pods]
| valign="top" |
* [https://microk8s.io/compare K8s » MicroK8s vs K3s vs Minikube]
* [https://georgepaw.medium.com/how-to-run-the-cheapest-kubernetes-cluster-at-1-per-day-9287abb90cee K8s » Cheapest Cluster $1/Day]
* [https://cert-manager.io/docs/ K8s » Ingress » Cert Manager]
* [https://docs.k8slens.dev/getting-started/install-lens/ K8s » Lens » Getting Started]
* [https://getbetterdevops.io/k8s-ingress-with-letsencrypt/ K8s » Ingress » Letsencrypt]
* [https://github.com/MuhammedKalkan/OpenLens/releases K8s » OpenLens]
* [https://microk8s.io/docs/getting-started  K8s » MicroK8s]
* [https://www.rancher.com/quick-start K8s » Rancher]
* [https://min.io/docs/minio/kubernetes/upstream/index.html K8s » MinIO]
* [https://github.com/lensapp/lens K8s » Lens]
|-
| colspan="3" |
----
|-
| valign="top" |
* [https://itnext.io/deciphering-the-kubernetes-networking-maze-navigating-load-balance-bgp-ipvs-and-beyond-7123ef428572 K8s » Deciphering the Networking Maze]
* [https://www.hostafrica.com/blog/new-technologies/install-kubernetes-cluster-windows-server-worker-nodes/ K8s » Windows Server Worker Nodes]
* [https://aws.amazon.com/blogs/aws/introducing-karpenter-an-open-source-high-performance-kubernetes-cluster-autoscaler/ K8s » Introducing Karpenter]
* [https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands K8s » Kubectl Command]
* [https://kubernetes.io/docs/reference/kubectl/#resource-types K8s » Resource types]
* [https://kubernetes.io/docs/reference/setup-tools/kubeadm/ K8s » Kubeadm]
* [https://kubernetes.io/docs/reference/kubectl/ K8s » Kubeactl]
* [https://kubernetes.io/docs/reference/networking/virtual-ips/ K8s » IPVS]
* [https://kubernetes.io/docs/concepts/extend-kubernetes/compute-storage-net/network-plugins/ K8s » CNI]
| valign="top" |
* [[K8s/CSI Hostpath Driver|K8s » CSI Hostpath Driver]]


| valign="top" |
| valign="top" |

Latest revision as of 09:01, 1 August 2024

K8s Lens

# install from snapcraft
sudo snap install kontena-lens --classic

# license version
curl -fsSL https://downloads.k8slens.dev/keys/gpg\
| sudo gpg --dearmor -o /etc/apt/keyrings/k8slens.gpg

cat << EOF | sudo tee /etc/apt/sources.list.d/k8slens.list >/dev/null
deb [arch=$(dpkg --print-architecture)\
 signed-by=/etc/apt/keyrings/k8slens.gpg]\
 https://downloads.k8slens.dev/apt/debian stable main
EOF

sudo apt install lens
lens-desktop

Kind

  • Pod
  • PersistentVolume
  • PersistentVolumeClaim
  • Deployment
  • DeploymentConfig
  • ReplicaSet
  • ReplicationController
  • StorageClass

Volume

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: PersistentVolume
metadata:
  name: chorke-pv
spec:
  capacity:
    storage: 10Gi
  volumeMode: Filesystem
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: chorke-local-storage
  hostPath:
    path: /home/shahed/.chorke/academia/var/k8s
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: k8s.io/minikube-hostpath
          operator: In
          values:
          - node-hostname   
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: chorke-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
  storageClassName: chorke-local-storage
EOF
cat <<EOF | kubectl delete -f -
apiVersion: v1
kind: PersistentVolume
metadata:
  name: chorke-pv
spec:
  capacity:
    storage: 10Gi
  volumeMode: Filesystem
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: chorke-local-storage
  hostPath:
    path: /home/shahed/.chorke/academia/var/k8s
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: k8s.io/minikube-hostpath
          operator: In
          values:
          - node-hostname   
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: chorke-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
  storageClassName: chorke-local-storage
EOF


Storage

  1. Ceph RBD
  2. GlusterFS
  3. OpenEBS
  4. Longhorn
  5. Rook

Argo CD

kubectl create namespace argocd
kubectl get namespace -A

kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

kubectl get -n=argocd pod
kubectl get -n=argocd service -n argocd
kubectl port-forward -n=argocd service/argocd-server 8080:80

kubectl get -n=argocd -o=yaml secret argocd-initial-admin-secret
echo  RE83Uk81QTU5clZyLTlsdg== | base64 --decode
https://localhost:8080/login

kubectl get -n=argocd configmap
kubectl get -n=argocd deployment
kubectl get -n=argocd service
kubectl get -n=argocd secret
kubectl get -n=argocd event
kubectl get -n=argocd pod
kubectl edit -n=argocd configmap  argocd-rbac-cm
kubectl edit -n=argocd configmap  argocd-cm
kubectl edit -n=argocd deployment argocd-redis
kubectl edit -n=argocd service    argocd-redis
kubectl edit -n=argocd secret     argocd-secret
kubectl edit -n=argocd pod        argocd-app-ctrl-0
kubectl get -n=argocd -o=yaml configmap  argocd-rbac-cm
kubectl get -n=argocd -o=yaml configmap  argocd-cm
kubectl get -n=argocd -o=yaml deployment argocd-redis
kubectl get -n=argocd -o=yaml service    argocd-redis
kubectl get -n=argocd -o=yaml secret     argocd-secret
kubectl get -n=argocd -o=yaml pod        argocd-app-ctrl-0

Docker Config

kubectl create secret -n chorke generic image-pull-secret --from-file=.dockerconfigjson=${HOME}/.docker/config.json --type=kubernetes.io/dockerconfigjson
kubectl get    secret -n chorke image-pull-secret -o "jsonpath={.data.\.dockerconfigjson}" | base64 --decode
kubectl get    secret -n chorke image-pull-secret -o yaml
kubectl delete secret -n chorke image-pull-secret
kubectl get pods -A -o jsonpath='{range .items[*]}{"\n"}{.metadata.name}{":\t"}{range .spec.containers[*]}{.image}{", "}{end}{end}' |sort
kubectl get pods -A -o jsonpath="{.items[*].spec.containers[*].image}" |tr -s 'space:' '\n' |sort |uniq -c
kubectl delete pod academia-<hash> -n chorke --force --grace-period=0
kubectl delete pod academia-<hash> -n chorke
kubectl get pod academia-<hash> -n chorke -o yaml
kubectl describe pod academia-<hash> -n chorke
kubectl edit pod academia-<hash> -n chorke
kubectl get pod academia-<hash> -n chorke
kubectl logs academia-<hash> -n chorke
kubectl get events -n chorke

Knowledge

snap services maas
snap services juju
snap services lxd
minikube addons enable default-storageclass
minikube addons enable metrics-server
minikube addons enable metallb
minikube addons configure metallb
minikube addons enable olm
minikube addons list

kubectl exec -it <pod-nmae-hash> -- bash
kubectl exec -it <pod-name-hash> -n <ns> -- bash
kubectl exec -it <pod-name-hash> -n <ns> -- printenv
kubectl logs <pod-nmae-hash>
kubectl logs <pod-nmae-hash> -n <ns>
kubectl logs <pod-nmae-hash> -n <ns> -p
minikube addons enable ingress
kubectl get pods -n ingress-nginx
kubectl logs <pod-nmae-hash> -c <image-name> -n <ns>

minikube addons enable ingress-dns
nslookup academia.local $(minikube ip)
kubectl get configmap coredns -n kube-system -o yaml

References