Kubernetes - Revision history

Goldbolt at 14:23, 28 June 2024

2024-06-28T14:23:57Z

Goldbolt at 16:09, 13 June 2024

2024-06-13T16:09:34Z

Goldbolt at 20:21, 20 March 2023

2023-03-20T20:21:59Z

Goldbolt at 20:21, 20 March 2023

2023-03-20T20:21:28Z

Goldbolt at 20:19, 20 March 2023

2023-03-20T20:19:43Z

Goldbolt: /* Install Kubernetes to Ubuntu */

2023-03-16T16:42:50Z

‎Install Kubernetes to Ubuntu

Goldbolt: /* Install Kubernetes to Ubuntu */

2023-03-16T15:59:32Z

‎Install Kubernetes to Ubuntu

Goldbolt: Created page with "Kubernetes (/ˌk(j)uːbərˈnɛtɪs, -ˈneɪtɪs, -ˈneɪtiːz, -ˈnɛtiːz/, commonly abbreviated K8s) is an open-source container orchestration system for automating softwar..."

2023-03-10T21:00:34Z

Created page with "Kubernetes (/ˌk(j)uːbərˈnɛtɪs, -ˈneɪtɪs, -ˈneɪtiːz, -ˈnɛtiːz/, commonly abbreviated K8s) is an open-source container orchestration system for automating softwar..."

New page

Kubernetes (/ˌk(j)uːbərˈnɛtɪs, -ˈneɪtɪs, -ˈneɪtiːz, -ˈnɛtiːz/, commonly abbreviated K8s) is an open-source container orchestration system for automating software deployment, scaling, and management. Originally designed by Google, the project is now maintained by the Cloud Native Computing Foundation.

The name Kubernetes originates from Greek, meaning 'helmsman' or 'pilot'. Kubernetes is often abbreviated as K8s, counting the eight letters between the K and the s (a numeronym).

Kubernetes works with containerd and CRI-O. Its suitability for running and managing large cloud-native workloads has led to widespread adoption of it in the data center. There are multiple distributions of this platform – from ISVs as well as hosted-on cloud offerings from all the major public cloud vendors.

=Install Kubernetes to Ubuntu=
The following commands will install microk8s to Ubuntu:
sudo snap install microk8s --classic

Add your user to the microk8s admin group and fix permissions:
sudo usermod -a -G microk8s $USER
sudo chown -f -R $USER ~/.kube

Log out and log back in to that user for this to take effect.

Check the status of the service:
microk8s status --wait-ready

Enable services:
microk8s enable dashboard dns ingress

Use the following to check for available services to enable:
microk8s enable --help

Start using microk8s:
microk8s kubectl get all --all-namespaces

Access the dashboard:
microk8s dashboard-proxy

=Clustering=
To create a cluster out of two or more already-running MicroK8s instances, use the microk8s add-node command. As of MicroK8s 1.19, clustering of three or more nodes will automatically enable high availability. The MicroK8s instance on which the command is run will host the Kubernetes control plane:
microk8s add-node

The add-node command prints a microk8s join command which should be executed on the MicroK8s instance(s) that you wish to join to the cluster (NOT THE NODE YOU RAN add-node FROM). For example:
microk8s join ip-172-31-20-243:25000/DDOkUupkmaBezNnMheTBqFYHLWINGDbf

Joining a node to the cluster should only take a few seconds. Afterwards you should be able to see the node has joined:
microk8s kubectl get no

← Older revision		Revision as of 14:23, 28 June 2024
Line 45:		Line 45:

	kubectl delete -f persistentvolume01.yaml		kubectl delete -f persistentvolume01.yaml
		+
		+	Enter the MongoDB database shell 'mongosh':
		+	kubectl exec -it database-sw-mongo-0 -- mongosh -u $(kubectl get secret database-sw-mongo-admin -o jsonpath='{.data.user}' \| base64 -d) -p $(kubectl get secret database-sw-mongo-admin -o jsonpath='{.data.password}' \| base64 -d) --authenticationDatabase admin --tls --tlsAllowInvalidHostnames --tlsAllowInvalidCertificates database
		+
		+
		+	Set password for MongoDB user to be "somehash":
		+	db.AspNetUsers.updateOne( {"Name": "username"}, { $set: {"PasswordHash": "somehash"} } )
		+
		+
		+	Show all current attachments in selected database:
		+	db.getCollection("Records").aggregate([ { /* match all records with an attachment field value/ $match: { "Values": { $elemMatch: { "v._v": { $elemMatch: { _t: "Attachment" } } } } } }, { / project to reduce size/ $project: { "Values": 1 } }, { / unwind into individual fields/ $unwind: "$Values" }, { / match attachment fields/ $match: { "Values.v._v": { $elemMatch: { _t: "Attachment" } } } }, { / unwind into individual attachments*/ $unwind: "$Values.v._v" }] );

← Older revision		Revision as of 16:09, 13 June 2024
Line 4:		Line 4:

	Kubernetes works with containerd and CRI-O. Its suitability for running and managing large cloud-native workloads has led to widespread adoption of it in the data center. There are multiple distributions of this platform – from ISVs as well as hosted-on cloud offerings from all the major public cloud vendors.		Kubernetes works with containerd and CRI-O. Its suitability for running and managing large cloud-native workloads has led to widespread adoption of it in the data center. There are multiple distributions of this platform – from ISVs as well as hosted-on cloud offerings from all the major public cloud vendors.
		+
		+	=Show all current pods=
		+	kubectl get pods
		+
		+	=Show current persistent volumes=
		+	kubectl get pv
		+
		+	=Show current persistent volume claims=
		+	kubectl get pvc
		+
		+	=Copy a file into a container of a pod=
		+
		+	kubectl cp start.sh pod1:/tmp/ -c container1
		+
		+	=Execute a command within a container of a pod=
		+
		+	kubectl exec -it pod1 -c container1 -- /tmp/start.sh
		+
		+	=Create a persistent volume for a pod to claim=
		+	Create the yaml first.
		+	echo "---
		+	apiVersion: v1
		+	kind: PersistentVolume
		+	metadata:
		+	name: persistentvolume01
		+	spec:
		+	accessModes:
		+	- ReadWriteOnce
		+	capacity:
		+	storage: 10Gi
		+	storageClassName: manual
		+	hostPath:
		+	path: /mnt/somedir" > persistentvolume01.yaml
		+
		+	Create the actual volume using the yaml:
		+
		+	kubectl create -f persistentvolume01.yaml
		+
		+	Delete the persistent volume if necessary:
		+
		+	kubectl delete -f persistentvolume01.yaml
		+

	=Install Kubernetes to Ubuntu=		=Install Kubernetes to Ubuntu=

← Older revision		Revision as of 20:21, 20 March 2023
Line 104:		Line 104:
	== References ==		== References ==

−	* [https://microk8s.io/docs/nfs Use NFS for Persistent Volumes]	+	* [https://microk8s.io/docs/nfs Microk8s Documentation \| Use NFS for Persistent Volumes]

← Older revision		Revision as of 20:21, 20 March 2023
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	Check the PVC configuration:		Check the PVC configuration:
	microk8s kubectl describe pvc my-pvc		microk8s kubectl describe pvc my-pvc
		+
		+	== References ==
		+
		+	* [https://microk8s.io/docs/nfs Use NFS for Persistent Volumes]

← Older revision		Revision as of 20:19, 20 March 2023
Line 39:		Line 39:
	Joining a node to the cluster should only take a few seconds. Afterwards you should be able to see the node has joined:		Joining a node to the cluster should only take a few seconds. Afterwards you should be able to see the node has joined:
	microk8s kubectl get no		microk8s kubectl get no
		+
		+	=Use NFS for Persistent Volumes=
		+	Provision NFS mounts as Kubernetes Persistent Volumes on MicroK8s.
		+
		+	==NFS server==
		+	Either use a current NFS server or install a NFS server. The following is how to install to Ubuntu:
		+	apt install nfs-kernel-server
		+	Directory /srv/nfs is the share folder.
		+	mkdir -p /srv/nfs
		+	chown nobody:nogroup /srv/nfs
		+	chmod 0777 /srv/nfs
		+	Edit the /etc/exports. The following will allow all IP addresses in the 10.0.0.0/24 subnet:
		+	/srv/nfs 10.0.0.0/24(rw,sync,no_subtree_check)
		+	Restart the NFS server:
		+	systemctl restart nfs-kernel-server
		+
		+	==Install the CSI driver for NFS==
		+	Enable the Helm3 addon (if not already enabled) and add the repository for the NFS CSI driver:
		+	microk8s enable helm3
		+	microk8s helm3 repo add csi-driver-nfs https://raw.githubusercontent.com/kubernetes-csi/csi-driver-nfs/master/charts
		+	microk8s helm3 repo update
		+	This will install the Helm chart under the kube-system namespace:
		+	microk8s helm3 install csi-driver-nfs csi-driver-nfs/csi-driver-nfs --namespace kube-system --set kubeletDir=/var/snap/microk8s/common/var/lib/kubelet
		+	After deploying the Helm chart, wait for the CSI controller and node pods to come up using the following kubectl command:
		+	microk8s kubectl wait pod --selector app.kubernetes.io/name=csi-driver-nfs --for condition=ready --namespace kube-system
		+	If successful, you will see "condition met".
		+	List the available CSI drivers in the Kubernetes cluster:
		+	microk8s kubectl get csidrivers
		+	==Create a StorageClass for NFS==
		+	This creates a Kubernetes Storage Class which uses the nfs.csi.k8s.io CSI driver. Create the following file sc-nfs.yaml and change 10.0.0.42 to the NFS server:
		+
		+	apiVersion: storage.k8s.io/v1
		+	kind: StorageClass
		+	metadata:
		+	name: nfs-csi
		+	provisioner: nfs.csi.k8s.io
		+	parameters:
		+	server: 10.0.0.42
		+	share: /srv/nfs
		+	reclaimPolicy: Delete
		+	volumeBindingMode: Immediate
		+	mountOptions:
		+	- hard
		+	- nfsvers=4.1
		+	Apply it on the MicroK8s cluster:
		+	microk8s kubectl apply -f - < sc-nfs.yaml
		+
		+	The final step is to create a new 5gb PersistentVolumeClaim using the nfs-csi storage class. This is as simple as specifying storageClassName as nfs-csi in the PVC definition within the file pvc-nfs.yaml:
		+	apiVersion: v1
		+	kind: PersistentVolumeClaim
		+	metadata:
		+	name: my-pvc
		+	spec:
		+	storageClassName: nfs-csi
		+	accessModes: [ReadWriteOnce]
		+	resources:
		+	requests:
		+	storage: 5Gi
		+	Then create the PVC with:
		+	microk8s kubectl apply -f - < pvc-nfs.yaml
		+	Check the PVC configuration:
		+	microk8s kubectl describe pvc my-pvc

@@ Line 19: / Line 19: @@
 Enable services:
-     microk8s enable dashboard dns ingress metallb metrics-server observability
+     microk8s enable dashboard dns ingress metallb
 Use the following to check for available services to enable: