Kubernetes - Revision history

Leo at 22:19, 14 June 2020

2020-06-14T22:19:01Z

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	{{Navbox Linux}}[[Category:Linux]]		{{Navbox Linux}}[[Category:Linux]]
	[[Category:~~Docker~~]]		[[Category:Containers]]
	[[Category:~~Todo~~]]		[[Category:LinuxUtilities]]

Leo: Delete /* Questions */

2019-09-10T16:35:04Z

Delete Questions

← Older revision		Revision as of 16:35, 10 September 2019
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	protocol: TCP		protocol: TCP
	}}		}}

	~~== Questions ==~~
	* What is involved in setting up a cluster on multiple VMs?
	* What is the Kubernetes API?
	* What is this persistent storage (etcd)?
	* What is the WeaveWorks network and how does it work?

	== See Also ==		== See Also ==

Leo: /* Concepts */

2019-09-10T16:33:12Z

Concepts

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	See the Kubernetes documentation at https://kubernetes.io/docs/concepts/		See the Kubernetes documentation at https://kubernetes.io/docs/concepts/

	~~In summary~~:		; Deployment
	* A ~~'''~~Deployment~~'''~~ defines the desired state for pods and ReplicaSets.		: A Deployment defines the desired state for pods and ReplicaSets.
	* A '''~~ReplicaSets~~''' creates or destroys pods depending on scaling and the number of pods that are running.		; Pod
	* A ~~'''Pod'''~~ is a ~~collection~~ of ~~container(s) all residing on one node~~.		: A Pod is a collection of container(s) all residing on one node.
	* A ~~'''~~Service~~'''~~ is an abstraction that defines the logical set of Pods. ~~The Pods could be turned off~~ or ~~migrated without affecting~~ the ~~overall Service~~.		; ReplicaSet
	* A '''Kubernetes Master~~'''~~ is responsible for maintaining the state of the Kubernetes cluster.		: A '''ReplicaSet''' creates or destroys pods depending on scaling and the number of pods that are running. Actions are managed by a ReplicationController
	* A '''Kubernetes (Worker~~) Node'''~~ is responsible for running the actual applications managed by Kubernetes.		; ReplicationController
			: A Replication controller ensure that a specific number of pod replicas are running at any one time. It is a type of Controller.
			; Controller
			: A reconciliation loop that ensures the desired state matches the actual cluster state
			; Service
			: A Service is an abstraction that defines the logical set of Pods. Think of it as a load balancer with a DNS name. As pods are added or removed, the service will update accordingly.
			; Ingress
			: An Ingress defines routes for HTTP requests comining in to the Kubernetes Ingress Controller. Specify a host and URI and its destination service.
			; Labels
			: Labels are key/value pairs that Kubernetes attaches to any objects, such as pods, Replication Controllers, Endpoints, and so on.
			; Annotations
			: Annotations are key/value pairs used to store arbitrary non-queryable metadata.
			; Secrets
			: Secrets hold sensitive information such as passwords, TLS certificates, OAuth tokens, and ssh keys.
			; ConfigMap
			: ConfigMaps are mechanisms used to inject containers with configuration data while keeping containers agnostic of Kubernetes.
			; Kubernetes Master
			: A master node is responsible for maintaining the state of the Kubernetes cluster. It typically runs a kube-apiserver, kube-scheduler, kube-controller-manager, and etcd.
			; Kubernetes Worker
			: A worker node is responsible for running the actual applications managed by Kubernetes. It typically runs kubelet, kube-proxy, a container engine (docker, rkt), and other plugins for networking (flannel) or cloud integration (CNI)

	Each concept will be covered in more detail below.		Each concept will be covered in more detail below.

Leo: /* Controllers */

2019-09-10T16:21:58Z

Controllers

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	See: https://kubernetes.io/docs/concepts/workloads/controllers/replicaset/		See: https://kubernetes.io/docs/concepts/workloads/controllers/replicaset/

	ReplicaSets ~~defines~~ the number of pod replicas that are running at a given time ~~and~~ is enforced by the Replication Controller. Typically, ReplicaSets are used by Deployments as a mechanism to orchestrate pod creation, deletion, and updates.		ReplicaSets are used if you want to scale your pod (that are stateless and interchangeable) a certain amount. You define the number of pod replicas that are running at a given time which is then enforced by the Replication Controller. Typically, ReplicaSets are used by Deployments as a mechanism to orchestrate pod creation, deletion, and updates.

	==== DaemonSet ====		==== DaemonSet ====
	See: https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/		See: https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/

	DaemonSet ~~defines which~~ Pod ~~will run~~ on ~~some or all~~ Kubernetes Nodes. As nodes are added or removed, Pods will be created or destroyed with it. Some use cases requiring DaemonSets include storage services (glusterd, ceph), monitoring, log collection, etc., on each node.		DaemonSet are used to run a Pod on every Kubernetes Nodes in your cluster. As nodes are added or removed, Pods will be created or destroyed with it. Some use cases requiring DaemonSets include storage services (glusterd, ceph), monitoring, log collection, etc., on each node.

	By default, DaemonSet deploys pods to all nodes in the cluster unless a ~~node-Selector~~ property is set in the pod template. DaemonSet deploys pods on unschedulable nodes because a DaemonSet bypasses the Scheduler completely.		By default, DaemonSet deploys pods to all nodes in the cluster unless a NodeSelector property is set in the pod template. DaemonSet deploys pods on unschedulable nodes because a DaemonSet bypasses the Scheduler completely.


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	app: ssd-monitor		app: ssd-monitor
	spec:		spec:
	nodeSelector:		nodeSelector: # Define your node selector here to exclude / include certain nodes
	disk: ssd		disk: ssd
	containers:		containers:

Leo: /* Controllers */

2019-09-10T16:15:22Z

Controllers

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	=== Controllers ===		=== Controllers ===
	A ~~controller is a reconciliation loop that drives~~ the ~~actual~~ cluster state to the desired ~~cluster~~ state.		A Controller ensures the cluster state matches the desired state using a reconciliation loop.

	~~A few types of controllers are controlled by the~~ following ~~'set'~~ objects.		The following objects utilizes a Controller to perform the necessary updates to maintain the current state.

	==== ReplicaSet ====		==== ReplicaSet ====
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	See: https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/		See: https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/

	DaemonSet defines which Pod will run on some or all Kubernetes Nodes. As nodes are added or removed, Pods will be created or destroyed with it. Some use cases ~~requring~~ DaemonSets include storage services (glusterd, ceph), monitoring, log collection, etc., on each node.		DaemonSet defines which Pod will run on some or all Kubernetes Nodes. As nodes are added or removed, Pods will be created or destroyed with it. Some use cases requiring DaemonSets include storage services (glusterd, ceph), monitoring, log collection, etc., on each node.

	By default, DaemonSet deploys pods to all nodes in the cluster unless a node-Selector property is set in the pod template. DaemonSet deploys pods on unschedulable nodes because a DaemonSet bypasses the Scheduler completely.		By default, DaemonSet deploys pods to all nodes in the cluster unless a node-Selector property is set in the pod template. DaemonSet deploys pods on unschedulable nodes because a DaemonSet bypasses the Scheduler completely.

Leo: /* Others */ StatefulSet

2019-09-10T16:01:44Z

Others: StatefulSet

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	{{code\|kubectl get daemonset}} or {{code\|kubectl get ds}}		{{code\|kubectl get daemonset}} or {{code\|kubectl get ds}}

	==== ~~Others~~ ====		==== StatefulSets ====
	~~Stateful Sets~~: https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/		See Also: https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/
	~~Job Controller: Runs~~ a ~~Pod~~ as a ~~job~~. ~~TBD~~.
			StatefulSets manages Pods requiring a sticky identity. Typically, they are used for Pods that are not interchangeable and requires a persistent identifiers (ie. pod name and DNS name such as database-server-0) and stable storage (ie. a pod always has the same PersistentVolume attached).

			Pod creation by default ({{code\|1=podManagementPolicy=OrderedReady}}) is ordered sequentially starting from {{code\|1=0}} to {{code\|1=N-1}} and conversely, scaling down or termination in reverse from {{code\|1=N-1}} to {{code\|1=0}}. Alternatively, it can be set to start up in parallel ({{code\|1=podManagementPolicy=Parallel}}). Deletion of a StatefulSet may occur in any order.

			Note that, the PersistentVolumes associated with the Pods’ PersistentVolume Claims are not deleted when the Pods, or StatefulSet are deleted. This must be done manually.

			==== Others ====
			There may be other Controllers including:
			* Job Controller, which runs a Pod as a job.

	=== Deployments ===		=== Deployments ===

Leo: /* See Also */ additional reading

2019-09-06T21:48:39Z

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2019-09-01T06:22:48Z

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	* <s>MySQL on Kubernetes https://www.youtube.com/watch?v=J7h0F34iBx0</s> Not exactly beginner friendly. Goes over the MySQLOperator and Vitess		* <s>MySQL on Kubernetes https://www.youtube.com/watch?v=J7h0F34iBx0</s> Not exactly beginner friendly. Goes over the MySQLOperator and Vitess

	[[Category:Linux]]~~{{Navbox Linux}}~~		{{Navbox Linux}}[[Category:Linux]]
	[[Category:Docker]]		[[Category:Docker]]
	[[Category:Todo]]		[[Category:Todo]]

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2019-09-01T05:11:20Z

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	* <s>MySQL on Kubernetes https://www.youtube.com/watch?v=J7h0F34iBx0</s> Not exactly beginner friendly. Goes over the MySQLOperator and Vitess		* <s>MySQL on Kubernetes https://www.youtube.com/watch?v=J7h0F34iBx0</s> Not exactly beginner friendly. Goes over the MySQLOperator and Vitess

	[[Category:Linux]]~~{{Navbox Linux}}~~{{Navbox Linux}}		[[Category:Linux]]{{Navbox Linux}}
	[[Category:Docker]]		[[Category:Docker]]
	[[Category:Todo]]		[[Category:Todo]]

Leo: Text replacement - "Category:Linux" to "Category:Linux{{Navbox Linux}}"

2019-09-01T05:07:20Z

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← Older revision		Revision as of 05:07, 1 September 2019
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	* <s>MySQL on Kubernetes https://www.youtube.com/watch?v=J7h0F34iBx0</s> Not exactly beginner friendly. Goes over the MySQLOperator and Vitess		* <s>MySQL on Kubernetes https://www.youtube.com/watch?v=J7h0F34iBx0</s> Not exactly beginner friendly. Goes over the MySQLOperator and Vitess

	[[Category:Linux]]{{Navbox Linux}}		[[Category:Linux]]{{Navbox Linux}}{{Navbox Linux}}
	[[Category:Docker]]		[[Category:Docker]]
	[[Category:Todo]]		[[Category:Todo]]

← Older revision		Revision as of 21:48, 6 September 2019
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	* <s>MySQL on Kubernetes https://www.youtube.com/watch?v=J7h0F34iBx0</s> Not exactly beginner friendly. Goes over the MySQLOperator and Vitess		* <s>MySQL on Kubernetes https://www.youtube.com/watch?v=J7h0F34iBx0</s> Not exactly beginner friendly. Goes over the MySQLOperator and Vitess

			=== Additional Reading ===
			mirantis.com's blog has some good information.
			* https://www.mirantis.com/blog/kaas-vs-paas-mirantis-kubernetes-as-a-service-vs-openshift/

	{{Navbox Linux}}[[Category:Linux]]		{{Navbox Linux}}[[Category:Linux]]
	[[Category:Docker]]		[[Category:Docker]]
	[[Category:Todo]]		[[Category:Todo]]