Kubernetes/Networking - Revision history

Pio2pio: /* kube-proxy */

2021-06-04T04:39:09Z

kube-proxy

← Older revision		Revision as of 06:39, 4 June 2021
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	= kube-proxy =		= kube-proxy =
			The Kubernetes network proxy (aka kube-proxy) is a daemon running on each node. It basically reflects the services defined in the cluster and manages the rules to load-balance requests to a service’s backend pods.
			:[[File:ClipCapIt-210604-053707.PNG]]


			It can run in a 3 modes, check [https://www.tigera.io/blog/comparing-kube-proxy-modes-iptables-or-ipvs/ comparison of iptables and IPVS modes]:
			* iptables (default mode)
			* ipvs
			* userspace (“legacy” mode, not recommended anymore)


	<code>kube-proxy</code> is responsible to write ip table rules in every node once you define Service. These ip table rules or ClusterIP points to actual pod IP(The IP assigned by flannel daemon).		<code>kube-proxy</code> is responsible to write ip table rules in every node once you define Service. These ip table rules or ClusterIP points to actual pod IP(The IP assigned by flannel daemon).

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	sh$ iptables-save \| grep <pod-name>		sh$ iptables-save \| grep <pod-name>
	-A KUBE-SERVICES ! -s ...		-A KUBE-SERVICES ! -s ...
	~~...~~add real output~~...~~		<TODO:add real output>
	</source>		</source>

Pio2pio: /* kind: Service networking */

2020-11-12T19:01:55Z

kind: Service networking

← Older revision		Revision as of 21:01, 12 November 2020
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	* [https://kubernetes.io/docs/concepts/services-networking/service/#proxy-mode-iptables proxy-mode-iptables] K8s docs		* [https://kubernetes.io/docs/concepts/services-networking/service/#proxy-mode-iptables proxy-mode-iptables] K8s docs
	* [https://github.com/aws/amazon-vpc-cni-k8s amazon-vpc-cni-k8s]		* [https://github.com/aws/amazon-vpc-cni-k8s amazon-vpc-cni-k8s]
			* [https://cloud.google.com/blog/products/gcp/kubernetes-best-practices-mapping-external-services service.type: externalName] best practices to map external services

Pio2pio: /* DNS */

2020-09-19T08:09:37Z

DNS

Show changes

Pio2pio: /* Troubleshooting */

2020-05-13T18:58:06Z

Troubleshooting

@@ Line 626: / Line 626: @@
 kube-system coredns-bb46f865d-vt82x coredns 2019-12-30T15:56:09.458Z [INFO] 10.1.1.1:45808 - 9 "PTR IN 1.0.20.172.in-addr.arpa. udp 41 false 512" NOERROR qr,aa,rd 114 0.000087131s
 </source>
 = Troubleshooting =
 * [https://gravitational.com/blog/troubleshooting-kubernetes-networking troubleshooting-kubernetes-networking] gravitational.com
 = References =
 *Trafic routing

Pio2pio: /* kind: Service networking */

2020-04-28T18:34:20Z

kind: Service networking

← Older revision		Revision as of 20:34, 28 April 2020
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	In depth:		In depth:
			* [https://kubernetes.io/docs/concepts/services-networking/service/#headless-services Service + diagrams] K8s docs
	* [https://stackoverflow.com/questions/50758122/which-service-is-doing-load-balancing-between-kubernetes-nodes/50760654#50760654 Which service is doing load balancing between kubernetes nodes?] iptables rules		* [https://stackoverflow.com/questions/50758122/which-service-is-doing-load-balancing-between-kubernetes-nodes/50760654#50760654 Which service is doing load balancing between kubernetes nodes?] iptables rules
	* [https://kubernetes.io/docs/concepts/services-networking/service/#proxy-mode-iptables proxy-mode-iptables] K8s docs		* [https://kubernetes.io/docs/concepts/services-networking/service/#proxy-mode-iptables proxy-mode-iptables] K8s docs

Pio2pio: /* References */

2020-04-23T08:23:59Z

References

← Older revision		Revision as of 10:23, 23 April 2020
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	</source>		</source>

			= Troubleshooting =
			* [https://gravitational.com/blog/troubleshooting-kubernetes-networking troubleshooting-kubernetes-networking] gravitational.com
	= References =		= References =
	*Trafic routing		*Trafic routing

Pio2pio: /* kind: Service networking */

2020-04-09T19:32:05Z

kind: Service networking

← Older revision		Revision as of 21:32, 9 April 2020
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	= <code>kind: Service</code> networking =		= <code>kind: Service</code> networking =
	Services allow our pods to move around, get deleted, and replicate, all without having to manually keep track of their IP addresses in the cluster. This is accomplished by creating one gateway to distribute packets evenly across all pods.		Services allow our pods to move around, get deleted, and replicate, all without having to manually keep track of their IP addresses in the cluster. This is accomplished by creating one gateway to distribute packets evenly across all pods.

			In depth:
			* [https://stackoverflow.com/questions/50758122/which-service-is-doing-load-balancing-between-kubernetes-nodes/50760654#50760654 Which service is doing load balancing between kubernetes nodes?] iptables rules
			* [https://kubernetes.io/docs/concepts/services-networking/service/#proxy-mode-iptables proxy-mode-iptables] K8s docs
			* [https://github.com/aws/amazon-vpc-cni-k8s amazon-vpc-cni-k8s]

Pio2pio: /* Port-forward */

2020-02-02T18:58:48Z

Port-forward

← Older revision		Revision as of 20:58, 2 February 2020
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	We can port-forward remote kubernetes service port to local machine. Let's assume we have config like this:		We can port-forward remote kubernetes service port to local machine. Let's assume we have config like this:
	:[[File:ClipCapIt-190808-125049.PNG]]		:[[File:ClipCapIt-190808-125049.PNG]]


	Create port-forwarding, your host will start listening on port TCP:8079. If your pod is exposing port below <1024 you should then you need to specify local port to target pod, then use eg: <code>8089:80</code>. First port is local port, second is the container port.		Create port-forwarding, your host will start listening on port TCP:8079. If your pod is exposing port below <1024 you should then you need to specify local port to target pod, then use eg: <code>8089:80</code>. First port is local port, second is the container port.
	<source lang=bash>		<source lang=bash>
	$ kubectl port-forward front-end 8079		$> kubectl port-forward front-end 8079
	Forwarding from 127.0.0.1:8079 -> 8079		Forwarding from 127.0.0.1:8079 -> 8079
	Forwarding from [::1]:8079 -> 8079		Forwarding from [::1]:8079 -> 8079
	Handling connection for 8079		Handling connection for 8079

	#In a new terminal try to reach to the frond-end		# In a new terminal try to reach to the frond-end
	curl http://localhost:8079		$> curl http://localhost:8079
	</source>		</source>

			;References:
			*[https://kubernetes.github.io/ingress-nginx/user-guide/multiple-ingress/ Multiple Ingress controllers] nGinx

	= Proxy =		= Proxy =

Pio2pio: /* kind: ingress networking */

2020-02-02T18:45:34Z

kind: ingress networking

← Older revision		Revision as of 20:45, 2 February 2020
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	= <code>kind: ingress</code> networking =		= <code>kind: ingress</code> networking =
			Ingress it is configuration for a reverse-proxy; implementation need to plugged in to Kubernetes eg. deploying <code>nginx-ingress-controller</code>.
	:[[File:ClipCapIt-200202-175537.PNG]]		:[[File:ClipCapIt-200202-175537.PNG]]

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	spec:		spec:
	rules:		rules:
	- host: acme.example.com #must be valid domain		- host: acme.example.com # must be valid domain
	http:		http:
	paths:		paths:
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	serviceName: nginx-2		serviceName: nginx-2
	servicePort: 80		servicePort: 80
	- http: #any traffic not matching HEADER: <hostnames> above		- http: # any traffic not matching HEADER: <hostnames> above
	paths:		paths:
	- backend:		- backend:

Pio2pio: /* kind: ingress networking */

2020-02-02T18:42:08Z

kind: ingress networking

← Older revision		Revision as of 20:42, 2 February 2020
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	Ingress YAML spec		Ingress YAML spec
	<~~source~~ lang=yaml>		<syntaxhighlightjs lang=yaml>
	cat > ingress.yml <<EOF		cat > ingress.yml <<EOF
	apiVersion: extensions/v1beta1		apiVersion: extensions/v1beta1
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	servicePort: 80		servicePort: 80
	EOF		EOF
	</~~source~~>		</syntaxhighlightjs>


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	</source>		</source>


			The generated configuration by Ingress can be seen directly within the ingress provider eg. nginx pod
			<source lang=bash>
			# _______nginx-ingress-controller-pod______
			kubectl -n ingress-nginx exec nginx-ingress-controller-748cd7b559-wd6rc cat /etc/nginx/nginx.conf > nginx.conf
			</source>

	= Port-forward =		= Port-forward =