Say, the pod has one container which hosts a webserver serving static page on port 80.
When creating the pod, how to set a subdomain x.example.com to a pod? Is a service necessary here?
What role does kube-dns play here?
I don't want to do a use nodePort binding. The pod should be accessible to the public via x.example.com. Is it possible to access it at example.com with query param as CIDR?
Assuming you aren't deploying to a cloud environment, you would use an Ingress Controller
Deploy an ingress controller as a standard pod, with a service that uses NodePort or HostPort.
Once you've deployed your ingress controller, you can add an Ingress resource.
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: my-ingress
spec:
rules:
- host: x.example.com
http:
paths:
- path: /
backend:
serviceName: web-app-service
servicePort: 80
Point DNS to the host your ingress controller pod was scheduled on, and you can access the pod on x.example.com
If you're deploying to GKE or AWS etc, you can use a Load Balancer resource
Related
After applying ingress in k8s, I see service address was set to node's IP address?
Firstly, I added ingress controller
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.48.1/deploy/static/provider/baremetal/deploy.yaml
Secondly, I add ingress yml:
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: minimal-ingress1
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /
kubernetes.io/ingress.class: nginx
spec:
rules:
- host: "n1.avocado.work"
http:
paths:
- path: /
pathType: Prefix
backend:
service:
name: node1
port:
number: 80
Then I checked the ingress:
kubectl get ingress minimal-ingress1
The address was the node's IP, Why it's not the master's IP
I tried so many times, all the same result. How can I fix that? Any leads, please?
If you are on bare metal, this is as per design. check this for more info.
MetalLB provides a network load-balancer implementation for Kubernetes
clusters that do not run on a supported cloud provider, effectively
allowing the usage of LoadBalancer Services within any cluster.
This section demonstrates how to use the Layer 2 configuration mode of
MetalLB together with the NGINX Ingress controller in a Kubernetes
cluster that has publicly accessible nodes. In this mode, one node
attracts all the traffic for the ingress-nginx Service IP. See
Traffic policies for more details.
I have a deployment which is WEB API. I apply it to Kubernetes. Then add service.yml file to expose it. It is working. I have 12 microservices. All of them have service and deployment .yaml files.
So what is Ingress controller. Why should I use it?
(Except sidecar proxy like istio. Its perfect for resilince and metrics.)
In order for the Ingress resource to work, the cluster must have an ingress controller running. The controller can be for example Nginx Ingress Controller and it can be adjusted in various ways. After you have deployed the controller, all you need is an Ingress resource object deployed in K8s.
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: ingress-sample
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /
spec:
rules:
- http:
paths:
- path: /api
pathType: Prefix
backend:
service:
name: web-api
port:
number: 80
service.name: web-api is the place where you specify link between the ingress and the service.
I created a service and each service is creating a new load balancer, I don't want to create a new load balancer for each service. For that, I found solution ingress controller but it's not happening.
I will try to describe the objects you need in just words.
You don't need to create a load balancer for each service. When you're using an ingress controller (like nginx), the ingress controller itself will be the type load balancer. All your other services need to be something like ClusterIP type.
Afterwards you can decide how to link your ClusterIP services with the Nginx LoadBalancer: create an ingress for each service or one ingress that exposes each service based on some rule (like paths as #harsh-manvar shows in the post above).
When you say "it's not happening", it would be good if you could provide details on your setup.
In order for Nginx ingress controller to work, it needs to be defined either as a NodePort or LoadBalancer service type. The examples provided in the nginx documentation are using LoadBalancer. However, LoadBalancer only works when your cluster supports this object (that means running in most cloud providers like AWS/GCP/Azure/DigitalOcean or newer versions of minikube). On the other hand, NodePort will expose the ingress controller on the Kubernetes node where it runs (when using minikube, that usually means a VM of sorts which then needs to be port forwarded to be accessible).
To use ingress in a local environment, you can look into minikube. All you need is to run minikube addons enable ingress and it will deploy an nginx controller for you. Afterwards, all you need to do is define an ingress and depending on your setup you may need to use kubectl port-forward to port forward port 80 on an nginx controller pod to a local port on your machine.
There are different types of services: ClusterIP, NodePort, LoadBalancer and ExternalName. You can specify it in spec.type. Actually the default one, when not specified is not LoadBalancer, but ClusterIP, so in your case, simply leave away the type: LoadBalancer definition and use your serviceName as backend in your ingress resource. Example:
spec:
rules:
- host: your.fully.qualified.host.name
http:
paths:
- backend:
serviceName: your-internal-service-name
servicePort: 80
path: /
Keep in mind that for some cloud providers there's also the possibility to use an internal LoadBalancer without a public IP. This is done by adding an annotation to the service configuration. For Azure AKS it looks like this:
metadata:
annotations:
service.beta.kubernetes.io/azure-load-balancer-internal: "true"
For Google's GKE the annotation is cloud.google.com/load-balancer-type: "Internal"
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress
annotations:
kubernetes.io/ingress.class: "nginx"
certmanager.k8s.io/cluster-issuer: wordpress-prod
nginx.ingress.kubernetes.io/rewrite-target: /
spec:
tls:
- hosts:
- test.test.com
secretName: prod
rules:
- host: test.test.com
http:
paths:
- path: /service-1
backend:
serviceName: service-1
servicePort: 80
- path: /service-2
backend:
serviceName: service-2
servicePort: 5000
Sharing here documentation for ingress to target multiple services you can redirect to multi-service.
Using this you can access services like
https://test.test.com/service-1
https://test.test.com/service-2
Following documentation you should do the following.
More information: kubernetes.github.com
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$2
name: rewrite
namespace: default
spec:
rules:
- host: rewrite.bar.com
http:
paths:
- backend:
serviceName: http-svc
servicePort: 80
path: /something(/|$)(.*)
For example, the ingress definition above will result in the following rewrites:
rewrite.bar.com/something rewrites to rewrite.bar.com/
rewrite.bar.com/something/ rewrites to rewrite.bar.com/
rewrite.bar.com/something/new rewrites to rewrite.bar.com/new
I have a problem with ingress. It just doesn't work. How to understand and find
what is wrong?
I have kubernetes bare metal.
Installed helm chart
helm install stable/nginx-ingress --name ingress --namespace nginx-ingress
In the same namespace deployed ingress
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: test-ingress
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /
spec:
rules:
- http:
paths:
- path: /test
backend:
serviceName: efk-kibana
servicePort: 5601
Changed the ingress type of the service from LoadBalancer to NodePort because it was not created otherwise.
After installation
curl http://example.com – get an answer example page.
Now all services work for me through NodePort, for example - myweb.com:31555.
In any tutorials does not write that i need to add something to / etc / hosts or something like that.
Thanks for the help.
If you're using a baremetal cluster, you're missing a piece of the puzzle.
Ingresses lie behind an ingress controller - you still need to expose that using a service with Type=LoadBalancer which isn't possible by default with a cloud provider.
There is however, a solution. MetalLB is a provider which will allow you to specify IPs for services with type LoadBalancer.
If you deploy this with a layer 2 configuration and update your ingress controller deployment, it will work without needing NodePort.
I saw some example where the Kubernetes cluster is installed with ingress controller and then the ingress class is added with annotations and host as below.
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: nginx
spec:
rules:
- host: testsvc.k8s.privatecloud.com
http:
I am not sure which service is installed and which IP is configured with the DNS "k8s.privatecloud.com" so as to route requests?
How the DNS routing "k8s.privatecloud.com" routes requests to Kubernetes cluster? How the ingress to kubernetes bridging works?
Also, There could be many services configured with the hosts rule like,
testsvc.k8s.privatecloud.com
testsvc1.k8s.privatecloud.com
testsvc2.k8s.privatecloud.com
How the subdomain routing works here when we hit the service testsvc.k8s.privatecloud.com or testsvc1.k8s.privatecloud.com ...
Thanks
The DNS for all the hostnames in your given example (e.g. testsvc.k8s.privatecloud.com) would point to the machine or load-balancer through which traffic will reach the Ingress controller's nginx, as is described in the kuberetes Ingress documentation
Subdomain routing is traditionally done via "virtual-hosting", sometimes called "v-host-ing", and the nginx ingress uses the HTTP Host: header to know which backend service should receive that traffic. Some Ingress controllers are able to use SNI for that same trick over https.
In addition to #Matthew L Daniel answer.
The kubernetes Ingress works as a proxy between external network and your cluster. The behavior of the ingress is explained in the object ingress. For example:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: test
annotations:
ingress.kubernetes.io/rewrite-target: /
spec:
rules:
- host: foo.bar.com
http:
paths:
- path: /foo
backend:
serviceName: s1
servicePort: 80
- path: /bar
backend:
serviceName: s2
servicePort: 80
Above it`s explained how to route traffic between 2 backends s1 and s2. Ingress does not hold any information about services except its name and port, every time it needs more details it would need to be requested from the api-server.