I have a K8s cluster running with a few services in it. BEcause of K8s DNS, within the cluster services can talk to each over via HTTP request with their name as the URL (e.g http://foo-bar-svc). This is great because I don't need to use an IP address, which I'm assuming would change every time a pod gets redeployed.
Now I want a Cloud Function to be able to post a request to one of these service.
I've followed this guide and successfully created a VPC Connector.
From my Cloud Function, I can make a HTTP request to a service in my K8s cluster, but only if I use an explicit IP address.
How can I instead use one of the URLS that the K8s DNS can resolve?
The best way to expose a k8s service with ingoing host request, is ingress.
You can define a Ingress ressource link with your service, example:
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
name: simple-fanout-example
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /
spec:
rules:
- host: foo.bar.com
http:
paths:
- path: /foo
backend:
serviceName: service1
servicePort: 4200
- path: /bar
backend:
serviceName: service2
servicePort: 8080
In this example we define a host foo.bar.com to resolve and depends of the path /foo or /bar we reroute to a service behind. Of course you can replace it by the prefixe "/*" for reroute all to one specific service path.
Please refer the documentation: https://kubernetes.io/docs/concepts/services-networking/ingress/
But with this configuration you need to have a Load balancer in front and an alias to a DNS entry:
https://cloud.google.com/kubernetes-engine/docs/concepts/ingress?hl=en
And to be more resilience you can add one ingress controller (nginx,traefik....): https://kubernetes.io/docs/concepts/services-networking/ingress-controllers/
So, the schema will be:
DNS server <-> Client resolv DNS -> LB -> Ingress Controller -> Service -> Pod -> container.
I hope it helps.
Related
I have a microk8s running on my raspberry pi and I'm hoping to use a traefik ingressroute to expose kubernetes API to my subdomain
below is my ingressroute:
apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
name: kube-api
spec:
entryPoints:
- web
- websecure
routes:
- match: Host(`kubernetes.mydomain.com`)
kind: Rule
services:
- kind: Service
name: kubernetes
port: 16443 # have also tried 443
tls:
secretName: kubernetes.mydomain.com
This works fine for my other services+ingressroute but not with the api.
For the kubernetes api I'm only able to see my certificate was successfully generated but the page just displays 'Internal Server Error'
Please let me know what additional information I can provide and I will gladly do so!
This issue was because traefik was trying to connect with kube-apiserver over https.
I had to use a serverTransport to allow insecure communication between traefik and kube-apiserver. This is not a security concern as communication to traefik will verify ssl.
The way to do this can be found at the very bottom of this page.
https://doc.traefik.io/traefik/v2.4/routing/providers/kubernetes-crd/#kind-serverstransport
I'm trying to setup RESTful API application with Kubernetes. I have a barebones setup with a cluster, static IP address, app deployed with exposed service of type NodePort, and an ingress configured with a managed certificate for SSL. I need to enable CORS and I am not yet using nginx. Is it possible, or do I need to install nginx instead of the default gce class?
Here is my ingress.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: artsdata-ingress
annotations:
kubernetes.io/ingress.global-static-ip-name: "artsdasta-static-ip"
networking.gke.io/managed-certificates: artsdata-certificate
ingress.kubernetes.io/enable-cors: "true"
spec:
backend:
serviceName: artsdata-kg
servicePort: 80
To check I am using curl as follows:
curl -H "Access-Control-Request-Method: GET" -H "Origin: http://localhost" --head http://db.artsdata.ca
I am expecting the response to include Access-Control-Allow-*
Currently CORS mechanism is not supported in GCP L7 load balancer, therefore ingress-gce ingress controller does contain appropriate annotation to accomplish this functionality, find here related Stack thread.
If you consider replacing native GCP Ingress class by Nginx Ingress Controller in order to enable Cross-origin requests then you might have to include at least two annotations in the origin Ingress resource definition:
kubernetes.io/ingress.class: "nginx"
nginx.ingress.kubernetes.io/enable-cors: "true"
I've found a great guideline through GCP community tutorials that explains Nginx Ingress Controller implementation procedure in GKE.
There are also the other L7 proxy frameworks available on the market that can leverage CORS requests like Traefik, Skipper, etc.
I am trying to setup an nginx ingress controller in my GKE cluster and I'd like to use a static global IP address but I am struggling figuring it out how.
After a lot of research, most guides/stackoverflow/blogs just say "use the kubernetes.io/ingress.global-static-ip-name annotation on your ingress resource" however that does not do anything.
Below is an example of my Ingress resource
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: my-ingress
namespace: my-namespace
annotations:
kubernetes.io/tls-acme: "true"
kubernetes.io/ingress.class: "nginx"
kubernetes.io/ingress.allow-http: "false"
nginx.org/websocket-services: "ws-svc"
kubernetes.io/ingress.global-static-ip-name: my-global-gce-ip
spec:
tls:
- secretName: my-secret
hosts:
- mysite.com
rules:
- host: mysite.com
http:
paths:
- path: /
backend:
serviceName: web
servicePort: 80
The service always get's an ephemeral IP address which is thrown away whenever I recreate the controller.
I suspect the issue at hand here is that annotation only works for GCE type of Ingress, not nginx (Even though this is stated nowhere)
Next I attempted setting the IP manually in my ingress resource as showsn in this guide yet when I look at the service created, the external IP address just shows as pending which some github issues seem to point is due to the fact that it is a global and not a regional IP.
With all this in mind, is there any way to have a static global ip on a GKE cluster using an nginx ingress controller?
You have to set the static IP as loadBalancerIP in nginx ingress controller, not in ingress-resource (as you did). As per the documentation, Load Balancer IP is the IP address to assign to load balancer (if supported).
https://github.com/helm/charts/tree/master/stable/nginx-ingress
spec:
...
externalTrafficPolicy: Cluster
loadBalancerIP: [your static IP]
sessionAffinity: None
type: LoadBalancer
And make sure your IP is regional and not global. Only GCP load balancers (GCP built-in ingress controller) support global IP.
I'm trying to setup a pod which receives packets for port 1234 coming from external hosts. I confirmed via tcpdump that the packets are indeed arriving at the openshift cluster. Now, I have pod AAAA running already which supposed to get the packets for port 1234 (routed or forwarded from the openshift master). We already have assigned an IP for the pod so the docs below has been followed thoroughly to setup the externalIP, ports, etc. I suspect the issue is with the master-config but I cant paste them here.
My question is what are the configs necessary to be put in place in the master-config in order to route port 1234 packets to pod AAAA.
Tried already below Openshift docs:
https://docs.openshift.com/container-platform/3.3/admin_guide/tcp_ingress_external_ports.html
https://docs.openshift.com/container-platform/3.3/dev_guide/getting_traffic_into_cluster.html#using-ingress-IP-self-service
First of all - You are only referring to a POD. I would recommend to deploy your app as a Deployment rather. Please refer to this and this.
Additionally, in order to expose Deployments to the outside world in Kubernetes you have to establish a Service. It can expose your app in a few different ways. Please read through this for the details.
If you using any standard app you can usually find an example deployment/service by googling the name of the app and 'kubernetes'.
In your master config (etc/origin/master/master-config.yaml), just add
servicesNodePortRange: "1234-1234"
kubernetesMasterConfig:
apiServerArguments:
controllerArguments:
masterCount: 1
masterIP: x.x.x.x
podEvictionTimeout:
proxyClientInfo:
certFile: master.proxy-client.crt
keyFile: master.proxy-client.key
schedulerArguments:
schedulerConfigFile: /etc/origin/master/scheduler.json
servicesNodePortRange: "1234-1234"
servicesSubnet: 172.30.0.0/16
staticNodeNames: []
After that, restart atomic-openshift-master service.
Then, create a second service for your deployment with a load balancer type. Assuming your deployment config name is "myapp", create new file similar below,
--- "new-svc.yml" ----
apiVersion: v1
kind: Service
metadata:
creationTimestamp: null
labels:
app: myapp
template: myapp-template
name: myapp-ext
spec:
ports:
- name: myapp
nodePort: 1234
port: 1234
protocol: TCP
targetPort: 1234
selector:
name: myapp
sessionAffinity: None
type: LoadBalancer
After that, create a new service
#oc create -f new-svc.yml
Finally, expose the new service "myapp-ext" by adding route (1234 <-- 1234).
I'm running on the Google Container Engine platform have an ingress that I would like to have a default backend service for almost all of my domains (there are quite a few, but have another, specific service for one domain on it. Going by my understanding of the ingress user guide (scan for "Default Backends:" in there), the config below should work correctly.
However, it doesn't ever create the second backend. Running kubectl describe ingress on the ingress made and when looking at the LB in the Google console site, only the first "default" backend service is listed. Changing the default one into a rule one fixes the problem but means I have to explicitly list all of the domains I want to support.
So, I'm assuming I have a bug in the config below. If so, what is it?
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: boringsites
spec:
backend:
serviceName: boringsites
servicePort: 80
tls:
- secretName: boringsites-tls
rules:
- host: subdomain.example.com
http:
paths:
- backend:
serviceName: other-svc
servicePort: 80
I just created https://gist.github.com/bprashanth/9f4533b19fd864b723ba0720a3648fa3#file-default-basic-yaml-L94 on kubernetes 1.3 and it works as expected. Perhaps you can debug backwards? Where are you running kube and what version are you using? There is a known and fixed race in 1.2 that you might be running into, especially if you updated the ingress. Also note that you need services of type=nodeport, or the ingress controller on gce will ignore the service you plugged into the reasource.