I enabled a service topology in k8s, but when I create the following service the request is not redirected to local pod:
apiVersion: v1
kind: Service
metadata:
name: nginx
spec:
selector:
app: nginx
ports:
- protocol: TCP
port: 80
targetPort: 80
topologyKeys:
- "kubernetes.io/hostname"
Related
I have deployed a nodejs/remix app to the Digitalocean Kubernetes service.
I want all my subdomains to subroute
so xxx.example.com should be rewritten as example.com/xxx. Is it possible to do with kubernetes load balancer?
My current config is
apiVersion: v1
kind: Service
metadata:
name: my-service
spec:
type: LoadBalancer
selector:
app: my-deployment
ports:
- name: http
protocol: TCP
port: 80
targetPort: 3000
I have two pods created with deployment and service. my problem is as follows the pod "my-gateway" accesses the url "adm-contact" of "http://127.0.0.1:3000/adm-contact" which accesses another pod called "my-adm-contact" as can i make this work? I tried the following command: kubectl port-forward my-gateway-5b85498f7d-5rwnn 3000:3000 8879:8879 but it gives this error:
E0526 21:56:34.024296 12428 portforward.go:400] an error occurred forwarding 3000 -> 3000: error forwarding port 3000 to pod 2d5811c20c3762c6c249a991babb71a107c5dd6b080c3c6d61b4a275b5747815, uid : exit status 1: 2022/05/27 00:56:35 socat[2494] E connect(16, AF=2 127.0.0.1:3000, 16): Connection refused
Remembering that the images created with dockerfile are with EXPOSE 3000 8879
follow my yamls:
Deployment my-adm-contact:
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-adm-contact
labels:
app: my-adm-contact
spec:
selector:
matchLabels:
run: my-adm-contact
template:
metadata:
labels:
run: my-adm-contact
spec:
containers:
- name: my-adm-contact
image: my-contact-adm
imagePullPolicy: Never
ports:
- containerPort: 8879
hostPort: 8879
name: admcontact8879
readinessProbe:
httpGet:
path: /adm-contact
port: 8879
initialDelaySeconds: 30
periodSeconds: 10
failureThreshold: 6
Sevice my-adm-contact:
apiVersion: v1
kind: Service
metadata:
name: my-adm-contact
labels:
run: my-adm-contact
spec:
selector:
app: my-adm-contact
ports:
- name: 8879-my-adm-contact
port: 8879
protocol: TCP
targetPort: 8879
type: LoadBalancer
status:
loadBalancer: {}
Deployment my-gateway:
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-gateway
labels:
app: my-gateway
spec:
selector:
matchLabels:
run: my-gateway
template:
metadata:
labels:
run: my-gateway
spec:
containers:
- name: my-gateway
image: api-gateway
imagePullPolicy: Never
ports:
- containerPort: 3000
hostPort: 3000
name: home
#- containerPort: 8879
# hostPort: 8879
# name: adm
readinessProbe:
httpGet:
path: /adm-contact
port: 8879
path: /
port: 3000
initialDelaySeconds: 30
periodSeconds: 10
failureThreshold: 6
Service my-gateway:
apiVersion: v1
kind: Service
metadata:
name: my-gateway
labels:
run: my-gateway
spec:
selector:
app: my-gateway
ports:
- name: 3000-my-gateway
port: 3000
protocol: TCP
targetPort: 3000
- name: 8879-my-gateway
port: 8879
protocol: TCP
targetPort: 8879
type: LoadBalancer
status:
loadBalancer: {}
What k8s-cluster environment are you running this in? I ask because the service.type of LoadBalancer is a special kind: at pod initialisation your cloud provider's admission controller will spot this and add in a loadbalancer config See https://kubernetes.io/docs/concepts/services-networking/service/#loadbalancer
If you're not deploying this in a suitable cloud environment, your services won't do anything.
I had a quick look at your SO profile and - sorry if this is presumptious, I don't mean to be - it looks like you're relatively new to k8s. You shouldn't need to do any port-forwarding/kubectl proxying, and this should be a lot simpler than you might think.
When you create a service k8s will 'create' a DNS entry for you which points to the pod(s) specified by your selector.
I think you're trying to reach a setup where code running in my-gateway pod can connect to http://adm-contact on port 3000 and reach a listening service on the adm-contact pod. Is that correct?
If so, the outline solution is to expose tcp/3000 in the adm-contact pod, and create a service called adm-contact that has a selector for adm-contact pod.
This is a sample manifest I've just created which runs nginx and then creates a service for it, allowing any pod on the cluster to connect to it e.g. curl http://nginx-service.default.svc In this example I'm exposing port 80 because I didn't want to have to modify the nginx config, but the principle is the same.
apiVersion: v1
kind: Pod
metadata:
labels:
app: nginx
name: nginx
spec:
containers:
- image: nginx
imagePullPolicy: Always
name: nginx
ports:
- containerPort: 80
protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
app: nginx
type: ClusterIP
The k8s docs on Services are pretty helpful if you want more https://kubernetes.io/docs/concepts/services-networking/connect-applications-service/
a service can be reached on it's own name from pods in it's namespace:
so a service foo in namespace bar can be reached at http://foo from a pod in namespace bar
from other namespaces that service is reachable at http://foo.bar.svc.cluster.local. Change out the servicename and namespace for your usecase.
k8s dns is explained here in the docs:
https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/
I have taken the YAML you provided and assembled it here.
From another comment I see the URL you're trying to connect to is: http://gateway-service.default.svc.cluster.local:3000/my-adm-contact-service
The ability to resolve service names to pods only functions inside the cluster: coredns (a k8s pod) is the part which recognises when a service has been created and what IP(s) it's available at.
So another pod in the cluster e.g. one created by kubectl run bb --image=busybox -it -- sh would be able to resolve the command ping gateway-service, but pinging gateway-service from your desktop will fail because they're not both seeing the same DNS.
The api-gateway container will be able to make a connect to my-adm-contact-service on ports 3000 or 8879, and the my-adm-contact container will equally be able to connect to gateway-service on port 3000 - but only when those containers are running inside the cluster.
I think you're trying to access this from outside the cluster, so now the port/service types are correct you could re-try a kubectl port-forward svc/gateway-service 3000:3000 This will let you connect to 127.0.0.1:3000 and the traffic will be routed to port 3000 on the api-gateway container.
If you need to proxy to the other my-adm-contact-service then you'll have to issue similar kubectl commands in other shells, one per service:port combination. For completeness, if you wanted to route traffic from your local machine to all three container/port sets, you'd run:
# format kubectl port-forward svc/name src:dest (both TCP)
kubectl port-forward svc/gateway-service 3000:3000
kubectl port-forward svc/my-adm-contact-service 8879:8879
kubectl port-forward svc/my-adm-contact-service 3001:3000 #NOTE the changed local port, because localhost:3000 is already used
You will need a new shell for each kubectl, or run it as a background job.
apiVersion: v1
kind: Pod
metadata:
name: my-adm-contact
labels:
app: my-adm-contact
spec:
containers:
- image: my-contact-adm
imagePullPolicy: Never
name: my-adm-contact
ports:
- containerPort: 8879
protocol: TCP
- containerPort: 3000
protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
name: my-adm-contact-service
spec:
ports:
- port: 8879
protocol: TCP
targetPort: 8879
name: adm8879
- port: 3000
protocol: TCP
targetPort: 3000
name: adm3000
selector:
app: my-adm-contact
type: ClusterIP
---
apiVersion: v1
kind: Pod
metadata:
name: my-gateway
labels:
app: my-gateway
spec:
containers:
- image: api-gateway
imagePullPolicy: Never
name: my-gateway
ports:
- containerPort: 3000
protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
name: gateway-service
spec:
ports:
- port: 3000
protocol: TCP
targetPort: 3000
selector:
app: my-gateway
type: ClusterIP
I am using Kubernetes with Minikube on a Windows 10 Home machine to "host" a gRPC service. I am working on getting Istio working in the cluster and have been running into the same issue over and over and I cannot figure out why. The problem is that once everything is up and running, the Istio gateway uses IPv6, seemingly for no reason at all. IPv6 is even disabled on my machine (via regedit) and network adapters. My other services are accessible from IPv4. Below are my steps for installing my environment:
minikube start
kubectl create namespace abc
kubectl apply -f service.yml -n abc
kubectl apply -f gateway.yml
istioctl install --set profile=default -y
kubectl label namespace abc istio-injection=enabled
Nothing is accessible over the network at this point, until I run the following in its own terminal:
minikube tunnel
Now I can access the gRPC service directly using IPv4: 127.0.0.1:5000. However, accessing the gateway is inaccessible from 127.0.0.1:443 and instead is only accessible from [::1]:443.
Here is the service.yml:
apiVersion: v1
kind: Service
metadata:
name: account-grpc
spec:
ports:
- name: grpc
port: 5000
protocol: TCP
targetPort: 5000
selector:
service: account
ipc: grpc
type: LoadBalancer
---
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
service: account
ipc: grpc
name: account-grpc
spec:
replicas: 1
selector:
matchLabels:
service: account
ipc: grpc
template:
metadata:
labels:
service: account
ipc: grpc
spec:
containers:
- image: account-grpc
name: account-grpc
imagePullPolicy: Never
ports:
- containerPort: 5000
Here is the gateway.yml
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
name: gateway
spec:
selector:
istio: ingressgateway
servers:
- port:
number: 443
name: grpc
protocol: GRPC
hosts:
- "*"
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: virtual-service
spec:
hosts:
- "*"
gateways:
- gateway
http:
- match:
- uri:
prefix: /account
route:
- destination:
host: account-grpc
port:
number: 5000
And here are the results of kubectl get service istio-ingressgateway -n istio-system -o yaml:
apiVersion: v1
kind: Service
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: ...
creationTimestamp: "2021-08-27T01:21:21Z"
labels:
app: istio-ingressgateway
install.operator.istio.io/owning-resource: unknown
install.operator.istio.io/owning-resource-namespace: istio-system
istio: ingressgateway
istio.io/rev: default
operator.istio.io/component: IngressGateways
operator.istio.io/managed: Reconcile
operator.istio.io/version: 1.11.1
release: istio
name: istio-ingressgateway
namespace: istio-system
resourceVersion: "4379"
uid: b4db0e2f-0f45-4814-b187-287acb28d0c6
spec:
clusterIP: 10.97.4.216
clusterIPs:
- 10.97.4.216
externalTrafficPolicy: Cluster
ipFamilies:
- IPv4
ipFamilyPolicy: SingleStack
ports:
- name: status-port
nodePort: 32329
port: 15021
protocol: TCP
targetPort: 15021
- name: http2
nodePort: 31913
port: 80
protocol: TCP
targetPort: 8080
- name: https
nodePort: 32382
port: 443
protocol: TCP
targetPort: 8443
selector:
app: istio-ingressgateway
istio: ingressgateway
sessionAffinity: None
type: LoadBalancer
status:
loadBalancer:
ingress:
- ip: 127.0.0.1
Changing the port number to port 80 resolved my issue. The problem was that my gRPC service was not using HTTPS. Will return if I have trouble once I change the service to use HTTPS.
my deployment yaml:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
spec:
selector:
matchLabels:
app: nginx
replicas: 3
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.7.9
ports:
- containerPort: 80
my service yaml:
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
selector:
app: nginx
ports:
- protocol: TCP
port: 80
targetPort: 80
enter image description here
enter image description here
and then I curl 10.104.239.140, but get an error curl: (7) Failed connect to 10.104.239.140:80; Connection timed out
Who can tell me what's wrong?
welcome to SO. That service you've deployed is of type ClusterIP which means it can only be accessed from within the cluster. In your case, it seems you're trying to access it from outside the cluster and thus the connection timed out.
What you can do is, deploy a service of type NodePort or LoadBalancer to access it from outside the cluster. You can read more about different service types here.
You're service would end up something like this:
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
type: NodePort ## or LoadBalancer(supported by Cloud providers like AWS)
selector:
app: nginx
ports:
- protocol: TCP
port: 80
targetPort: 80
# Optional field
# By default and for convenience, the Kubernetes control plane will allocate a port from a range (default: 30000-32767)
nodePort: 30001
My objective: To expose a pod's(running angular image) port so that I can access it from the host machine's browser.
service.yml:
apiVersion: v1
kind: Service
metadata:
name: my-frontend-service
spec:
selector:
app: MyApp
ports:
- protocol: TCP
port: 8000
targetPort: 4200
Pod's yml:
apiVersion: v1
kind: Pod
metadata:
name: angular.frontend
labels:
app: MyApp
spec:
containers:
- name: angular-frontend-demo
image: angular-frontend-image
ports:
- name: nodejs-port
containerPort: 4200
Weird thing is that doing kubectl port-forward pod/angular.frontend 8000:4200 works. However, my objective is to write that in service.yml
Use Nodeport:
apiVersion: v1
kind: Service
metadata:
name: my-frontend-service
spec:
selector:
app: MyApp
type: NodePort
ports:
- protocol: TCP
port: 8000
targetPort: 4200
nodePort: 30001
then you can access the service on nodeport 30001 on any node of the cluster.
For example the machine name is node01 , you can then do curl http://node01:30001
The service you've defined here is of type ClusterIP (since you haven't set a type in the spec). This means the service is only available and reachable within the cluster. You can use Ingress to make it accessible from outside the cluster, see for example this post showing how to do that for Minikube.