I am having an aks instance running. which I assigned an virtual network to it. So all the Node IPs in the network are good and I can reach them from within the network.
Now I wonder if it is possible to create a 2nd virtual network and tell kubernetes to use it to assign public ips ?
Or maybe is it possible to say that a specific service should always have the same node ip ?
No, this is not supported, you might be able to hack your way through, but certainly not out of the box.
But you can create an internal load balancer for your service in the network and its ip wouldnt change, you do this using a service with an annotation:
---
apiVersion: v1
kind: Service
metadata:
name: name
annotations:
service.beta.kubernetes.io/azure-load-balancer-internal: "true"
spec:
ports:
- port: xxx
selector:
app: name
type: LoadBalancer
Related
In Azure, i am using helm to deploy a service (type=loadbalancer)
Below is the manifest file
apiVersion: v1
kind: Service
metadata:
name: {{ template "app.fullname" . }}-service-lb
labels:
app: {{ template "app.fullname" . }}-service-lb
annotations:
service.beta.kubernetes.io/azure-load-balancer-internal: "true"
spec:
type: LoadBalancer
ports:
- port: {{.Values.appServPort}}
nodePort: {{.Values.lbPort}}
protocol: TCP
selector:
app: {{ template "app.fullname" . }}-service
Is it possible to tell kubernetes cluster to use a specific ip every time as an External IP. Whenever I deploy the service?
/*-- EDITED-- */
Every time the loadbalancer service is deployed, a new External ip is allocated, in my case wanted to specify to use the same ip, and assume that ip address is not used within the network.
/*---- */
My understanding is the Kubernetes cluster will allocate an External Ip everytime its deployed, it not specified in the manifest file.
There is an Azure documentation which details on how to use a static Ip within the manifest file and demo link.
I'm just quoting from the docs
If you would like to use a specific IP address with the internal load
balancer, add the loadBalancerIP property to the load balancer YAML
manifest. In this scenario, the specified IP address must reside in
the same subnet as the AKS cluster and must not already be assigned to
a resource. For example, you shouldn't use an IP address in the range
designated for the Kubernetes subnet.
apiVersion: v1
kind: Service
metadata:
name: internal-app
annotations:
service.beta.kubernetes.io/azure-load-balancer-internal: "true"
spec:
type: LoadBalancer
loadBalancerIP: 10.240.0.25
ports:
- port: 80
selector:
app: internal-app
We have defined our internal Load Balancer.
apiVersion: v1
kind: Service
metadata:
name: ads-aks-test
annotations:
service.beta.kubernetes.io/azure-load-balancer-internal: "true"
spec:
type: LoadBalancer
ports:
- protocol: TCP
port: 9000
selector:
app: ads-aks-test
It has its IP and External IP. We want to access this service from VM in another Virtual Network.
We need to know it's DNS name - fully qualified name in advance because we are deploying multiple applications from deployment platform and we want to know based on its Service Name how we can access it once it is being successfully deployed and not to wait for IP address to be determined (either manually or automatically). So for example that is our APP1, and after that automatically we install application APP2 which needs to reach this service.
So for that reason we would like to avoid using the IP information.
How we can determine what is the service "hostname" by which we will access it from the second application?
Only information in docs which I found is: "If your service is using a dynamic or static public IP address, you can use the service annotation service.beta.kubernetes.io/azure-dns-label-name to set a public-facing DNS label." - but this is for public load balancer which we do not want!
Set up ExternalDNS in your K8s cluster. Here is a guide for Azure Private DNS. This will allow you to update the DNS record for any hostname you pick for the service, dynamically via Kubernetes resources.
Sample config looks like this (excerpted from Azure Private DNS guide)
apiVersion: apps/v1
kind: Deployment
metadata:
name: externaldns
spec:
selector:
matchLabels:
app: externaldns
strategy:
type: Recreate
template:
metadata:
labels:
app: externaldns
spec:
containers:
- name: externaldns
image: k8s.gcr.io/external-dns/external-dns:v0.7.3
args:
- --source=service
- --source=ingress
- --domain-filter=example.com
- --provider=azure-private-dns
- --azure-resource-group=externaldns
- --azure-subscription-id=<use the id of your subscription>
volumeMounts:
- name: azure-config-file
mountPath: /etc/kubernetes
readOnly: true
volumes:
- name: azure-config-file
secret:
secretName: azure-config-file
An internal load balancer makes a Kubernetes service accessible only to applications running in the same virtual network as the Kubernetes cluster.
https://learn.microsoft.com/en-us/azure/aks/internal-lb
it seems you want this configuration? is there a peering? you also need to allow communication in NSG .
you can do kubectl get svc
and use the External IP of service ads-aks-test as in annotation you have mentioned "true" so it will be internal IP.
if you are looking forward to resolving the services name in the same cluster you can use the service name itself.
https://kubernetes.io/docs/concepts/services-networking/service/
you can do something like : your-svc.your-namespace.svc.cluster.local
note it will only work when services are in the same Kubernetes cluster.
I have created a AKS and deployed a simple web server on it with following yaml.
Azure LoadBalancer gives a public IP address to it automatically and works fine.
Now I would like to limit the source IP address so I can access it from a specify IP address only.
I've tried adding a Azure Firewall to the virtual network of AKS (aks-vnet-XXXXXXX) with some network rule but doesn't work.
Creating a NAT rule in Firewall and redirects packets to the LoadBalancer works but I can still access the pod with the Public IP address of the LoadBalancer.
Any suggestions?
apiVersion: v1
kind: Service
metadata:
name: nginx
spec:
type: LoadBalancer
selector:
app: nginx
ports:
- name: http
port: 80
targetPort: 80
---
apiVersion: apps/v1
kind: Deployment
(skipped something not important)
spec:
containers:
- name: nginx
image: nginx:1.17.6
ports:
- containerPort: 80
What you're trying to achieve can be done with NSG (Network Security Group) applied to the subnet where your AKS cluster resides: https://learn.microsoft.com/en-us/azure/aks/concepts-security#network-security
More generic approach with a fine-grained control will require creation of Ingress Controller, creation of an Ingress object for your service and applying ingress.kubernetes.io/whitelist-source-range annotation to it.
We have created the kubernetes cluster on the azure VM, with Kube master and two nodes. We have deployed application and created the service with "NodePort" which works well. But when we try to use the type: LoadBalancer then it create service but the external IP goes pending state. Currently we unable create service type load balance and due this "ingress" nginx controller also going to same state. So we are not sure how do we setup load balancing in this case.
We have tried creating Load Balancer in Azure and trying to use that ip like shown below in service.
kind: Service
apiVersion: v1
metadata:
name: jira-service
labels:
app: jira-software
annotations:
service.beta.kubernetes.io/azure-load-balancer-internal: "true"
spec:
selector:
app: jira-software
type: LoadBalancer
loadBalancerIP: xxx.xxx.xxx.xxx
ports:
- name: jira-http
port: 8080
targetPort: jira-http
similarly we have one more application running on this kube cluster and we want to access application based on the context path.
if we invoke jira it should call backend server jira http://dns-name/jira
if we invoke some other app like bitbucket http://dns-name/bitbukcet
If I understand correctly you used type LoadBalancer in Virtual Machine, which will not work - type LoadBalancer works only in managed Kubernetes services like GKE, AKS etc.
You can find more information here.
I have got the following service for Kubernetes dashboard
Name: kubernetes-dashboard
Namespace: kube-system
Labels: k8s-app=kubernetes-dashboard
kubernetes.io/cluster-service=true
Annotations: kubectl.kubernetes.io/last-applied-configuration={"kind":"Service","apiVersion":"v1","metadata":{"name":"kubernetes-dashboard","namespace":"kube-system","creationTimestamp":null,"labels":{"k8s-app":"k...
Selector: k8s-app=kubernetes-dashboard
Type: NodePort
IP: 10.0.106.144
Port: <unset> 80/TCP
NodePort: <unset> 30177/TCP
Endpoints: 10.244.0.11:9090
Session Affinity: None
Events: <none>
According to the documentation, I ran
az acs kubernetes browse
and it works on http://localhost:8001/ui
But I want to access it outside the cluster too. The describe output says that it is exposed using NodePort on port 30177.
But I'm not able to access it on http://<any node IP>:30177
As we know, expose the service to internet, we can use nodeport and LoadBalancer.
As far as I know, Azure does not support nodeport type now.
But I want to access it outside the cluster too.
we can use LoadBalancer to re-create the kubernetes dashboard, here are my steps:
Delete kubernetes-dashboard via kubernetes UI: select Namespace to kube-system, then select services, then delete it:
Modify Kubernetes-dashboard-service.yaml: SSH master VM, then change type from nodeport to LoadBalancer:
root#k8s-master-47CAB7F6-0:/etc/kubernetes/addons# vi kubernetes-dashboard-service.yaml
apiVersion: v1
kind: Service
metadata:
labels:
kubernetes.io/cluster-service: "true"
k8s-app: kubernetes-dashboard
name: kubernetes-dashboard
namespace: kube-system
spec:
ports:
- port: 80
targetPort: 9090
selector:
k8s-app: kubernetes-dashboard
type: LoadBalancer
start kubernetes browse from CLI 2.0:
C:\Users>az acs kubernetes browse -g k8s -n containerservice-k8s
Then SSH to master VM to check the status:
Now, we can via the Public IP address to browse the UI:
Update:
The following image shows the architecture of azure container service cluster(Kubernetes), we should use Load-Balancer to expose the service to internet.
On second thought, this actually is expected to NOT work. The only public IP in the cluster, by default, is for the load balancer on the masters. And that load balancer obviously is not configured to forward random ports (like 30000-32767 for example). Further, none of the nodes directly have a public IP, so by definition NodePort is not going to work external to the cluster.
The only way you're going to make this work is by giving the nodes public IP addresses directly. This is not encouraged for a variety of reasons.
If you merely want to avoid waiting... then I suggest:
Don't delete the Service. Most dev scenarios should just be kubectl apply -f <directory> in which case you don't really need to wait for the Service to re-provision
Use Ingress along with 'nginx-ingress-controller' so that you only need to wait for the full LB+NSG+PublicIP provisioning once, and then can just add/remove Ingress objects in your dev scenario.
Use minikube for development scenarios, or manually add public ips to the nodes to make the NodePort scenario work.
You can't expose the service via nodeport by running the kubectl expose command, you get a VIP address outside the range of the subnets your cluster sits on... Instead, deploy a service through a yaml file and you can specify an internal load balancer as a type..., which will give you a local IP on the Master subnet, which you can connect to via the internal network...
Or, you can just expose the service with an external load balancer and get a public ip. available on the www.