I want to expose multiple services trough single load balancer. Each service points to exactly one pod.
So far I tried to:
kubectl expose <podName> --port=7000
And in Azure portal to manually set either load balancing rules or Inbound Nat rules, pointing to exposed pod.
So far I can connect to pod using external IP and specified port.
Depends on how you want to separate services on the same IP. The two ways that come to my mind are :
use NodePort services and then map some ports from your LB to that part on your cluster nodes. This gives separation by port.
way more interesting in my opinion is to use Ingress/IngressController. You would expose only IC on standard ports like 80 & 443 and then it will map to your services by hostname and uri
In Azure container service, Azure will use Load Balancer to expose k8s services, like this:
root#k8s-master-E27AE453-0:~# kubectl get svc
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
jasonnginx 10.0.41.194 52.226.33.200 8080:32011/TCP 4m
kubernetes 10.0.0.1 <none> 443/TCP 11m
mynginx 10.0.144.49 40.71.230.60 80:32366/TCP 5m
yournginx 10.0.147.28 40.71.226.23 80:32289/TCP 4m
root#k8s-master-E27AE453-0:~#
Via Azure portal, check Azure load balancer frontend IP configuration(different IP address):
ACS will create Load Balancer rules and add rontend IP address automatically.
How to expose multiple kubernetes services trough single azure load
balancer?
ACS expose k8s services through that Azure Load Balancer, do you mean you want to expose k8s services with a single Public IP address?
If you want to expose k8s services with a single public IP address, as Radek said, maybe you should use Nginx Ingress Controller.
The Ingress Controller works like this:
Thanks guys. I think I have found viable solution to my problem. I should have been more specific about what I'm going to do.
I want to host game server over UDP. So any kubernetes ingress controller is not really an option, since they rarely support UDP routing.
I also don't need to host multitude of services on single machine 1-4 of pods per single node is probably the maximum.
I have found about using :
hostNetwork: true
in yaml config and it actually works pretty well for this scenario.
I get IP directly from host node. I can then select matching node within load balancer and create NAT or load balancing rule
Create multiple nodePort type service, and fix the nodePort.
And the cloud load balancer, set multiple listener groups. The listen port is same as the service's nodeport, and the target are all the worker nodes.
Related
I have a separate VM in the same network as my kubernetes in Azure.
I have a kafka pod and I am able to reach this pod using the IP. The problem is that the pod IP is changing all the time.
Is there any way to get the correct IP each time the pod IP is changing?
I would suggest using a kubernetes service to expose pod. This avoids the problem with change in POD IP because service IP does not change.
Kubernetes ServiceTypes allow you to specify what kind of Service you want. The default is ClusterIP.
Type values and their behaviors are:
ClusterIP: Exposes the Service on a cluster-internal IP. Choosing this value makes the Service only reachable from within the cluster. This is the default ServiceType.
NodePort: Exposes the Service on each Node's IP at a static port (the NodePort). A ClusterIP Service, to which the NodePort Service routes, is automatically created. You'll be able to contact the NodePort Service, from outside the cluster, by requesting :.
LoadBalancer: Exposes the Service externally using a cloud provider's load balancer. NodePort and ClusterIP Services, to which the external load balancer routes, are automatically created.
ExternalName: Maps the Service to the contents of the externalName field (e.g. foo.bar.example.com), by returning a CNAME record
Since you are accessing the POD from outside the kubernetes cluster itself use NodePort or LoadBalancer type service.
As mentioned by #arghya-sadhu already going for Kubernetes service, is the best option. The kubernetes service has an IP depending on the type of kubernetes service.
For services of type ClusterIP, you get a cluster IP address
For services of type Load Balancer, you get a Loadbalancer IP address (i.e) public IP address
For services of type NodePort, you can access using the node's address.
But, whatever the type of service is, you can access the service using the kube-DNS within the cluster. So, let's say your service name is other-service and it exposes port 8080, running on namespace abc, then you can access the service as follows:
http://other-service.abc:8080
Since, your VM runs outside the cluster, it is better to use Loadbalancer and access the pod using Loadbalancer url or IP address. You can set an ingress in case there are multiple pods in the cluster that you want to connect to.
I was going through Docker and Kubernetes . I want to create two Python web servers and need to access them using public URL and these requests should be balanced between two servers.
I created one Python server and initially deployed that with Docker containers and all this I'm doing using AWS ec2 instance so when I tried to send a request I used ec2publicip:port. This is working which means I created one web server and similarly I will do the same for the second server.
My question is If I deploy this with Kubernetes - Is there any way to do load balancing the Python web servers within the pod. If so, can someone tell me how to do this?
If you create two replicas of the pod via a kubernetes deployment and create a service of type LoadBalancer an ELB on AWS is automatically provisioned.Then whenever a request comes to the ELB on AWS it will distribute the traffic to the replicas of the pod. With a loadbalancer type service you get advanced load balancing capabilities at layer 7. Without a loadbalancer type service or an ingress you get round robin load balancing at layer 4 offered by kube proxy.
Problem with loadbalancer type service is that it will create new ELB for each service which is costly. So I recommend using ingress controller such as Nginx and expose the Nginx Ingress controller via a single loadbalancer on AWS. Then create ingress resource and use path or host based routing to send traffic to pods behind a clusterIP type service.
I have Azure Kubernetes cluster and i want to expose my services.How can i expose them with 1 IP and nodePorts ? My services using TCP so i can not use ingress.I do not want to buy an external Load Balancer for every service.Is there a way to achieve this on Azure ?
If there are external IPs that route to one or more cluster nodes, Kubernetes Services can be exposed on those externalIPs. Traffic that ingresses into the cluster with the external IP (as destination IP), on the Service port, will be routed to one of the Service endpoints. externalIPs are not managed by Kubernetes and are the responsibility of the cluster administrator.
you can use external-ips to access your application with http://External_IP:ServicePort
Explaining my confusion / lack of understanding
When reading about the external LoadBalancer in K8s, which is a cloud provider only feature, I don't quite understand when it should be used, as when one creates a Deployment K8s will do Round Robin load balancing on the pods in that Deployment.
So from my current understanding all one would need to do is make a NodeIP, and you have the equivalent of an external load balancer?
Or should I think of the LoadBalancer type as haproxy/nginx/Envoy, where one can do SSL, reverse proxy, and many other useful things?
My current guess is that the proper use of LoadBalancer is to add many NodeIP's, but I can't find anything to back that up.
Question
Can anyone explain when and why to use LoadBalancer and not just using the NodeIP?
For example, You want to deploy multiple applications in your cluster, say 10 apps.
You would like to access these 10 apps over internet. One way is to set those 10 application services as nodeport so you can access them from outside. For this to happen kubernetes opens 10 nodeports on each cluster node. This is a security risk.
In most of the enterprises where they work behind firewall in a closed network dont allow external traffic to/from any ports other than http/https ( 80/443 ).
One way is to set service type as Loadbalancer for each application service. So, to access 10 app, you will be provisioning 10 load balancers to access the app servers over http/https ports. Since loadbalancers are charged resources, economically it is not viable to have one load balancer for each service that you want to access over itnernet.
Is there a way to access all those 10 app services running inside kubernetes over single port. This is where ingress controller comes into picture.
Ingress controller allows single ip-port to access all services running in k8s through ingress rules. The ingress controller service is set to load balancer so it is accessible from public internet
How to add multiple ingress or Load balancers in kubernetes for separate services,
here is the post who I ended up creating a ingress to my sub-domain. Is there any way we can specific the same IP address created by GCE to launch multiple Ingress resources.
I am using GCE for hosting my cluster. If there is a better way to handle this scenario to have multiple resources to expose a service with a sub-domain www.app1.domain.com, www.app2.domain.com which are entirely different apps and have two ingress resources that point to two these specific services using same external IP address.
From the post I could able to create but unable to specify the external IP address to it.
Any help is much appreciated, thank you.
You can just define multiple Ingress resources and put them to Kubernetes - they don't have to be in the same yaml file. All ingress resources share the same proxy and they are routed via the defined hostname and path to the wanted service.
I am not sure what you mean with the external IP address.