I am having hard time in understanding the role of a Load Balancer when used with Ingress Nginx.
I know a Load balancer distributes request over multiple nodes.
i.g, let's say I have two nodes A and B , and they are responisble for processing requests at example.com.
So a load balancer will take request for example.com and distribute among them with help of defined algorithm.
I also understand what an API Gateway is,
i.g., let's say I have one order service and another payment service so an API gateway will get the request for example.com and it will hand over the request for /orders to order service and /payments to payment service.
The Confusion:
Load Balancer(NLB) -> API Gateway -> Services -> order deployment -> which is running two replicas
Who distributes requests in those replicas for /orders
What is the role of load balancer in this case?
Some article suggest to create a service as type Load Balancer what does that mean? What this service will do?
Also, Load Balancer sits outside of the cluster NLB -> [ k8s cluster ], how does it know how to distribute requests?
These collectely could one question, I don't know.
Any kind of explanation would appreciated.
I have gone through many articles and blogs but none talks about complete picture.
Update
Many of my doubts are cleared through this article
Within the cluster a service does load balancing among the replicas.
Source
I still have some questions,
Do I only need a load balacner to expose the ingress controller service?
What if there is some problem with the ingress controller and it restarts.
What will happen will it get a new IP and load balancer will poin to new one or the ip will remain the same?
This article may help : https://aws.amazon.com/blogs/opensource/network-load-balancer-nginx-ingress-controller-eks/
Q: Do I only need a load balacner to expose the ingress controller service?
A: Expose K8s services mainly
Q: What if there is some problem with the ingress controller and it restarts.
A: Problem can appear if new broken changes will be applied, and in this case old controller will still work, but new one will fail to start, therefore you will have to do kubectl describe etc, to understand what is wrong.
Q: What will happen will it get a new IP and load balancer will poin to new one or the ip will remain the same?
A: Why you need LB ip's? Use LoadBalancer DNS.
Related
I have a situation here.
I made 2 environments prod and preprod, both has two vms each (like two nodes per environment).
Now i have to create a Load Balancer keeping those to nodes on the back end. Once of the nodes has SSL configured with a domain name (say example.com).
Its a Pega App Server with two nodes pointing to the same DB on Google SQL. now Client wants a Load Balancer in the front which will share or balance the traffic between these two nodes.
Is that possible?
If yes, the domain name has been registered with the ip of Node1, but Load Balancer will have a different ip right?
So if the Pega URL that was working before https://example.com/prweb will not work, isnt it?
But the requirement is they will just type the domain name and ill access the Pega App via Load balancer, as in, to which Node the requests gonna go.
Is that Possible at all guys?
Guys honestly i am a noob in all these Cloud thing, please if possible help me out. I ould really appriciate it. Thanks.
I tried to create an HTTPS Load Balancer classic and added those two instances in the Backend, but 1 target pool detected out of 2 instances, its showing "instance xxxx is unhealthy for [the ip of the load balancer]
So next i created HTTPS type Load Balancer with Network endpoint group, where i added those two nodes private ip. But not sure how to do it. Please let me know if anybody knows how to do it.
I have setup an External HTTP(S) load balancer with the following:
2 Serverless NEGs, each pointing at a different Cloud Run service in their respective region
1 Backend Service, using the 2 NEGs as 2 Backends
1 Host and path rule that sends everything to the Backend Service
1 HTTPS Frontend pointing at the Host and path rule
At this point, I notice that the traffic is routed to the Cloud Run service closest to the region of the client making the request.
I would like to change that to route 100% of the traffic to one Cloud Run service on day 1, 50% on each service on day 2, and on day 3, route 100% of the traffic to the other Cloud Run service.
It's unclear if an External HTTP(S) load balancer can help with that. And if it can, it's unclear if this should be done in the Backend Service or in the Host and Path rule.
Google Cloud load balancer does not support weighted/percent-based load balancing for the external HTTP(S) LB. This is listed at https://cloud.google.com/load-balancing/docs/features#load_balancing_methods.
Maybe I need to create 2 Backend Services, each pointing at one NEG?
Yes, this is how you would do it if external HTTPS GCLB supported it. You need to create separate backendServices for each serverless NEG and list weightedBackendServices in the route rule of the urlMap object. You can find an example here but I believe it only works for internal load balancer (ILB) currently per the link above.
AFAIK, External HTTPS load balancing can only route to the closest location but not dispatch the traffic according to weight.
In addition, your solution requires to deploy in 2 different regions, because you can't 2 backends in the same region in the same backend service.
The easiest solution for now is to use Cloud Run traffic splitting feature. Route all the traffic to the same service, and then, let the Cloud Run load balancer dispatching the requests.
I am running a microservice application off of AWS ECS. Each microservice currently has its own Load balancer.
There is one main public facing service which the rest of the services communicate with via gateways. Having each service have its own ELB is currently too expensive, is there some way to have only 1 ELB for the public facing service that will route to the other services based off of path. Is this possible without actually having the other service names in the URL. Could a reverse proxy work?
I know this is a broad question but any help would be appreciated
Inside your EC2 panel go to loadbalancers section, choose a loadbalancer and then in listeners tab, there is a button named view/edit rules, there you set conditions to use a single loadbalancer for different clusters/instances of your app. note that for each container you need a target group defined.
You can config loadbalancer to route based on:
Http Headers
Path i.e: www.example.com/a or www.example.com/b
Host Header(hostname)
Query strings
or even source Ip.
That's it! cheers.
Need some serious help here, thanks a lot in advance !
I need to deploy a scalable 3 tier web application on AWS and I am having some doubts/trouble understanding the best practice to design the architecture.
NOTE: As per my understanding, all the backend requests are requested through the browser, after the Frontend server serves html/css/js to the user.
Let me show you what I have come up with till now :
Assuming the above 'note':
Cons (as per my understanding):
All the backend routes will be exposed to the outside world.
Even though backend servers are in private subnet, now that they're being accessed via external load balancer, the endpoints API could be accessed from the users.
How will we route a request from a Load balancer to another Load balancer. Because what I have seen is that you could only route a request to an EC2 instance added in the target group.
To overcome the cons as I think in the above approach, I came up with this architecture instead:
Pros (as per my understanding):
The backend routes are safe (in a way) because we have a way of internally connecting from the frontend to the backend servers(if required).
Cons:
If the request is made from the browser, the endpoints are again exposed.
Solution that I found online:
REAL BIG DOUBT IN THIS LAST ONE
This breaks all the logic of my understanding that : All the requests are made by the browser from the user to the backend because in this the requests to the backend are being routed FROM the frontend servers.
QUESTIONS
What if the backend request (say login) is made by the user from the browser?
How will this work out in such case?
seems like you have done some good work here.
Let me start by making things easy for you:
Users only interact with the Load Balancer: If you want to keep it simple and not break off your frontend asset serving to an external service like CloudFront, which you should if you are starting out, you will be hosting the application only via EC2 instances (application origin, or simply orgin). Your requests would look something like this:
Users <--> ALB <--> EC2
Notice how users never interact with EC2 instances directly, its always via Application Load Balancer (ALB).
If I can oversimply thing, this is how HTTP operates, a request is made to a resource at an IP and the response is sent back from the same resource or IP. So as in your diagram, a request will not be responded back by EC2 but rather be relayed via the ALB.
You don't need NAT gateway: NAT gateway are there to make it possible for resources in provate subnet access the internet. In this case, unless you want your application to access the internet, you don't need NAT gateway. Many large scale applications are actually locked down in part by not keeping this resource at all.
You are still protecting the origin: Given that only the ALB can be accessed over the internet and everything else internal you can structure things here in any way that you want to. you could have few internal microservices that can be used internally without ever being exposed to end users. Note that here request never leaves the VPN.
You can read more about this and build a sample application via the official docs here or access AWS tutorials here.
To me, #3 is the correct solution because it does not expose /api to end users (since you mention "I DO NOT want the users to directly access the /api"). In #1, I don't think you could limit access to /api to only the front-end servers, since security groups work on the whole load balancer, not per-target.
Also, being an Internet-facing load balancer, any requests from the front-end servers to the load balancer in #1 will be referencing the load balancer via public IP addresses. This will cause a 1c/GB charge to go "out of" the VPC and then back in again.
Only #3 correctly refers to back-end resources via private IP addresses. The internal load balancer will be referenced via private IP addresses.
I have a Node-Express website running on a microservices based architecture. I deployed the microservices on Amazon ECS cluster with one EC2 instance. The microservices sit behind an Application Load Balancer that routes external traffic correctly to the services. This system is working as expected except for one problem: I need to make a POST request from one service to the other. I am trying to use axios for this but I don't know what url to post to in axios. When testing locally, I just used axios.post('http://localhost:3000/service2',...) inside service 1 but how should I do it here?
So There are various ways.
1. Use Application Load Balancer behind the service
In this method, you put your micro services behind the load balancer(s) and to send request, you give load balancer URL. You can have path based routing for same load balancer or you can use multiple load balancers.
2. Use Service Discovery
In this method, you let your requester discover it. Now Service discovery can be done in various way like using ALB or Route 53 or ECS or Key Value Store or Configuration Management or Third Party Software such as Consul