I have 3 containers on ECS: web, api and nginx. Basically nginx is proxying traffic to web and api containers:
upstream web {
server web-container:3000;
}
upstream api {
server api-container:3001;
}
But every time I redeploy web or api they change their IPs so I need to redeploy nginx afterwards in order to make it to "pick up" new IPs.
Is there a way to avoid this so I could just update let's say api service and nginx service would automatically proxy to correct IP address?
I assume these containers belong to 3 different task definitions and ultimately 3 different tasks (or better 3 different services).
If that is the setup then you want to use service discovery for this. This only works with ECS services and the idea is that you create 3 distinct services each with 1+ tasks in it. You give the service a name (e.g. nginx, web, api) and each container in them is going to be able to resolve the other containers by pointing to the fqdn (e.g. api.local). When your container in the nginx service tries to connect to api.local service discovery will resolve that name to the IP of one of the tasks in the ECS service api.
If you want to see an example re how this is setup you can look at this demo app and particularly at this CloudFormation template
Related
I'm currently in the process of migrating 3 applications from Elastic Kubernetes Service (EKS) to ECS Fargate. Each application is built with Node JS .The current setup seems to be only 1 load balancer in front of one application and the other two applications are accessed through that one load balancer. This is currently how all three applications is accessed:
first_app.example.com
first_app.example.com/second_app
first_app.example.com/third_app
The front end of each application is being powered by an nginx proxy in EKS. I'm not entirely sure if I need nginx to be in ECS Fargate because the application load balancer I'm planning on to use will have an SSL cert integrated with it for redirects to HTTPS from HTTP. I'm a little unclear how to approach moving these applications to Fargate. Additionally, the third app has 3 additional functions:
Apollo GraphQL (abstraction layer between the front end & back end)
CSV
File Manager
This functionality also needs to be implemented on the Fargate side.
Currently I have setup one ECS Fargate cluster, one ECS Service, and one task definition. The task definition currently has the following 7 ECR images:
app_one_front_end
app_two_front_end
app_three_front_end
app_three_csv_job
app_three_file_manager_job
app_three_graphql
nginx ??
All of these images are stored in ECR. However I don't believe I need nginx in this Fargate cluster.
I'm a little unsure how to approach the architecture for this set of applications. It seems I can only have one task definition running on a service, that's why all containers were implemented into one task definition. The service can then be associated with an application load balancer where I set path based routing to access each application.
Any advice on how to approach this migration would be appreciated.
Thanks!
Each Kubernetes Replica Set should be converted to an ECS Service. Each Kubernetes Pod would be converted to an ECS Task.
Kubernetes Replica Set == ECS Service
Kubernetes Pod == ECS Task
If you had multiple Replica Sets in Kubernetes, in order to scale your pods independently, then in order to have the same scalability in ECS you would configure them as separate services with independent scaling configurations.
You are correct in that you probably don't need the Nginx container in ECS.
It seems I can only have one task definition running on a service, that's why all containers were implemented into one task definition.
Services can communicate with each other. You would enable ECS Service Discovery to facilitate that. However it is fine to have them all in the same Task/Service if they don't need to be scaled out independently.
Also, multiple services can be associated with a single Application Load Balancer by creating different listener rules in the load balancer that map to different Target Groups, if that is something you need. You might need to have multiple Target Groups even if you only have a single ECS Service, because you will need to map different load balancer listeners to different containers in your task. That basically allows the Application Load Balancer to perform the job that Nginx was doing in Kubernetes.
As far as I know, Instance Management and the Controller have the same functions, which managing NGINX Plus and the Instances. but it does not make more sense.
So my question is
What are the differences between Instance Management and Controller?
What is Ingress Controller?
Nginx Instance Management: NGINX Instance Manager empowers you to
Automate configuration and monitoring using APIs.
For example, if you have multiple servers using Nginx then in Nginx Plus service provides a dashboard where all the events can be monitored, Including spikes on specific events, Or think as one of the servers has not been updated from having multiple VM, monitor the list of inventory. To achieve nginx-agant needs to install along with Nginx server on the host.
Ensure your fleet of NGINX web servers and proxies have fixes for
active CVEs
Seamlessly integrate with third‑party monitoring solutions such as
Prometheus and Grafana for insights
Nginx Controller: NGINX Controller is cloud‑agnostic and includes a set of enterprise‑grade services that give you a clear line of sight to apps in development, test, or production. With per‑app analytics, you gain new insights into app performance and reliability so you can pinpoint performance issues before they impact production.
Example: To enable the ingress you did need an Ingress Controller to enabled first.
Nginx Ingress: Each LoadBalancer service requires its own load balancer with its own public IP address, whereas an Ingress only requires one, even when providing access to dozens of services. When a client sends an HTTP request to the Ingress, the host and path in the request determine which service the request is forwarded to.
For example Google Kubernetes Controller
I'm planning to build a website to host static files. Users will upload their files and I deploy bunch of deployments with nginx images on those to a Kubernetes node. My main goal is for some point, users will deploy their apps to a subdomain like my-blog-app.mysite.com. After some time users can use custom domains.
I understand that when I deploy an nginx image on a pod, I have to create a service to expose port 80 (or 443) to the internet via load balancer.
I also read about Ingress, looks like what I need but I don't think I understand that concept.
My question is, for example if I have 500 nginx pods running (each is a different website), do I need a service for every pod in that node (in this case 500 services)?
You are looking for https://kubernetes.io/docs/concepts/services-networking/ingress/#name-based-virtual-hosting.
With this type of Ingress, you route the traffic to the different nginx instances, based on the Host header, which perfectly matches your use-case.
In any case, yes, assuming your current architecture you need to have a service for each pod. Haven't you considered a different approach? Like having a general listener (nginx instances) and get the correct content based on authorization or something?
I want to use Nginx to load balance a kubernetes deployment.
The deployment is part of a service. It contains pod which can be scaled. I want NGINX to be part of the service without being scaled.
I know that I can use NGINX as an external load balancer by configuring it with external dns resolver. With that it can get the IP of the pods scaled and apply its own load balanced rules.
Is it possible to make NGINX part of the service? Then how to do the DNS resolution to the pods? In that case, which pods the service name is refered to?
I would like to avoid the declaration of two services to keep a single definition of the setup which represent a microservice.
More generally, how can I declare in a same service:
a unit which is scaled
a backend, not scaled
a database, not scaled
Thanks all
You can't have NGINX as part of the service. Service doesn't contain any pods, deployment does. It sounds like you want an ingress service, that would be a load balancer any and all services on the cluster
EDIT:
An ingress controller in essence is a deployment of NGINX exposed publicly as a service acting as a load balancer/fan out. The deployment scans your cluster for ingress resources and reconfigures NGINX to forward requests to appropriate services.
Typically people deploy a single controller that acts as the load balancer for all of your microservices. You can fan out based on DNS, URI, other headers and so on. You can also do TLS termination, add basic auth to specific services, it's even possible to splice in NGINX config snippets directly into the ingress resources.
I am developing an isomorphic app. The key moment here is that js code on frontend server and on client is the same.
Suppose we have the following services:
frontend
backend
comments
database
Of course each of these services lives in it's own docker container.
And there is a need to access backend and comments services from client side (as api.app.com and comments.app.com respectively).
It seems pretty reasonable to use nginx as reverse proxy here. So these are new containers to be added:
nginx
consul
consul-template
registrator
And the last problem is to resolve *.app.com to nginx. How to achieve this without buying app.com domain? Of course solution is to add DNS to each container and to dev host. But what docker container should I use as DNS server?
Or maybe there is better architecture?