By nicoskaralis
We have a pretty big monolithic web app built in rails with background jobs, recurrent workers, websockets and content delivery. After 4 years it is impossible to maintain such a big structure and updates have been a problem. So I’m migrating the code base to kubernetes and splitting the services by docker containers.
The one web server would be split into 4 different containers, each serving a web app split by different domain. The anycable server (and gRPC provider) for each domain would be in a container on its own. The workers would also be on containers… etc
Since kubernetes have a private network for the containers I’m not too worried about internal communication. My problem is with the load balancer and web servers.
My first attempt was to use nginx-ingress. From what I understand the DOKS automatically maps it to a DO load balancer, which doesn’t allow custom rules that I need, specifically this:
location /cable { proxy_pass http://app1_upstream; proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection “Upgrade”; proxy_set_header Host $host; }
My second option would be to create a droplet, in the same VPC, that will run nginx, create an upstream for each pod that contains a web app and manually handle the “Connection: Upgrade” header
upstream app1_upstream { server 192.168.100.10:8010; } upstream app2_upstream { server 192.168.100.11:8010; } upstream app3_upstream { server 192.168.100.12:8010; }
The problem with that is that I can’t seem to find a reliable way to update the upstream when a container is replaced (for update or failure) or scaled (add or remove replicas)
I’m new to docker and kubernetes. How can I do this structure? Or at least, how can I find materials that can help me with this?
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Hi, Looks like you are trying to use DO Loadbanancer with ingress-nginx controller.
"My first attempt was to use nginx-ingress. From what I understand the DOKS automatically maps it to a DO load balancer, which doesn’t allow custom rules that I need, specifically this: " You do not create or use Loadbalanacer to create your routing rules. After you deploy your Ingress Controller with a Loadbalancer, you have to create a Kubernetes Ingress. Kubernetes Ingress will allow you to do what you are looking for.
After you deploy your Ingress Controller, You can create your Ingress Example:
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
name: rails
namespace: your_namespace
annotations:
nginx.ingress.kubernetes.io/proxy-read-timeout: "3600"
nginx.ingress.kubernetes.io/proxy-send-timeout: "3600"
kubernetes.io/ingress.class: nginx
spec:
rules:
- host: your_domain
http:
paths:
- path: /
backend:
serviceName: name_of_your_rails_service
servicePort: port_of_your_rails_service
- path: /events
backend:
serviceName: "gateway-alias-in-club"
servicePort: 8080
- path: /cable
backend:
serviceName: name_of_your_cable_service
servicePort: port_of_your_cable_service
- path: /your_other_paths
backend:
serviceName: name_of_your_other_service
servicePort: port_of_your_other_service
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