Configure MetalLB in your Kubernetes clusters for LoadBalancers. Check the assigned IPs and test connectivity. Avoid IP conflicts.
SRE/Kubernetes Admin
Adonai Costa
Install metallb to get LoadBalancers on your clusters
helm repo add metallb https://metallb.github.io/metallbhelm repo updatefor ctx in kind-demo kind-demo3; do helm install metallb -n metallb --create-namespace metallb/metallb --kube-context=${ctx}done
Create an `ipaddresspool` for each cluster based on its kind docker network, but remember, for each cluster, a different `ipaddresspool` to avoid conflict.
To do this, first discover the IP range of your kind network
docker network inspect kind -f '{{.IPAM.Config}}'{172.17.0.0/16 172.17.0.1 map[]} {fc00:f853:ccd:e793::/64 fc00:f853:ccd:e793::1 map[]}]
Mine is `172.17.0.16`, so I will use it in the IP configuration for my `LoadBalancer` type services.
kubectl --context=kind-demo apply -f - <<EOFapiVersion: metallb.io/v1beta1kind: IPAddressPoolmetadata: name: first-pool namespace: metallb-systemspec: addresses: - 172.17.0.61-172.17.0.70---apiVersion: metallb.io/v1beta1kind: L2Advertisementmetadata: labels: todos: verdade name: example namespace: metallb-systemEOF
AND AFTER....
kubectl --context=kind-demo3 apply -f - <<EOFapiVersion: metallb.io/v1beta1kind: IPAddressPoolmetadata: name: first-pool namespace: metallb-systemspec: addresses: - 172.17.0.71-172.17.0.80---apiVersion: metallb.io/v1beta1kind: L2Advertisementmetadata: labels: todos: verdade name: example namespace: metallb-systemEOF
This is the time for you to validate if your machine can connect to a service in the clusters, of type `LoadBalancer`.
# create a simple deploy:
kubectl create deploy web --image nginx --context=kind-demo
# expose the deploy as a LoadBalancer
kubectl expose deploy web --port 80 --target-port 80 --type LoadBalancer --context=kind-demo
# verify the IP assigned to your service
kubectl get service web --context=kind-demoNAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGEdefault web LoadBalancer 10.101.106.156 172.17.0.61 80:31507/TCP 20s
# run a test to see if it is online
curl 172.17.0.61<!DOCTYPE html><html><head><title>Welcome to nginx!</title><style>html { color-scheme: light dark; } .... bla bla bla bla```
# did it work? You can delete it
kubectl delete deploy,svc web --context=kind-demo
Do the same on the other cluster changing the `--context=kind-demo3`
In case of problems, check:
firewall on your machine
correct network of the docker network kind
if you have properly distributed the `ipaddresspool` in the metallbs, without repeating them in the clusters, the idea is each with its own pool of IPs for LoadBalancers, got it.
We will publish part 3 soon! Stay tuned.
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