K8s - How trigger refresh of LoadBalancer svc IP?

spoovy

5/3/23, 9:51 AM

I'm using metallb to assign IPs to LoadBalancers in a home lab k8s cluster. I've had to shrink the IP pool though as I need to use some of them in another test cluster.

I've done this but the IPs of the existing LB svcs have remained the same afterwards -- I need to give the LB svcs a kick somehow to get them to request new IPs. How can I do this?

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Mikołaj Głodziak

5/3/23, 11:11 AM

It looks like the answer to your question is contained in this github thread.

Everything should come down to recreate your service with the appropriate configmap. Look at this answer:

Before change

[root@m-k8s ~]# kubectl get services
NAME         TYPE           CLUSTER-IP      EXTERNAL-IP    PORT(S)        AGE
cfgmap-svc   LoadBalancer   10.100.199.95   192.168.1.11   80:31463/TCP   2m5s
kubernetes   ClusterIP      10.96.0.1       <none>         443/TCP        4h13m

Change IP address

[root@m-k8s ~]# cat metallb-l2.yaml | grep 192.168
      - 192.168.1.11-192.168.1.13
[root@m-k8s ~]# sed -i 's/11/101/;s/13/103/' metallb-l2.yaml
[root@m-k8s ~]# cat metallb-l2.yaml | grep 192.168
      - 192.168.1.101-192.168.1.103

Just apply
kubectl apply -f metallb-l2.yaml

Delete and revise by kubelet

[root@m-k8s ~]# kubectl delete pods --all -n metallb-system
pod "controller-65895b47d4-l5xnn" deleted
pod "speaker-bk8gr" deleted
pod "speaker-bksns" deleted
pod "speaker-c2z6z" deleted
pod " speaker-chlt5" deleted
pod "speaker-scx6x" deleted

Recreate svc

[root@m-k8s ~]# kubectl delete service cfgmap-svc
service "cfgmap-svc" deleted
[root@m-k8s ~]# kubectl expose deployment cfgmap --type=LoadBalancer --name=cfgmap-svc --port=80
service/cfgmap-svc exposed

Check svc

[root@m-k8s ~]# kubectl get svc
NAME          TYPE           CLUSTER-IP       EXTERNAL-IP     PORT(S)        AGE
cfgmap-svc3   LoadBalancer   10.104.192.184   192.168.1.101   80:31440/TCP   8s
kubernetes    ClusterIP      10.96.0.1        <none>          443/TCP        4h34m

You can also look at this github issue. Note, it is old thread.

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spoovy

5/3/23, 11:51 AM

Thanks this pointed me in the right direction. In fact all I had to do was delete the pods (I'd already updated the configmap). `kubectl -n metallb delete pod --all` The services all obtained new IPs from the new pool once the new metallb pods were running.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: K8s - How trigger refresh of LoadBalancer svc IP?

TH: K8s - ทริกเกอร์รีเฟรช LoadBalancer svc IP อย่างไร

RO: K8s - Cum declanșează reîmprospătarea IP-ului LoadBalancer svc?

RU: K8s - Как запустить обновление IP-адреса LoadBalancer svc?

VI: K8s - Cách kích hoạt làm mới LoadBalancer svc IP?

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