[Doc] document how to migrate from flannel to calico for existing clusters

[dberardo-com]

not just to start a new cluster from 0, but migrating an existing one.

[brandond]

We do not support changing the CNI on a running cluster, and do not plan on documenting it. I'll convert this to a discussion, if you do come up with some steps that work for you please post them.

[mmuto118]

@dberardo-com
Hi,
Thank you for posting this topic.
I am planning to maigrate from flannel to calico on our runing cluster.
The main reason for this is to get real source ip address by using traefik(Ingress) in calico networking.
you try the bellow procudure?
https://docs.tigera.io/calico/latest/getting-started/kubernetes/flannel/migration-from-flannel

[brandond]

The normal way to get real source address in pods behind a LoadBalancer service is to set ExternalTrafficPolicy=Local:
https://kubernetes.io/docs/tasks/access-application-cluster/create-external-load-balancer/#preserving-the-client-source-ip

Note that changing the CNI isn't required, these steps will actually work with traefik, flannel, and servicelb.

[mmuto118]

@brandond
Thank you for reply.
your advice helps a lot.
I will try the link proveded by you.

[jerome7885]

I beginner in kubernetes, but :
With K3s flannel and ingress-nginx, set ExternalPolicyNetwork at Local. No, problem with the Layer, the problem is Klipper, i know.
Sorry for my bad english. Mais j'ai vraiment tout essayé depuis 5 jours.

[matschen]

@mmuto118 Hello, I’d like to ask whether your issue has been resolved. I’m facing the same situation as well. Thank you!