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I have installed kubernetes on digital ocean cloud. I installed both flannel and calico as CNI. Will, that causes any problems in my cluster?

AATHITH RAJENDRAN
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  • What did you intend to achieve by doing this? – Henry Dec 21 '18 at 04:42
  • Generally this is done to integrate with an existing Vxlan network but to get Calico's network policy engine. – coderanger Dec 21 '18 at 04:43
  • i was learning about kubernetes, so I tried installing both the CNI's to check whether its working or not. now I can't remove calico or flannel from my cluster, if it causes any problem I need to take actions and that's the reason for my question here. @henry – AATHITH RAJENDRAN Dec 21 '18 at 05:14

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Calico and Flannel uses different default IP subnets and CNI driver binaries, they will not work together on the same cluster if you deploy them using standard (not Canal) installations. But it's required for Kubernetes cluster to have one of the network add-on installed. You are not limited to use Flannel or Calico add-ons, there are more of them

To remove Calico or Flannel from the cluster usually it's enough to run kubectl delete -f <calico-or-flannel.yaml> and reboot all nodes to get rid of interfaces created by Calico or Flannel. You may need to rejoin worker nodes to the cluster after that.

VAS
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  • Thanks for this! Not sure why the Calico documentation doesn't provide the ```kubectl delete -f ``` information as an uninstall. I had started a cluster and realized after I got Calico running on the master that it doesn't support Windows for networking, only policy. – duct_tape_coder Mar 05 '19 at 22:18
  • Okay actually, using the delete option with the original yaml didn't completely remove calico from the cluster. It left behind all the pods and daemonsets. I think for me it'll be easier to tear down the cluster and restart. – duct_tape_coder Mar 05 '19 at 22:30
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You can use them together, but make sure you configure things so that Calico isn't trying to control tunneling or routing. This joint configuration is sometimes called "Canal", but you can find the docs most on the Calico side at https://docs.projectcalico.org/v3.4/getting-started/kubernetes/installation/flannel

coderanger
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