text: Cilium integration with Flannel (beta)¶
  This guide contains the necessary steps to run Cilium on top of your Flannel cluster.
  If you have a cluster already set up with Flannel you will not need to install Flannel again.
  This Cilium integration with Flannel was performed with Flannel 0.10.0 and Kubernetes >= 1.9. If you find any issues with previous Flannel versions please feel free to reach out to us to help you.
  Note
  This is a beta feature. Please provide feedback and file a GitHub issue if you experience any problems.
  The feature lacks support of the following, which will be resolved in upcoming Cilium releases:
  - L7 policy enforcement
  Flannel installation¶
  NOTE: If
  kubeadm is used, then pass
  --pod-network-cidr=10.244.0.0/16 to
  kubeadm init to ensure that the
  podCIDR is set.
  kubectl apply -f
  Wait until all pods to be in ready state before preceding to the next step.
  Cilium installation¶
  Download the Cilium release tarball and change to the kubernetes install directory:
  curl -LO tar xzvf 1.6.1.tar.gz cd cilium-1.6.1/install/kubernetes
  Install Helm to prepare generating the deployment artifacts based on the Helm templates.
  Generate the required YAML file and deploy it:
  helm template cilium \ --namespace kube-system \ --set global.flannel.enabled=true \ > cilium.yaml
  Set
  global.flannel.uninstallOnExit=true if you want Cilium to uninstall
  itself when the Cilium pod is stopped.
  If the Flannel bridge has a different name than
  cni0, you must specify
  the name by setting
  global.flannel.masterDevice=....
  Optional step:
  If your cluster has already pods being managed by Flannel, there is also
  an option available that allows Cilium to start managing those pods without
  requiring to restart them. To enable this functionality you need to set the
  value
  global.flannel.manageExistingContainers=true
  Once you have changed the ConfigMap accordingly, you can deploy Cilium.
  kubectl create -f cilium.yaml
  Cilium might not come up immediately on all nodes, since Flannel only sets up the bridge network interface that connects containers with the outside world when the first container is created on that node. In this case, Cilium will wait until that bridge is created before marking itself as Ready.