The rancher is a great setup with easy-to-config and magnificent UI and integration with cloud IaaS providers like AWS. I have been a fan of the project since the early state of Rancher in version 1 with cattle style deployment before kubernetes become standard for the community of container orchestration.
Calico is another CNI with many features and flexibility that make it a great choice for cloud environments in pure L3 network level.
This article depends on your networking vision and requirements in the kubernetes cluster, so reading the following articles is necessary for a deep understanding of networking in kubernetes.
Edit This Page Kubernetes approaches networking somewhat differently than Docker does by default. There are 4 distinct…
Configuring the Calico CNI plugins
Path to the file containing the root certificate of the certificate authority (CA) that issued the etcd server…
Depending on the orchestrator plugin, etcd may either be the master data store or a lightweight mirror of a separate…
Flannel vs Calico : A battle of L2 vs L3 based networking
We discuss today the networking in container world and primarily in context of K8s . We are not covering the policies…
Understanding kubernetes networking: ingress
In the first post of this series I described the network that enables pods to connect to each other across nodes in a…
The rancher by default uses the host-local calico plugin which itself uses kubernetes API CIDR address for assigning an IP address to containers. This is a painless simple network for small size k8s clusters but in a complicated scenario, we need different options, such as IP ranges or floating IP address for deployments that we cannot load balance or HA them with nginx ingress.
How to implement calico-ipam in rancher?
In order to use calico-ipam in rancher, we need to have another etcd cluster and to edit some of the variables in calico deployment for kubernetes.
Etcd is installed by RKE(Rancher Kubernetes Engine) in your host, so you can use this secure setup in calico by mounting key and certs in the calico controller and calico-node and address them in configmap or simply put them into configmap or secret , due the educational purpose in this tutorial I using another not-secure etcd pod instead of rke secure etcd.
I put both of calico and etcd deployment in this gist.
important note :
default CIDR of the rancher is 10.43.0.0/16 but if you use another setup tool you can see CIDR with
kubectl cluster-info dump | grep -i cidr
final test and results
I am using the latest current version of calico that is v3.5 , this version support namespace annotation and nodeselector for ippool
for creating rolls we need calicoctl and connecting calicoctl to etcdv3 backend of calico I prefer alias in my shell
now the time is create ippool and annotate them to the namespaces
natOutgoing: true---apiVersion: projectcalico.org/v3
and after create this file simply apply to cluster by
calicoctl appy -f test.yml
now you can see your ippool in etcd with
calicoctl get ipPool
and annotate ippools to namespaces
kubectl annotate namespace external-ns "cni.projectcalico.org/ipv4pools"="["external-pool"]"kubectl annotate namespace internal-ns "cni.projectcalico.org/ipv4pools"="["internal-pool"]"
if everything is ok your new deployment in two namespaces most get a different ip address.