How to Seamlessly Migrate Calico from etcd to Kubernetes Datastore

Prerequisites

Assume you have a running Kubernetes cluster, Calico using etcd as its datastore, and

calicoctl

installed.

Check Current Datastore

Verify the current storage backend by inspecting the Calico node daemonset for etcd environment variables.

<code>kubectl -n kube-system get ds calico-node -oyaml | grep -A3 "ETCD_"</code>

Migration Steps

Lock the etcd datastore

<code>$ calicoctl datastore migrate lock
Datastore locked.</code>

Export data from etcd

<code>$ calicoctl datastore migrate export > etcd-data</code>

Configure calicoctl for Kubernetes datastore

<code>$ calicoctl get ippool -owide</code>

Import data into Kubernetes

<code>$ DATASTORE_TYPE=kubernetes KUBECONFIG=~/.kube/config calicoctl datastore migrate import -f etcd-data
Datastore locked.
Successfully applied 5 resource(s)
Importing IPAM resources
Successfully applied 6 IPAM resource(s)
Datastore information successfully imported. Please refer to the datastore migration documentation for next steps.</code>

Verify the import

<code>$ DATASTORE_TYPE=kubernetes KUBECONFIG=~/.kube/config calicoctl get ippool
NAME                 CIDR           SELECTOR
default-ipv4-ippool 10.244.0.0/16  all()</code>

Install Calico using the Kubernetes datastore

<code># Download the Calico manifest for Kubernetes datastore
curl -o /etc/kubernetes/addons/calico.yaml https://raw.githubusercontent.com/projectcalico/calico/v3.27.4/manifests/calico.yaml

# Apply the manifest
kubectl apply -f /etc/kubernetes/addons/calico.yaml</code>

Unlock the datastore

<code>$ DATASTORE_TYPE=kubernetes KUBECONFIG=~/.kube/config calicoctl datastore migrate unlock
Datastore unlocked.</code>

Conclusion

Migrating Calico to use Kubernetes as its datastore reduces the overhead of maintaining a separate etcd cluster, streamlines resource management, and improves overall architecture consistency. Following the steps above ensures a smooth transition.