The default datastore, Kubernetes API datastore is recommended for on-premises deployments, and supports only Kubernetes workloads; etcd is the best datastore for hybrid deployments.
Allowed values are `kdd` (default) and `etcd`.
Note: using kdd and more than 50 nodes, consider using the `typha` daemon to provide scaling.
To re-define you need to edit the inventory and add a group variable `calico_datastore`
In some cases you may want to add several pools and not have them considered by Kubernetes as external (which means that they must be within or equal to the range defined in `kube_pods_subnet` and `kube_pods_subnet_ipv6` ), it starts with the default IP Pools of which IP range CIDRs can by defined in group_vars (k8s_cluster/k8s-net-calico.yml):
Peers can be defined using the `peers` variable (see docs/calico_peer_example examples).
In order to define global peers, the `peers` variable can be defined in group_vars with the "scope" attribute of each global peer set to "global".
In order to define peers on a per node basis, the `peers` variable must be defined in hostvars.
NB: Ansible's `hash_behaviour` is by default set to "replace", thus defining both global and per node peers would end up with having only per node peers. If having both global and per node peers defined was meant to happen, global peers would have to be defined in hostvars for each host (as well as per node peers)
By default Calico blocks traffic from endpoints to the host itself by using an iptables DROP action. When using it in kubernetes the action has to be changed to RETURN (default in kubespray) or ACCEPT (see <https://github.com/projectcalico/felix/issues/660> and <https://github.com/projectcalico/calicoctl/issues/1389).> Otherwise all network packets from pods (with hostNetwork=False) to services endpoints (with hostNetwork=True) within the same node are dropped.
Calico supports two types of encapsulation: [VXLAN and IP in IP](https://docs.projectcalico.org/v3.11/networking/vxlan-ipip). VXLAN is supported in some environments where IP in IP is not (for example, Azure).
*IP in IP* and *VXLAN* is mutualy exclusive modes.
Configure Ip in Ip mode. Possible values is `Always`, `CrossSubnet`, `Never`.
```yml
calico_ipip_mode: 'Always'
```
Configure VXLAN mode. Possible values is `Always`, `CrossSubnet`, `Never`.
```yml
calico_vxlan_mode: 'Never'
```
If you use VXLAN mode, BGP networking is not required. You can disable BGP to reduce the moving parts in your cluster by `calico_network_backend: vxlan`
Please refer to the official documentation, for example [GCE configuration](http://docs.projectcalico.org/v1.5/getting-started/docker/installation/gce) requires a security rule for calico ip-ip tunnels. Note, calico is always configured with ``calico_ipip_mode: Always`` if the cloud provider was defined.
### Optional : Use Calico CNI host-local IPAM plugin
Calico currently supports two types of CNI IPAM plugins, `host-local` and `calico-ipam` (default).
To allow Calico to determine the subnet to use from the Kubernetes API based on the `Node.podCIDR` field, enable the following setting.
```yml
calico_ipam_host_local: true
```
Refer to Project Calico section [Using host-local IPAM](https://docs.projectcalico.org/reference/cni-plugin/configuration#using-host-local-ipam) for further information.