Networking
==========

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CloudNativePG assumes the underlying Kubernetes cluster has the required
connectivity already set up. Networking on Kubernetes is an important
and extended topic; please refer to the :ref:`Kubernetes documentation <Networking>`  for further
information.

If you’re following the quickstart guide to install CloudNativePG on a
local KinD or K3d cluster, you should not encounter any networking
issues as neither platform will add any networking restrictions by
default.

However, when deploying CloudNativePG on existing infrastructure,
networking restrictions might be in place that could impair the
communication of the operator with PostgreSQL clusters. Specifically,
existing `Network Policies <https://kubernetes.io/docs/concepts/services-networking/network-policies/>`_ 

might restrict certain types of traffic.

Or, you might be interested in adding network policies in your
environment for increased security. As mentioned in the :ref:`security document <Security>`  ,
please ensure the operator can reach every cluster pod on ports 8000 and
5432, and that pods can connect to each other.

Cross-namespace network policy for the operator
-----------------------------------------------

Following the quickstart guide or using helm chart for deployment will
install the operator in a dedicated namespace (``cnpg-system`` by
default). We recommend that you create clusters in a different
namespace.

The operator *must* be able to connect to cluster pods. This might be
precluded if there is a ``NetworkPolicy`` restricting cross-namespace
traffic.

For example, the :ref:`kubernetes guide on network policies <Networking>` 

contains an example policy denying all ingress traffic by default.

If your local kubernetes setup has this kind of restrictive network
policy, you will need to create a ``NetworkPolicy`` to explicitly allow
connection from the operator namespace and pod to the cluster namespace
and pods. You can find an example in the file in this repository. Please
note, you’ll need to adjust the cluster name and cluster namespace to
match your specific setup, and also the operator namespace if it is not
the default namespace.

::


   #  This network policy allows ingress from the CNPG operator

   #  installed in namespace cnpg-system into the pods corresponding

   #  to a cluster named cluster-example

   apiVersion: networking.k8s.io/v1
   kind: NetworkPolicy
   metadata:
     name: allow-operator
   spec:
     podSelector:
       matchLabels:
         cnpg.io/cluster: cluster-example # The label value must be the cluster name
     ingress:
       - from:
           - namespaceSelector:
               matchLabels:
                 kubernetes.io/metadata.name: cnpg-system # Namespace where the operator is deployed
             podSelector:
               matchLabels:
                 app.kubernetes.io/name: cloudnative-pg # Matches the Operator pod
         ports:
           - port: 8000
           - port: 5432

Cross-cluster networking
------------------------

While :ref:`Bootstrapping a Replica Cluster <Bootstrapping a Replica Cluster>`  from another cluster or when using the
``externalClusters`` section, ensure connectivity among all clusters,
object stores, and namespaces involved.

Again, we refer you to the :ref:`Kubernetes documentation <Networking>` 

for setup information.