> For the complete documentation index, see [llms.txt](https://platform9.com/kb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://platform9.com/kb/pmk/how-to/increase-existing-kubernetes-cluster-node-count-flannel.md).

# Increase Existing Kubernetes Cluster Node Count for Flannel CNI

## Problem

During cluster creation, the container CIDR value for a cluster having Flannel CNI was set to 10.20.0.0/16. This will allow for a maximum of 256 nodes considering the CNI interfaces have a /24 CIDR.

Can the Container CIDR be modified for an existing cluster to say, for example /14 to allow the addition of worker nodes beyond the current limit?

## Environment

* Platform9 Managed Kubernetes - All Versions
* Flannel

## Procedure

{% hint style="warning" %}
**IMPORTANT**

Customers will need to ensure all running pods/workloads within the cluster are terminated prior to this operation.
{% endhint %}

1. Contact Platform9 Support so that they make the changes in the Backend Qbert DB to update the containerCIDR to a new subnet for the cluster.
2. Once the change is done, delete *cni0* and *flannel0* interfaces on all the nodes part of the cluster.

{% tabs %}
{% tab title="None" %}

```none
~$ sudo ip link del cni0
~$ sudo ip link del flannel0
```

{% endtab %}
{% endtabs %}

2. Restart the PMK stack in a rolling fashion on the Master Nodes which will tear down everything including any running pods and starts over again.

{% tabs %}
{% tab title="None" %}

```none
~$ systemctl stop pf9-hostagent pf9-nodeletd
~$ /opt/pf9/nodelet/nodeletd phases stop
~$ systemctl start pf9-hostagent
```

{% endtab %}
{% endtabs %}

4. Perform the same PMK Stack restart operation in batches or all together for the Worker nodes.
5. Post that, ensure that the *cni0* and *flannel0* interfaces comes up with the changed CIDR values.
6. Test the pod deployment and the Pod to Pod connectivity amongst the master and worker nodes.


---

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