RKE Cluster with more than 250 Pods per Node

1

Hi there,
I have a general question reguarding the RKE configuration:

Is there a way to go past 250 pods per node?

It would be awesome to have atleast 500 pods per node so I can utilize the full cluster performance. Kinda dont know how to change the podCIDRs from 10.x.x.x/24 to 10.x.x.x/20 inside a imported RKE cluster (canal as CNI Provider).

2

Please see [Solved] Setting Max Pods

For changing the CIDRs, the issue is the default is 10.42.0.0/16 and 10.43.0.0/16. Currently rke doesn’t support changing it after the cluster is build.

3

How about while creating a new Cluster, is it possible to change the CIDR then?
The Cluster CIDR is as default 10.43.0.0/16 in my cluster.yml. I Haven’t found any options to change the Node CIDR inside the cluster.yml.

4

Yes, you can customize the CIDRs when you create the cluster (before nodes are joined)

Note: you will need two ranges that do not overlap and should not be routeable in your network.

5

What option should I use to change the node CIDR?
I haven’t found any options in the Rancher Documentation.
The closest thing is the cluster_cidr option but that sets the CIDR for the whole cluster.

6

Speaking personally, I prefer horizontal scaling rather than vertical but perhaps you have valid reasons for wanting more pods per node ?. If anything, I would say it’s easier to achieve high node density with smaller nodes if that’s a goal, along with reducing the impact of a node failure and making upgrades a bit less fragile. Just my opinion, YMMV.