Understanding use_control_plane_lb = true

[clickersmudge]

Hi,
I have three "control_plane_nodepools" and three "agent_nodepools".
When I enable "use_control_plane_lb = true" in the Hetnzer panel, two load balancers are created "test-control-plane" and "test".

Load Balancer "test-control-plane"
Target:

• test-control-plane-cx21-hel1-hmy
• test-control-plane-cx21-fsn1-tmx
• test-control-plane-cx21-nbg1-pih

Load Balancer "test"

• test-agent-cpx11-fsn1-xqd
• test-agent-cpx11-hel1-ekd
• test-storage-cpx21-fsn1-zgr
• test-agent-cpx11-nbg1-vvf

Shouldn't one "test-control-plane" Load Balancer be created that routes traffic between three "test-control-plane" and "test-control-plane that redirect traffic to "test-agent"?
For which Load Balancer pinned a domain A record ("test-control-plane" or "test")?
When I check IP addresses
https://IP-test-control-plane (Doesn't open anything)
https://IP-test (Traefik 404 page open)
It seems to me that the "test-control-plane" should act as the main one but "test" throws a 404 page.
I do not understand why?

[mysticaltech]

@clickersmudge Thanks for explaining what happens. By three control-plane-nodepools, I guess you mean three control-plane nodepools with one node in each. If that is so, the behavior is correct.

The only reason for activating use_control_plane_lb is to point your kubectl or any services that need to talk to the Kube API in an HA fashion. So it definitely will not respond to regular HTTP traffic. So really not needed in most cases. In the worst case, if the IP of one control-plane node is not responding for some reason, you can just hit the next one. Having an LB randomly point to a healthy control-plane node is a luxury unless you have mission-critical services needing that kind of HA to access the Kube API.

As for the regular lb, it will work great for you when you write an ingress definition and point it to one of your services that expose a deployment, for instance.

[clickersmudge]

Thank you. This repository and yours work is brilliant.

[mysticaltech]

Thanks, @clickersmudge; I really appreciate those kind words! We tried out best 🙏

[maggie44]

Just a huge amount of information here, there are such rich discussions on this repo, it is helping move things along really quickly.

A quick follow up on the HA of the control planes:

The only reason for activating use_control_plane_lb is to point your kubectl or any services that need to talk to the Kube API in an HA fashion.

I assume this is applicable for HA when accessing the control planes externally. I am using the Kube API from inside a pod, would that already be HA?

[mysticaltech]

@maggie44 Good to hear! To answer the first part of your question, yes, the control plane LB is useful for external access. From inside the pod, at least as long as the pod is running, you should have access to the Kube API at all times.

Now HA or not, it depends if you have at least 3 control-plane nodes or not.

[maggie44]

Great, thanks! I have 3 control-planes so should be all set 👍