You don't actually worry about the implementation details or the imperative steps to make that state a reality. They are reconciling that and making sure that that is a state that's actually reflected, and then giving you access to that. It's a database to exist or a VM to exist, or something like that. Essentially, what you're doing is you're telling them, I would like this state to be a reality. What does that look like? The most common use case is with the large cloud providers, so AWS, Azure, and GCP. Infrastructure is likely the entry point that many folks have had to a declarative orchestration API. We're going to be specifically talking about two use cases for control planes. What is a control plane? In the Crossplane community, we like to describe a control plane as follows, a declarative orchestration API for really anything. Where do I start? Now that I've heard about what control planes are, why Kubernetes is useful for them, how do I actually go about implementing one within my organization with some tangible steps? What Is a Control Plane? Why does Kubernetes serve as a good foundation for building control planes on top of? Then finally, inspiration. That's going to be, what is a control plane, and why do I need one? Then explanation. I usually go through three stages, motivation. When I give talks, I like to be really specific about what we're going to cover, so you can know if there's going to be value for you in this talk. That is going to serve as a great use case for control planes here. It's going to expand a little bit beyond infrastructure specifically. I'm going to cheat a little bit, I did put an asterisk on infrastructure, because we're going to be talking about control planes in general. I'm going to be talking to you about Kubernetes as a foundation for infrastructure control planes. I'm a staff software engineer at Upbound, which is the company behind the initial launch of the Crossplane project, which is now a CNCF incubating project. However this won't help with failover and redundancy, since failed nodes won't be removed from the record, and some clients might cache the address and not try to re-resolve it, thus further prolonging any outages.Mangum: My name is Dan Mangum. If you really didn't want to have a loadbalancer you might be able to set up a round-robin dns entry with the IP's of all the control plane nodes and try specifying this for the controlPlaneEndpoint value. This also likely affects the PKI generated by kubernetes, as it will need to know a common name/IP that you will access the cluster via to include in the certs it generates for the api nodes, otherwise these won't match up correctly. in environments with enforced node recycling, the ControlPlaneEndpointĬould be used for assigning a stable DNS to the control plane. In a cluster with more than one control plane instances, this field should beĪssigned the address of the external load balancer in front of theĮ.g. In case the ControlPlaneEndpoint is not specified, the AdvertiseAddress + BindPortĪre used in case the ControlPlaneEndpoint is specified but without a TCP port,Į.g. Looking at the kubeadm types definition I found this nice description that clearly explains it:ĬontrolPlaneEndpoint sets a stable IP address or DNS name for the control plane itĬan be a valid IP address or a RFC-1123 DNS subdomain, both with optional TCP port. Is there any such plugin or other way of configuring this behaviour to avoid separate infrastructure for load balancing the API server? So couldn't masters ( -control-plane) join the cluster and use the role label to discover the other control plane nodes? Marking the node as control-plane by adding the taints Marking the node as control-plane by adding the label "/master=''" This is because the mark-control-plane phase does: without -control-plane), then it is not only aware of other nodes in the cluster, but also which ones are masters. * The cluster has a stable controlPlaneEndpoint address.īut if you instead join a worker node (i.e. Unable to add a new control plane instance a cluster that doesn't have a stable controlPlaneEndpoint address One or more conditions for hosting a new control plane instance is not satisfied. It is not possible to join master nodes without having set a controlPlaneEndpoint:
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