enhancements VS external-dns

> was always told early on that although they supported vault on kubernetes via a helm chart, they did not recommend using it on anything but EC2 instances (because of "security" which never really made sense their reasoning).

The reasoning is basically that there are some security and isolation guarantees you don't get in Kubernetes that you do get on bare metal or (to a somewhat lesser extent) in VMs.

In particular for Kubernetes, Vault wants to run as a non-root user and set the IPC_LOCK capability when it starts to prevent its memory from being swapped to disk. While in Docker you can directly enable this by adding capabilities when you launch the container, Kubernetes has an issue because of the way it handles non-root container users specified in a pod manifest, detailed in a (long-dormant) KEP: https://github.com/kubernetes/enhancements/blob/master/keps/... (tl;dr: Kubernetes runs the container process as root, with the specified capabilities added, but then switches it to the non-root UID, which causes the explicitly-added capabilities to be dropped).

You can work around this by rebuilding the container and setting the capability directly on the binary, but the upstream build of the binary and the one in the container image don't come with that set (because the user should set it at runtime if running the container image directly, and the systemd unit sets it via systemd if running as a systemd service, so there's no need to do that except for working around Kubernetes' ambient-capability issue).

> It always surprised me how these conversations went. "Well we don't really recommend kubernetes so we won't support (feature)."

0 is not the request we've defined. And that makes sense. Memory QoS has been in alpha since Kubernetes 1.22 (August 2021) and according to the KEP data was still in alpha as of 1.27.

Note: There's actually a Structured Authentication Config established via KEP-3331. It's in v1.28 as a feature flag gated option and removes the limitation of only having one OIDC provider. I may look into doing an article on it, but for now I'll deal with the issue in a manner that should work even with a bit older versions versions of Kubernetes.

Kubernetes supports a skew policy of n+2 between API server and kubelet. This means if your CP and DP are both on 1.20, you could upgrade your control plane twice (1.20 -> 1.21 -> 1.22) before you need to upgrade your data plane. And when it comes time to upgrade your data plane you can jump from 1.20 to 1.22 to minimize update churn. In the future, this skew will be opened to n+3 https://github.com/kubernetes/enhancements/tree/master/keps/sig-architecture/3935-oldest-node-newest-control-plane

The KEP (Kubernetes Enhancement Proposal) is linked to in the PR [1]. From the summary:

> Sidecar containers are a new type of containers that start among the Init containers, run through the lifecycle of the Pod and don’t block pod termination. Kubelet makes a best effort to keep them alive and running while other containers are running.

[1] https://github.com/kubernetes/enhancements/tree/master/keps/...

This is where the new feature of mutable scheduling directives for jobs comes into play. This feature enables the updating of a job's scheduling directives before it begins. Essentially, it allows custom queue controllers to influence pod placement without needing to directly handle the assignment of pods to nodes themselves. To learn more about this check out the Kubernetes Enhancement Proposal 2926.

What your asking is a (vanilla) Kubernetes non-goal, others have mentioned fluxcd and other add ons that provide primitives for dependency aware deployments. The problem space is so large, that it's unreasonable to to address these concerns in Kubernetes itself, instead, make it extensible... Look at this KEP for example: https://github.com/kubernetes/enhancements/issues/753 Sidecar containers have existed, and been named as such since WAY before that KEP's inception, defining what these things should and shouldn't do is largely arbitrary. Aka: your use-case is niche, if you don't like the behavior, use flux or argo, or write something yourself.

If further interested, I may recommend checking out the KEP. I love how they document the decision making, and all these edge cases :).

See https://kubernetes.io/docs/reference/kubectl/conventions/#subresources and https://github.com/kubernetes/enhancements/issues/2590

The second one is a combination of tools: External DNS, cert-manager, and NGINX ingress. Using these as a stack, you can quickly deploy an application, making it available through a DNS with a TLS without much effort via simple annotations. When I first discovered External DNS, I was amazed at its quality.

One of the reasons why I chose Hetzner was that it WAS supported by the ExternalDNS project. I didn't quite understand why the Hetzner provider was pulled, but I saw that an attempt of re-adding it was refused, on the ground that the upcoming webhook architecture would have allowed to better maintain providers.

Write a custom controller for the external DNS controller, or setup some form of ArgoCD app / appset templating.

so I am looking at having an automated way for new routers registered in Traefik to also have the corresponding DNS entry added to my Pihole instance similar to external-dns but obviously, this is exclusive to ingress on k8s environments. my current setup is traefik in a container on unraid.

You technically don’t need to run a load balancer or have a virtual IP for your control plane. If you control your dns, you can add an A record pointing to all IPs for your control plane nodes. It won’t load balance your traffic, but combined with something like External DNS it gives you HA for the control plane.

I normally deploy external-dns, which automatically updates DNS with the ingress controller's external IP address.

Background: Having a look I can see this https://github.com/kubernetes-sigs/external-dns

3) Use the Kubernetes External-DNS. I've never used this, but this is assuming it can update DNS for each pods/app to point to the correct Node (it'd need to update my Homelab DNS running on Windows Server)

So here’s the solution I have taken for our current stack. EKS and its dependencies are created through terraform using the eks module as well as provision a route53 subdomain and a wildcard cert. Once we have that created, I have installed this deployment into the cluster via the helm module: https://kubernetes-sigs.github.io/aws-load-balancer-controller/v2.4/. This allows me to use kuberentes resources (load balancers or ingress objects) and it will handle all the provisioning of load balancers and security groups for me, based on my application yaml and annotations. We also use https://github.com/kubernetes-sigs/external-dns to manage all of our specific host names for the applications through annotations. So to generally put, terraform manages out Kubernetes clusters, and Kubernetes manages the deployment of anything needed for the application including volumes, load balancers, hostnames though Kubernetes system deployments

Metallb for your load balancer (layer2 mode will do) NginX-ingress, will be spot on for internal home apps External-dns to publish your dns record to your Dns server at home, https://github.com/kubernetes-sigs/external-dns