Kubernetes error creating PKI assets: Certificate invalid

I have an issue with joining my worker nodes into the three masters configured. It's worth noting I know very little about the networking side of this (I'd rather it was explained like I am five, so that I can be sure I don't miss anything.)

I've been following the guide located at: https://dockerlabs.collabnix.com/kubernetes/beginners/Install-and-configure-a-multi-master-Kubernetes-cluster-with-kubeadm.html with a few variations - the IP Addresses are different, and the configuration for kubeadm.k8s.io/v1alpha3 isn't supported by the current K8. I've updated to use kubeadm.k8s.io/v1beta3, although two tags from the initial config do not seem to have parallels (apiServerCertSANs and apiServerExtraArgs) and I don't know if those are essential. The Kubectl version I have is 1.24.0

Masters have been initialised with the message:

W0510 09:17:54.102466 8717 initconfiguration.go:306] error unmarshaling configuration schema.GroupVersionKind{Group:"kubeadm.k8s.io", Version:"v1beta3", Kind:"ClusterConfiguration"}: strict decoding error: unknown field "apiServerExtraArgs", unknown field "apiserver-cert-extra-sans" [init] Using Kubernetes version: v1.24.0 [preflight] Running pre-flight checks [preflight] Pulling images required for setting up a Kubernetes cluster [preflight] This might take a minute or two, depending on the speed of your internet connection [preflight] You can also perform this action in beforehand using 'kubeadm config images pull' [certs] Using certificateDir folder "/etc/kubernetes/pki" [certs] Generating "ca" certificate and key [certs] Generating "apiserver" certificate and key [certs] apiserver serving cert is signed for DNS names [kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local master1] and IPs [10.96.0.1 10.50.0.50 10.50.0.10] [certs] Generating "apiserver-kubelet-client" certificate and key [certs] Generating "front-proxy-ca" certificate and key [certs] Generating "front-proxy-client" certificate and key [certs] External etcd mode: Skipping etcd/ca certificate authority generation [certs] External etcd mode: Skipping etcd/server certificate generation [certs] External etcd mode: Skipping etcd/peer certificate generation [certs] External etcd mode: Skipping etcd/healthcheck-client certificate generation [certs] External etcd mode: Skipping apiserver-etcd-client certificate generation [certs] Generating "sa" key and public key [kubeconfig] Using kubeconfig folder "/etc/kubernetes" [kubeconfig] Writing "admin.conf" kubeconfig file [kubeconfig] Writing "kubelet.conf" kubeconfig file [kubeconfig] Writing "controller-manager.conf" kubeconfig file [kubeconfig] Writing "scheduler.conf" kubeconfig file [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [kubelet-start] Starting the kubelet [control-plane] Using manifest folder "/etc/kubernetes/manifests" [control-plane] Creating static Pod manifest for "kube-apiserver" [control-plane] Creating static Pod manifest for "kube-controller-manager" [control-plane] Creating static Pod manifest for "kube-scheduler" [wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s [apiclient] All control plane components are healthy after 6.521293 seconds [upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace [kubelet] Creating a ConfigMap "kubelet-config" in namespace kube-system with the configuration for the kubelets in the cluster [upload-certs] Skipping phase. Please see --upload-certs [mark-control-plane] Marking the node master1 as control-plane by adding the labels: [node-role.kubernetes.io/control-plane node.kubernetes.io/exclude-from-external-load-balancers] [mark-control-plane] Marking the node master1 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule node-role.kubernetes.io/control-plane:NoSchedule] [bootstrap-token] Using token: 1w1x1s.7qwcr1m1e5hj3yp3 [bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles [bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to get nodes [bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials [bootstrap-token] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token [bootstrap-token] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster [bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace [kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key [addons] Applied essential addon: CoreDNS [addons] Applied essential addon: kube-proxy

Your Kubernetes control-plane has initialized successfully!

But all three are listed in the nodes (as NotReady admittedly but I believe that is because I have not deployed something like Calico) and I have reached the point of trying to add in the worker nodes. running the provided join command first gets me the error:

[preflight] Running pre-flight checks [preflight] Reading configuration from the cluster... [preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml' error execution phase preflight: One or more conditions for hosting a new control plane instance is not satisfied.

[failure loading certificate for CA: couldn't load the certificate file /etc/kubernetes/pki/ca.crt: open /etc/kubernetes/pki/ca.crt: no such file or directory, failure loading key for service account: couldn't load the private key file /etc/kubernetes/pki/sa.key: open /etc/kubernetes/pki/sa.key: no such > > file or directory, failure loading certificate for front-proxy CA: couldn't load the certificate file /etc/kubernetes/pki/front-proxy-ca.crt: open /etc/kubernetes/pki/front-proxy-ca.crt: no such file or directory]

Please ensure that:

• The cluster has a stable controlPlaneEndpoint address.
• The certificates that must be shared among control plane instances are provided.

To see the stack trace of this error execute with --v=5 or higher

To fix this, I copied the certificates from one of the master onto the worker at /etc/kubernetes/pki/ I then ran the join again, and got the following error:

[preflight] Running pre-flight checks [preflight] Reading configuration from the cluster... [preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml' [preflight] Running pre-flight checks before initializing the new control plane instance error execution phase preflight: [preflight] Some fatal errors occurred: [ERROR ExternalEtcdClientCertificates]: /etc/etcd/ca.pem doesn't exist [ERROR ExternalEtcdClientCertificates]: /etc/etcd/kubernetes.pem doesn't exist [ERROR ExternalEtcdClientCertificates]: /etc/etcd/kubernetes-key.pem doesn't exist [preflight] If you know what you are doing, you can make a check non-fatal with --ignore-preflight-errors=... To see the stack trace of this error execute with --v=5 or higher

Again, I copied the certificates from the master at /etc/etcd/ . Finally, I get this error:

[preflight] Running pre-flight checks [preflight] Reading configuration from the cluster... [preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml' [preflight] Running pre-flight checks before initializing the new control plane instance [preflight] Pulling images required for setting up a Kubernetes cluster [preflight] This might take a minute or two, depending on the speed of your internet connection [preflight] You can also perform this action in beforehand using 'kubeadm config images pull' [certs] Using certificateDir folder "/etc/kubernetes/pki" [certs] Using the existing "front-proxy-client" certificate and key error execution phase control-plane-prepare/certs: error creating PKI assets: failed to write or validate certificate "apiserver": certificate apiserver is invalid: x509: certificate is valid for kubernetes, kubernetes.default, kubernetes.default.svc, kubernetes.default.svc.cluster.local, master2, not worker1 To see the stack trace of this error execute with --v=5 or higher

If I copy the certificates from a given master it shows up as valid for that master (master2 above). How do I generate/use certificates on the worker as it seems these are generated by the INIT command, rather than the JOIN command?

As a potential solution I looked at turning off SSL internally, as per this post https://stackoverflow.com/questions/60970744/how-to-run-kubernetes-without-ssl-network but I cannot find the relevant sections in my YAML to amend. I'd rather run with SSL if I can, but I'm open for how to disable it if required.