Fails to run kubeadm init - kubernetes

Question

With reference to https://github.com/kubernetes/kubeadm/issues/1239. How do I configure and start the latest kubeadm successfully?
kubeadm_new.config is generated by config migration:
kubeadm config migrate --old-config kubeadm_default.config --new-config kubeadm_new.config. Content of kubeadm_new.config:
apiEndpoint:
advertiseAddress: 1.2.3.4
bindPort: 6443
apiVersion: kubeadm.k8s.io/v1alpha3
bootstrapTokens:
- groups:
- system:bootstrappers:kubeadm:default-node-token
token: abcdef.0123456789abcdef
ttl: 24h0m0s
usages:
- signing
- authentication
kind: InitConfiguration
nodeRegistration:
criSocket: /var/run/dockershim.sock
name: khteh-t580
taints:
- effect: NoSchedule
key: node-role.kubernetes.io/master
---
apiVersion: kubeadm.k8s.io/v1alpha3
auditPolicy:
logDir: /var/log/kubernetes/audit
logMaxAge: 2
path: ""
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: ""
etcd:
local:
dataDir: /var/lib/etcd
image: ""
imageRepository: k8s.gcr.io
kind: ClusterConfiguration
kubernetesVersion: v1.12.2
networking:
dnsDomain: cluster.local
podSubnet: ""
serviceSubnet: 10.96.0.0/12
unifiedControlPlaneImage: ""
I changed "kubernetesVersion: v1.12.2" in kubeadm_new.config and it seems to progress further and now stuck at the following error:
failed to run Kubelet: Running with swap on is not supported, please disable swap! or set --fail-swap-on flag to false.
How do I set fail-swap-on to FALSE to get it going?

Answer 1

Kubeadm comes with a command which prints default configuration, so you can check each of the assigned default values with:
kubeadm config print-default
In your case, if you want to disable swap check in the kubelet, you have to add the following lines to your current kubeadm config:
---
apiVersion: kubelet.config.k8s.io/v1beta1
kind: KubeletConfiguration
failSwapOn: false

Answer 2

You haven't mentioned why you chose to disable swap.
I wouldn't consider it as a first option - not because memory swap is a bad practice (it is a useful and basic kernel mechanism) but because it seems the Kubelet is not designed to work properly with swap enabled.
K8S is very clear about this topic as you can see in the Kubeadm installation:
Swap disabled. You MUST disable swap in order for the kubelet to work
properly.
I would recommend reading about Evicting end-user Pods and the relevant features that K8S provides to prioritize memory of pods:
1 ) The 3 qos classes - Make sure that your high priority workloads are running with the Guaranteed (or at least Burstable) class.
2 ) Pod Priority and Preemption.