Why does kubeadm not start even after disabling swap? - kubernetes

Question

I am trying to install kubernetes with kubeadm in my laptop which has Ubuntu 16.04. I have disabled swap, since kubelet does not work with swap on. The command I used is :
swapoff -a
I also commented out the reference to swap in /etc/fstab.
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/sda1 during installation
UUID=1d343a19-bd75-47a6-899d-7c8bc93e28ff / ext4 errors=remount-ro 0 1
# swap was on /dev/sda5 during installation
#UUID=d0200036-b211-4e6e-a194-ac2e51dfb27d none swap sw 0 0
I confirmed swap is turned off by running the following:
free -m
total used free shared buff/cache available
Mem: 15936 2108 9433 954 4394 12465
Swap: 0 0 0
When I start kubeadm, I get the following error:
kubeadm init --pod-network-cidr=10.244.0.0/16
[init] Using Kubernetes version: v1.14.2
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
error execution phase preflight: [preflight] Some fatal errors occurred:
[ERROR Swap]: running with swap on is not supported. Please disable swap
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
I also tried restarting my laptop, but I get the same error. What could the reason be?

Answer 1

below was the root cause.
detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd".
you need to update the docker cgroup driver.
follow the below fix
cat > /etc/docker/daemon.json <<EOF
{
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2",
"storage-opts": [
"overlay2.override_kernel_check=true"
]
}
EOF
mkdir -p /etc/systemd/system/docker.service.d
# Restart Docker
systemctl daemon-reload
systemctl restart docker

Answer 2

you could try kubeadm reset , then kubeadm init --ignore-preflight-errors Swap .

Answer 3

first try with sudo
sudo swapoff -a
then check if there's anything swapped
cat /proc/swaps
and
free -h