PI4 k3s install server currently unable to handle the request

Question

I'm trying to install and run a single-node lightweight kubernetes cluster, to play around with on my Raspberry pi4, of which I found k3s. However, from what I've read or seen, I'm probably missing something, but haven't found reference to the exact problem I'm getting (testing with simple kubectl command after installation):

$ kubectl get nodes
Error from server (ServiceUnavailable): the server is currently unable to handle the request

The installations that I've referenced:

• Turing Pis, multi-node cluster -> The part of knowing and using Ansible currently seems like bit of a overkill)
• Pi setup & k3s install -> Good tutorial, but not having similar config responses?

$ sudo k3s server
INFO[2020-09-30T06:58:13.488363192+01:00] Starting k3s v1.18.9+k3s1 (630bebf9)
INFO[2020-09-30T06:58:13.489450500+01:00] Cluster bootstrap already complete
FATA[2020-09-30T06:58:13.535582640+01:00] starting kubernetes: preparing server: start cluster and https: listen tcp :6443: bind: address already in use

Presumed that this isn't necessary anymore then, based on the newer installation version.

• complete k3s 101 youtube -> Still not magically working, as shown.

So if anyone is able to please help me, or guide me in a direction to better debug and display the problem so that I understand and can fix the problem.

Feedback from the installation didn't display that anything went wrong:

$ sudo curl -sfL https://get.k3s.io | INSTALL_K3S_EXEC="--write-kubeconfig-mode 664" sh -
[INFO]  Finding release for channel stable
[INFO]  Using v1.18.9+k3s1 as release
[INFO]  Downloading hash https://github.com/rancher/k3s/releases/download/v1.18.9+k3s1/sha256sum-arm.txt
[INFO]  Downloading binary https://github.com/rancher/k3s/releases/download/v1.18.9+k3s1/k3s-armhf
[INFO]  Verifying binary download
[INFO]  Installing k3s to /usr/local/bin/k3s
[INFO]  Creating /usr/local/bin/kubectl symlink to k3s
[INFO]  Creating /usr/local/bin/crictl symlink to k3s
[INFO]  Creating /usr/local/bin/ctr symlink to k3s
[INFO]  Creating killall script /usr/local/bin/k3s-killall.sh
[INFO]  Creating uninstall script /usr/local/bin/k3s-uninstall.sh
[INFO]  env: Creating environment file /etc/systemd/system/k3s.service.env
[INFO]  systemd: Creating service file /etc/systemd/system/k3s.service
[INFO]  systemd: Enabling k3s unit
Created symlink /etc/systemd/system/multi-user.target.wants/k3s.service → /etc/systemd/system/k3s.service.
[INFO]  systemd: Starting k3s

After that, trying commands:

$ k3s --version
k3s version v1.18.9+k3s1 (630bebf9)
$ kubectl version
Client Version: version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.9+k3s1", GitCommit:"630bebf94b9dce6b8cd3d402644ed023b3af8f90", GitTreeState:"clean", BuildDate:"2020-09-17T19:04:57Z", GoVersion:"go1.13.15", Compiler:"gc", Platform:"linux/arm"}
Error from server (ServiceUnavailable): the server is currently unable to handle the request
$ sudo kubectl get nodes
Error from server (ServiceUnavailable): the server is currently unable to handle the request
$ sudo k3s kubectl get nodes
The connection to the server 127.0.0.1:6443 was refused - did you specify the right host or port?

And looking with htop, definitely 'something' is happening with k3s servers:

Not sure if anything is missing, or must be changed to hosts, for k3s server + agent on device:

127.0.0.1   localhost
::1     localhost ip6-localhost ip6-loopback
ff02::1     ip6-allnodes
ff02::2     ip6-allrouters

127.0.1.1       raspberrypi

... No clue what to debug further??

Answer 1

After learning a bit more of the installation process, by watching this video (k3s install on Pi4 - live walkthrough), I noticed that k3s runs as a service on raspbian.

meaning you're able to:

# see all listed services, to find the name of the running k3s service
$ systemctl --type=service

# service name ironically being 'k3s', and being able to follow the logs for service
$ journalctl -u k3s -f

However, looking in '/boot/cmdline.txt', these cgroup values where in the file, but after a endline-character, which prohibited the k3s service sufficiently reading from the file. File content required to be:

$ sudo cat /boot/cmdline.txt

console=serial0,115200 console=tty1 root=/dev/mmcblk0p7 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait cgroup_enable=1 cgroup_memory=1 cgroup_enable=memory

With that done, I checked journalctl again for the logs, and noticed significantly other logs, regarding pod's containers etc. Master node being functional!:

$ sudo kubectl get nodes
NAME          STATUS   ROLES    AGE     VERSION
raspberrypi   Ready    master   3m52s   v1.18.9+k3s1

If this still doesn't work, I also saw a recent blog post regarding the same issue (due to raspbian kernal update), where fix is also suggested -> post