kubernetes k3s agent can't connect to master CA/SSL error - nginx

Question

I am trying to deploy an application with k3s kubernetes. Currently I have two master nodes behind a load-balancer, and I have some issues connecting worker nodes to them. All nodes and the load-balancer runs in seperate vms.
The load balancer is a nginx server with the following configuration.
load_module /usr/lib/nginx/modules/ngx_stream_module.so;
events {}
stream {
upstream k3s_servers {
server {master_node1_ip}:6443;
server {master_node2_ip}:6443;
}
server {
listen 6443;
proxy_pass k3s_servers;
}
}
the master nodes connects through the load-balancer, and seemingly it works as expected.
ubuntu#ip-172-31-20-78:/$ sudo k3s kubectl get nodes
NAME STATUS ROLES AGE VERSION
ip-172-31-33-183 Ready control-plane,master 81m v1.20.2+k3s1
ip-172-31-20-78 Ready control-plane,master 81m v1.20.2+k3s1
However the worker nodes yields an error about the SSL certificate?
sudo systemctl status k3s-agent
● k3s-agent.service - Lightweight Kubernetes
Loaded: loaded (/etc/systemd/system/k3s-agent.service; enabled; vendor preset: enabled)
Active: active (running) since Sun 2021-01-24 15:54:10 UTC; 19min ago
Docs: https://k3s.io
Process: 3065 ExecStartPre=/sbin/modprobe br_netfilter (code=exited, status=0/SUCCESS)
Process: 3066 ExecStartPre=/sbin/modprobe overlay (code=exited, status=0/SUCCESS)
Main PID: 3067 (k3s-agent)
Tasks: 6
Memory: 167.3M
CGroup: /system.slice/k3s-agent.service
└─3067 /usr/local/bin/k3s agent
Jan 24 16:12:23 ip-172-31-27-179 k3s[3311]: time="2021-01-24T16:34:02.483557102Z" level=info msg="Running load balancer 127.0.0.1:39357 -> [104.248.34.
Jan 24 16:12:23 ip-172-31-27-179 k3s[3067]: time="2021-01-24T16:12:23.313819380Z" level=error msg="failed to get CA certs: Get \"https://127.0.0.1:339
level=error msg="failed to get CA certs: Get "https://127.0.0.1:39357/cacerts": EOF"
if I try to change K3S_URL in /etc/systemd/system/k3s-agent.service.env to use http, I get an error saying that only https is accepted.

Answer 1

Using the IP Address instead of the hostname in k3s-agent.service.env works for me. Not really a solution as much as a workaround.
/etc/systemd/system/k3s-agent.service.env
K3S_TOKEN='<token>'
K3S_URL='192.168.xxx.xxx:6443'