K3s on a Centos vm

Sep 27, 2020 linux k3s

This post is about installing lightweight Kubernetes (K3s) on our new vm.

K3s

The previous post was all about being able to install Kubernetes quickly. For that I will use k3s from Rancher because it is fast. Let's go!

Prepare

We do this for testing so we can safely disable the firewall and SELinux on our CentOS vm. This is because SELinux is still experimental in K3s. We also need to enable ssh password authentication so we can issue scp commands from our host machine. For this we just add the following lines to the extra script part of our Vagrantfile:

 1$extra = <<-EXTRA
 2dnf update -y && dnf install vim net-tools git lsof tar -y
 3sed -i 's/enforcing/disabled/g' /etc/selinux/config
 4sed -i 's/PasswordAuthentication\s.*no/PasswordAuthentication yes/g' /etc/ssh/sshd_config
 5systemctl disable firewalld
 6systemctl restart sshd
 7reboot
 8EXTRA
 9
10Vagrant.configure("2") do |config|
11  config.vm.define "node01" do |node01_config|
12    node01_config.vm.box ="generic/centos8"
13    node01_config.vm.hostname = "centos01"
14    node01_config.vm.provider :libvirt do |domain|
15      domain.memory = 4096
16      domain.cpus = 2
17      domain.nested = true
18      domain.volume_cache = 'none'
19    end
20  end
21  config.vm.provision "shell", inline: $extra
22end

Now log on the the virtual machine and issue these commands:

1curl -sfL https://get.k3s.io | sh -s - --write-kubeconfig-mode 644
2sudo cp /etc/rancher/k3s/k3s.yaml ~/.kube/config

Now wait a bit. Once ready, you can issue:

1kubectl get pods --all-namespaces

Manage K3s from the host

1 scp vagrant@192.168.122.232:/home/vagrant/.kube/config .

Edit the config and change the 127.0.0.1 address from the server to the ip address of your vm. (Mine is 192.168.122.232)

Then run:

1kubectl get pods --kubeconfig config --all-namespaces

Hooray!

k3s