K3S Setup 
K3S Requirements :
| Resources | Limits |
|---|---|
512MB |
MEMORY (we recommend at least 1GB) |
1CPU |
CPU (we recommend at least 2CPU) |
20GB |
STORAGE |
CPU and Memory
The following are the minimum CPU and memory requirements for nodes in a high-availability K3S server
| Deployment Size | Nodes | VCPUS | RAM |
|---|---|---|---|
| Small | Up to 10 | 2 | 4 GB |
| Medium | Up to 100 | 4 | 8 GB |
| Large | Up to 250 | 8 | 16 GB |
| X-Large | Up to 500 | 16 | 32 GB |
| XX-Large | 500+ | 32 | 64 GB |
Disks
The cluster performance depends on database performance. To ensure optimal speed, we recommend always using SSD disks to back your K3S cluster. On cloud providers, you will also want to use the minimum size that allows the maximum IOPS.
Database
K3S supports different databases including MySQL, PostgreSQL, MariaDB, and etcd, the following is a sizing guide for the database resources you need to run large clusters:
| Deployment Size | Nodes | VCPUS | RAM |
|---|---|---|---|
| Small | Up to 10 | 1 | 2 GB |
| Medium | Up to 100 | 2 | 8 GB |
| Large | Up to 250 | 4 | 16 GB |
| X-Large | Up to 500 | 8 | 32 GB |
| XX-Large | 500+ | 16 | 64 GB |
Single Master Node K3S Install
A single-node server installation is a fully-functional Kubernetes cluster, including all the datastore, control-plane, kubelet, and container runtime components necessary to host workload pods. It is not necessary to add additional server or agents nodes, but you may want to do so to add additional capacity or redundancy to your cluster.
Run this command :
High Available K3S Install
To run K3S in this mode, you must have an odd number of server nodes. We recommend starting with three nodes.
To get started, first launch a server node with the cluster-init flag to enable clustering and a token that will be used as a shared secret to join additional servers to the cluster.
Success
Let's validate everything worked as expected. Run a systemctl status k3s.service and make sure it is active.
After launching the first server, join the second and third servers to the cluster using the shared secret:
curl -sfL https://get.k3s.io | K3S_TOKEN=SECRET sh -s - server --server https://<ip or hostname of server1>:6443
Cluster Access
The kubeconfig file stored at /etc/rancher/k3s/k3s.yaml is used to configure access to the Kubernetes cluster. If you have installed upstream Kubernetes command line tools such as kubectl or helm you will need to configure them with the correct kubeconfig path.This can be done by either exporting the KUBECONFIG environment variable or by invoking the --kubeconfig command line flag. Refer to the examples below for details.
Check to see that the second and third servers are now part of the cluster:
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
server1 Ready control-plane,etcd,master 28m vX.Y.Z
server2 Ready control-plane,etcd,master 13m vX.Y.Z
server3 Ready control-plane,etcd,master 10m vX.Y.Z
K3S Agent Install
To install additional agent nodes and add them to the cluster, run the installation script with the K3S_URL and K3S_TOKEN environment variables. Here is an example showing how to join an agent:
Success
Let's validate everything worked as expected. Run a systemctl status k3s-agent and make sure it is active.
Setting the K3S_URL parameter causes the installer to configure K3S as an agent, instead of a server. The K3S agent will register with the K3S server listening at the supplied URL. if you have not set a stable token the value to use for K3S_TOKEN is stored at /var/lib/rancher/k3s/server/node-token on your server node.
Example