install in readme + upgrade minor fix

README.md

@@ -6,28 +6,59 @@ Kubernetes cluster operations over SSH
 
 The goal of this project is to provide a simple tool to provision a Kubernetes cluster on VMs over SSH. By going with a script-based approach, you can easily customize the installation process to fit your needs, and fail fast if something goes wrong.
 
-kubelift aims to be a bridge between the manual operations with `kubeadm` and the automated installation with `kubespray` requiring a lot of setup.
-
-## Overview
-
-kubelift provides scripts for automating the management of Kubernetes clusters over SSH. The scripts handle cluster creation, upgrades, and cleanup tasks, and are designed to work with both on-premise and cloud-based virtual machines.
+`kubelift` aims to be a bridge between the manual operations with `kubeadm` and the automated installation with `kubespray` requiring a lot of setup.
 
 ## Requirements
 
-- A set of VMs with SSH access
+- A set of VM(s) with SSH access
 - Sudo privileges without password prompt (NOPASSWD in sudoers) for the SSH user
 - Internet connectivity on all nodes
 
 ## Features
 
-- **Noninteractive mode**: Supports non-interactive execution for automated deployments
-- **SSH-based Operations**: All operations are performed over SSH for remote management
-- **Input Validation**: Thorough input validation ensures all provided parameters are correct
-- **Modular Design**: Scripts are organized into functions for better maintainability
+- **Noninteractive mode** for automated operations
+- **SSH-based Operations** for secure remote management
+- **Seamless Upgrades** for managing cluster lifecycle
+- **Input Validation** ensures all provided parameters are correct
+- **Modular Design** for better maintainability
+
+## Installation
+
+### Quick Setup
+
+```bash
+curl -LO https://raw.githubusercontent.com/cstanislawski/kubelift/main/kubelift.sh
+chmod +x kubelift.sh
+```
+
+### System-wide Installation
+
+```bash
+sudo curl -L https://raw.githubusercontent.com/cstanislawski/kubelift/main/kubelift.sh -o /usr/local/bin/kubelift
+sudo chmod +x /usr/local/bin/kubelift
+```
 
 ## Usage
 
-Before running any operations, copy `.env.example` to `.env` and fill in the required values.
+```bash
+kubelift --help
+Usage: /usr/local/bin/kubelift [operation] [options...]
+Operations:
+    create                                  Create a new Kubernetes cluster
+    upgrade                                 Upgrade an existing Kubernetes cluster
+    cleanup                                 Remove Kubernetes cluster
+
+Options:
+   -h, --help                               Display this help message
+   --noninteractive <bool>                  Enable or disable noninteractive mode
+   --ssh-user <username>                    Username to use for SSH connection
+   --kubernetes-version <version>           Kubernetes version to install (create/upgrade only)
+   --control-plane-ip <ip>                  Control plane node IP address
+   --worker-ips <ip1,ip2,...>               Worker node IP addresses (create only)
+   --enable-control-plane-workloads <bool>  Enable control plane scheduling (create only)
+   --skip-reqs <bool>                       Skip minimum requirements validation
+   --nuke <bool>                            Perform deep cleanup (cleanup only)
+```
 
 ### Cluster Creation
 
@@ -79,7 +110,8 @@ The upgrade operation will:
 ./kubelift.sh cleanup \
     --noninteractive <true|false> \
     --ssh-user <username> \
-    --control-plane-ip <ip>
+    --control-plane-ip <ip> \
+    --nuke <true|false> # Optional
 ```
 
 The cleanup operation will:
@@ -124,7 +156,7 @@ The scripts use the following environment variables:
 
 Some of the alternatives you could consider are:
 
-- [kubeadm](https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/) - a tool built to provide best-practice "fast paths" for creating Kubernetes clusters, which kubelift is based on
+- [kubeadm](https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/) - a tool built to provide best-practice "fast paths" for creating Kubernetes clusters, which `kubelift` is based on
 - [kubespray](https://github.com/kubernetes-sigs/kubespray) - a set of Ansible playbooks to provision a Kubernetes cluster
 - [kubean](https://github.com/kubean-io/kubean) - an operator for cluster lifecycle management based on kubespray
 - [kops](https://github.com/kubernetes/kops) - CLI to create, destroy, upgrade and maintain production-grade Kubernetes clusters hosted on AWS/GCP with more providers in Beta/Alpha
@@ -151,6 +183,7 @@ Some of the alternatives you could consider are:
 - Add support for more CNI plugins: Calico, Cilium
 - Cluster configuration templating
 - Add support for HA control plane
+- Add downgrades support
 - Assume presence of the flag equals true (e.g. --noninteractive) if the flag is present
 - Add k3s support
 - Add support for more Linux distributions

kubelift.sh

@@ -18,18 +18,18 @@ Usage: $0 [operation] [options...]
 Operations:
     create                                  Create a new Kubernetes cluster
     upgrade                                 Upgrade an existing Kubernetes cluster
-    cleanup                                 Remove Kubernetes cluster while preserving CNI
+    cleanup                                 Remove Kubernetes cluster
 
 Options:
-   -h, --help                              Display this help message
-   --noninteractive <bool>                 Enable or disable noninteractive mode
-   --ssh-user <username>                   Username to use for SSH connection
-   --kubernetes-version <version>          Kubernetes version to install (create/upgrade only)
-   --control-plane-ip <ip>                 Control plane node IP address
-   --worker-ips <ip1,ip2,...>              Worker node IP addresses (create only)
-   --enable-control-plane-workloads <bool> Enable control plane scheduling (create only)
-   --skip-reqs <bool>                      Skip minimum requirements validation
-   --nuke <bool>                           Perform deep cleanup (cleanup only)
+   -h, --help                               Display this help message
+   --noninteractive <bool>                  Enable or disable noninteractive mode
+   --ssh-user <username>                    Username to use for SSH connection
+   --kubernetes-version <version>           Kubernetes version to install (create/upgrade only)
+   --control-plane-ip <ip>                  Control plane node IP address
+   --worker-ips <ip1,ip2,...>               Worker node IP addresses (create only)
+   --enable-control-plane-workloads <bool>  Enable control plane scheduling (create only)
+   --skip-reqs <bool>                       Skip minimum requirements validation
+   --nuke <bool>                            Perform deep cleanup (cleanup only)
 EOF
     exit 0
 }
@@ -366,10 +366,13 @@ function join_worker_nodes() {
 function verify_version_compatibility() {
     local nodes_versions
     nodes_versions=$(ssh -o StrictHostKeyChecking=no "$SSH_USER@$CONTROL_PLANE_IP" \
-        kubectl get nodes -o=jsonpath='{range .items[*]}{.status.nodeInfo.kubeletVersion}{"\n"}{end}' | sort -u)
+        "kubectl get nodes -o jsonpath='{.items[*].status.nodeInfo.kubeletVersion}'") || \
+        error "Failed to get cluster version info"
+
+    [[ -z "$nodes_versions" ]] && error "No nodes found in the cluster"
 
     local current_version
-    current_version=$(echo "$nodes_versions" | head -1)
+    current_version=$(echo "$nodes_versions" | tr ' ' '\n' | sort -u | head -1)
 
     [[ $current_version != "v$KUBERNETES_VERSION" ]] || error "Cluster already at version $KUBERNETES_VERSION"
 
@@ -391,6 +394,18 @@ function upgrade_node_components() {
     ssh -o StrictHostKeyChecking=no "$SSH_USER@$node_ip" bash << EOF
 set -euo pipefail
 
+KUBERNETES_VERSION="$KUBERNETES_VERSION"
+KUBERNETES_VERSION_REPOSITORY="v\${KUBERNETES_VERSION%.*}"
+
+install -m 0755 -d /etc/apt/keyrings
+curl -fsSL "https://pkgs.k8s.io/core:/stable:/\$KUBERNETES_VERSION_REPOSITORY/deb/Release.key" | \
+    gpg --dearmor --yes -o "/etc/apt/keyrings/kubernetes-apt-keyring-\$KUBERNETES_VERSION_REPOSITORY.gpg"
+
+echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring-\$KUBERNETES_VERSION_REPOSITORY.gpg] https://pkgs.k8s.io/core:/stable:/\$KUBERNETES_VERSION_REPOSITORY/deb/ /" | \
+    tee /etc/apt/sources.list.d/kubernetes.list
+
+apt-get update
+
 apt-mark unhold kubeadm && apt-get install -y kubeadm=$KUBERNETES_VERSION-* && apt-mark hold kubeadm
 
 if $is_control_plane; then