k8s bare metal cluster installer

DISCLAIMER

NOT INTENDED FOR PRODUCTION USE. For pet projects or testing only.

Description

k8s bare metal cluster installer is intended to help with the installation of the sandbox kubernetes cluster on bare metal infrastructure.

Requirements

• Ubuntu 16.04+ (local and remote)
• sudo access on remote machines

Usage

Installer must be executed locally along with the extra details of the remote host being provided.

Note: installer must be executed as root.

sudo ./k8s-cluster-setup.sh \
    -n <node-name> \
    -h <node-host> \
    -m <node-mode:master/worker> \
    -l <node-label> \
    -u <remote-user> \
    -p <remote-user-password> \
    -i <install-updates:true/false> \
    -o <observability-stack:true/false> \
    -s <observability-stack-node-selector> \
    -c <cleanup:true/false>

• node-name (mandatory) desired name of the node. Will be used to set a hostname of the remote machine, as well as hostname of the local SSH configuration (for maintenance access).
• node-host (mandatory) remote server host where the node must be installed.
• node-mode:master/worker (mandatory) k8s node role (either master or worker).
• node-label (optional) additional node label.
• remote-user (mandatory) user name for remote access with sudo permissions.
• remote-user-password (mandatory) user password for remote access with sudo permissions.
• install-updates:true/false (optional, default: false) whether to install updates or not.
• observability-stack:true/false (optional, default: false) whether to install prometeus, node-exporter and kube-state-metrics.
• observability-stack-node-selector (mandatory if observability-stack=true) target node selector for observability stack.
• cleanup:true/false (optional, default: false) whether to perform post-install cleanup or not (remove installer files).

Every installer execution creates a working directory named after .installations/<node-name>-<node-host> where logs and stages progress is saved. Every log file is named after the timestamp of the installation start.

Stages

Installation process is divided into stages. It is done to separate unrelated steps as well as to make them retryable. Every stage creates completion marker in the working directory.

Stage 1 - prepare OS

This stage validates OS requirements, installs missing software and updates, and sets the hostname of the machine.

Stage 2 - install k8s

This stage installs kubernetes and related software.

Stage 3 - setup k8s maintenance user

This stage creates a separate maintenance user on the remote machine. User name is k8s. Additionally a pair of public/private keys is generated and configured for remote access (keys are located in ~/.ssh/<node-name>).

Stage 4 - configure k8s master

This stage initializes kubernetes master node. Important step here is to save join command that needs to be executed during workers installation. Additionally observability stack may be installed if required. At the end, kube.config will be copied to the installation folder.

Stage 5 - configure k8s worker

This stage joins kubernetes worker node to the kubernetes master node. It is more manual step and requires join command that was generated on the previous stage for mater node.

Stage 6 - demo app

This stage installs a demo app to the newly created cluster.

Stage 7 - disable root access

This stage grants kubernetes cluster maintenance access to k8s user. Also, for security reasons, this stage disables ssh login for root.

Notes

After installation is complete the node can be accessed via ssh using k8s user: ssh <node-name>

License

MIT