docs/doc/source/operations/k8s_cluster.rst

Kubernetes Cluster Guide

StarlingX provides a fully-managed, fully-integrated, ready-to-deploy cloud native platform for the deployment and management of containerized workloads.

This section gives an overview of the Kubernetes cluster in StarlingX and describes how to interface with the cluster.

Kubernetes cluster overview

StarlingX Kubernetes is a private cloud software project that deploys a Kubernetes cluster on dedicated physical servers. With a range of deployment configurations, it can be deployed from the data center to the edge of the network. This provides a single solution to deploy your containerized applications, regardless of where they are located. Its ability to scale both large and small makes StarlingX Kubernetes ideal for edge deployments.

StarlingX Kubernetes provides a fully-managed solution that includes both Day-1 and Day-2 operations with respect to managing a cloud native platform:

• Installation
• Configuration management
• Operational and fault management of all components of the solution
  • Physical servers
  • Operating system and kernel
  • StarlingX software
  • Kubernetes software
  • Supporting open-source software such as Ceph, Apache, and Postgres.
• Log and performance metrics are collected and reported for both hardware and software components.
• Security is addressed across a variety of attack surfaces that includes TLS support, user authentication/authorization, and network firewalls on all external interfaces, with support for technologies such as UEFI Secure Boot, signed software updates.

All of the above solutions are fully-integrated and ready-to-deploy with default configurations that optimize performance and scalability.

All services have been validated together as an integrated system.

The high-level functional overview of StarlingX Kubernetes is shown in the figure below:

StarlingX Kubernetes includes:

Hardened Linux

A CentOS Linux Kernel and OS, tuned for performance and maintained with security CVE patches.

Variety of open-source software supporting StarlingX and/or Kubernetes

Includes packages such as Apache, Ceph, PostgreSql, Etcd, and , as well as some services from OpenStack such as Horizon, Keystone, and Barbican.

StarlingX

Hardware and software infrastructure management. Includes:

• Host Management: Manages installation, maintenance and fault monitoring of dedicated bare metal servers running the StarlingX solution.
• Configuration Management: Manages the configuration of hardware and software services running on the host servers.
• Service Management: Provides the cluster management for services running on the HA control nodes cluster, as well critical software monitoring and recovery of services running on all nodes within the cluster.
• Fault Management: Monitoring and reporting of faults and logs for both hardware and software services.
• Software Management: Support for managing software updates to all layers of software in the solution; this includes kernel, operating system, open-source packages, StarlingX, and Kubernetes.

Kubernetes

Includes:

• Kubernetes Container Orchestration Engine
• Native Docker Runtime
• Calico Container Networking
• Persistent Volume Claims backed by Ceph
• Local Docker Registry
• Helm/Tiller – Kubernetes Package Manager
• FluxCD or Armada Airship (deprecated)

Kubernetes cluster interface

Interfacing with the StarlingX Kubernetes cluster can be done through Kubernetes APIs, kubectl, Helm, or the StarlingX application package manager.

See the Kubernetes APIs for more information.

kubectl

kubectl is available both locally on the controllers/masters or can be installed independently on a remote server for interfacing with the StarlingX Kubernetes cluster and managing both cluster resources and namespace-specific resources. Locally on controllers/masters, admin-level authentication credentials for kubectl can be setup by logging in as sysadmin and running source /etc/platform/openrc.

Remotely, authentication for kubectl uses Kubernetes service account tokens.

See the Kubernetes kubectl documentation for more information.

Helm

StarlingX Kubernetes also supports Helm with Tiller, the Kubernetes package manager that can be used to manage the life cycle of applications within the Kubernetes cluster.

Helm packages are defined by Helm charts with container information sufficient for managing a Kubernetes application. You can configure, install, and upgrade your Kubernetes applications using Helm charts. Helm charts are defined with a default set of values that describe the behavior of the service installed within the Kubernetes cluster.

At system installation, the official curated Helm chart repository is added to the local Helm repository list. In addition, a number of local repositories (containing optional StarlingX packages) are created and added to the Helm repository list.

See the Helm charts repo and Helm documentation for more information.

StarlingX application package manager

Use the StarlingX system application-* commands to manage containerized application deployment from the commandline.

StarlingX application management provides a wrapper around FluxCD and Kubernetes Helm for managing containerized applications. FluxCD is a tool for managing multiple Helm charts with dependencies by centralizing all configurations in a single FluxCD YAML definition and providing life-cycle hooks for all Helm releases.

A StarlingX application package is a compressed tarball containing a metadata.yaml file, a manifest.yaml FluxCD manifest file, and a charts directory containing Helm charts and a checksum.md5 file. The metadata.yaml file contains the application name, version, and optional Helm repository and disabled charts information.

StarlingX application package management provides a set of system CLI commands for managing the life cycle of an application, which includes managing overrides to the Helm charts within the application.

Use the following commands with the StarlingX application manager:

application-list

List all applications.

application-show

Show application details such as name, status, and progress.

application-upload

Upload a new application package. This command loads the application’s FluxCD manifest and Helm charts into an internal database and automatically applies system overrides for well-known Helm charts, allowing the Helm chart to be applied optimally to the current cluster configuration.

helm-override-list

List system Helm charts and the namespaces with Helm chart overrides for each Helm chart.

helm-override-show

Show a Helm chart's overrides for a particular namespace. This command displays system-overrides, user-overrides, and the combined system and user overrides.

helm-override-update

Update Helm chart user-overrides for a particular namespace.

helm-chart-attribute-modify

Enable or disable the installation of a particular Helm chart within an application manifest.

helm-override-delete

Delete a Helm chart’s user-overrides for a particular namespace.

application-apply

Apply or reapply the application manifest and Helm charts. This command installs or updates the existing installation of the application based on its FluxCD manifest, Helm charts, and Helm charts’ combined system and user overrides.

application-abort

Abort the current application operation.

application-update

Update the deployed application to a different version.

application-remove

Uninstall an application.

application-delete

Remove the uninstalled application’s definition from the system, including manifest and Helm charts and Helm chart overrides.