idem-k8s 0.2.0

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The Idem Kubernetes provider

About

An Idem plugin to manage Kubernetes resources.

What is POP?

This project is built with pop, a Python-based implementation of Plugin Oriented Programming (POP). POP seeks to bring together concepts and wisdom from the history of computing in new ways to solve modern computing problems.

For more information:

• Intro to Plugin Oriented Programming (POP)

• pop-awesome

• pop-create

Getting Started

Prerequisites

• Python 3.7+

• git (if installing from source or contributing to the project)

  To contribute to the project and set up your local development environment, see CONTRIBUTING.rst in the source repository for this project.

Installation

You can install idem-k8s with the Python package installer (PyPI) or from source.

Install from PyPI

pip install idem-k8s

Install from source

# Clone repo
git clone git@<your-project-path>/idem-k8s.git
cd idem-k8s

# Set up venv
python3 -m venv .venv
source .venv/bin/activate
pip install -e .

Development

The idem-k8s plugin has built-in automatic code generation to extend support for additional Kubernetes resources. Automatic code generation creates over 90% of the code required to support a new Kubernetes resource.

Automatically generate a Kubernetes resource state file with the following command:

pop-create k8s \
--directory ~/idem_k8s/autogen/dummy \  # directory in which the generated state files are stored
-tv \
-n idem_k8s \
--resource apps/v1/DaemonSet  # resource for which state files are generated

The resource argument follows the format: group/version/kind

For example, to add a resource state for Deployment, the argument is: apps/v1/Deployment

For more information, see the Kubernetes resource objects documentation.

Usage

Setup

After installation, idem-k8s execution and state modules are accessible to the pop hub.

For more information:

• Intro to Plugin Oriented Programming (POP)

• pop hub

To use idem-k8s execution and state modules to manage cluster resources, you need to set up authentication in one of the following ways.

With environment variables

Set KUBE_CONFIG_PATH and KUBE_CTX environment variables to the Kubernetes configuration file and context found in your kube_config file.

In the Idem config file

Edit the Idem config file to include the kube_config_path and context under account extras. Use the following example as a guideline.

acct:
  extras:
    k8s:
      default:
        kube_config_path: ~/.kube/config
        context: default

In a credentials.yaml file

Create or edit an Idem credentials.yaml file to add the kube_config_path and context to a Kubernetes profile. Use the following example as a guideline.

k8s:
  default:
    kube_config_path: ~/.kube/config
    context: default

For more about Idem credentials files, including recommended steps for encryption and environment variables, see Authenticating with Idem

You are now ready to use idem-k8s.

States

Idem SLS files use states to ensure that resources are in a desired configuration. An idem-k8s SLS file supports three state functions: present, absent, and describe.

present

The present function ensures that a resource exists. If a resource doesn’t exist, running present creates it. If the resource already exists, running present might leave it unchanged, or update it if there are any configuration changes.

absent

The absent function ensures that a resource does not exist. If the resource exists, running absent deletes it. If the resource doesn’t exist, running absent has no effect.

describe

The describe function returns a list of all resources in the Kubernetes cluster of the same type as specified in the credential profile.

Accessing States

States can be accessed by their relative location in idem-k8s/k8s/states.

For example, a Kubernetes deployment state can be created with the present function as shown in the following SLS file.

k8s_deployment.sls:

nginx-deployment:
  k8s.apps.v1.deployment.present:
  - metadata:
      name: nginx-deployment
      namespace: default
  - spec:
      replicas: 3
      selector:
        match_labels:
          app: nginx
      strategy:
        rolling_update:
          max_surge: 25%
          max_unavailable: 25%
        type: RollingUpdate
      template:
        metadata:
          labels:
            app: nginx
        spec:
          containers:
          - image: nginx:1.14.20
            image_pull_policy: IfNotPresent
            name: nginx
            ports:
            - container_port: 80
              protocol: TCP
            termination_message_path: /dev/termination-log
            termination_message_policy: File
          restart_policy: Always

The Idem command to create the preceding deployment state is:

idem state $PWD/k8s_deployment.sls

Current Supported Resources

apps.v1

daemon_set

deployment

core.v1

config_map

namespace

secret

service_account

rbac.v1

cluster_role

cluster_role_binding

storage_k8s_io.v1

storage_class