.. _ansible_collections.kubernetes.core.docsite.k8s_object_template:

*******************
Creating K8S object
*******************

.. contents::
  :local:

Introduction
============

This guide will show you how to utilize Ansible to create Kubernetes objects such as Pods, Deployments, and Secrets.

Scenario Requirements
=====================

* Software

    * Ansible 2.9.17 or later must be installed

    * The Python module ``kubernetes`` must be installed on the Ansible controller (or Target host if not executing against localhost)

    * Kubernetes Cluster

    * Kubectl binary installed on the Ansible controller


* Access / Credentials

    * Kubeconfig configured with the given Kubernetes cluster


Assumptions
===========

- User has required level of authorization to create, delete and update resources on the given Kubernetes cluster.

Caveats
=======

- community.kubernetes 2.0.0 has been renamed to `kubernetes.core <https://github.com/ansible-collections/kubernetes.core>`_

Example Description
===================

In this use case / example, we will create a Pod in the given Kubernetes Cluster.  The following Ansible playbook showcases the basic parameters that are needed for this.

.. code:: yaml

    ---
    - hosts: localhost
      collections:
        - kubernetes.core
      tasks:
        - name: Create a pod
          k8s:
            state: present
            definition:
            apiVersion: v1
            kind: Pod
            metadata:
                name: "utilitypod-1"
                namespace: default
                labels:
                    app: galaxy
            spec:
                containers:
                - name: utilitypod
                  image: busybox

Since Ansible utilizes the Kubernetes API to perform actions, in this use case we will be connecting directly to the Kubernetes cluster.

To begin, there are a few bits of information we will need. Here you are using Kubeconfig which is pre-configured in your machine. The Kubeconfig is generally located at ``~/.kube/config``. It is highly recommended to store sensitive information such as password, user certificates in a more secure fashion using :ref:`ansible-vault` or using `Ansible Tower credentials <https://docs.ansible.com/ansible-tower/latest/html/userguide/credentials.html>`_.

Now you need to supply the information about the Pod which will be created. Using ``definition`` parameter of the ``kubernetes.core.k8s`` module, you specify `PodTemplate <https://kubernetes.io/docs/concepts/workloads/pods/#pod-templates>`_. This PodTemplate is identical to what you provide to the ``kubectl`` command.

What to expect
--------------

- You will see a bit of JSON output after this playbook completes. This output shows various parameters that are returned from the module and from cluster about the newly created Pod.

.. code:: json

    {
        "changed": true,
        "method": "create",
        "result": {
            "apiVersion": "v1",
            "kind": "Pod",
            "metadata": {
                "creationTimestamp": "2020-10-03T15:36:25Z",
                "labels": {
                    "app": "galaxy"
                },
                "name": "utilitypod-1",
                "namespace": "default",
                "resourceVersion": "4511073",
                "selfLink": "/api/v1/namespaces/default/pods/utilitypod-1",
                "uid": "c7dec819-09df-4efd-9d78-67cf010b4f4e"
            },
            "spec": {
                "containers": [{
                    "image": "busybox",
                    "imagePullPolicy": "Always",
                    "name": "utilitypod",
                    "resources": {},
                    "terminationMessagePath": "/dev/termination-log",
                    "terminationMessagePolicy": "File",
                    "volumeMounts": [{
                        "mountPath": "/var/run/secrets/kubernetes.io/serviceaccount",
                        "name": "default-token-6j842",
                        "readOnly": true
                    }]
                }],
                "dnsPolicy": "ClusterFirst",
                "enableServiceLinks": true,
                "priority": 0,
                "restartPolicy": "Always",
                "schedulerName": "default-scheduler",
                "securityContext": {},
                "serviceAccount": "default",
                "serviceAccountName": "default",
                "terminationGracePeriodSeconds": 30,
                "tolerations": [{
                        "effect": "NoExecute",
                        "key": "node.kubernetes.io/not-ready",
                        "operator": "Exists",
                        "tolerationSeconds": 300
                    },
                    {
                        "effect": "NoExecute",
                        "key": "node.kubernetes.io/unreachable",
                        "operator": "Exists",
                        "tolerationSeconds": 300
                    }
                ],
                "volumes": [{
                    "name": "default-token-6j842",
                    "secret": {
                        "defaultMode": 420,
                        "secretName": "default-token-6j842"
                    }
                }]
            },
            "status": {
                "phase": "Pending",
                "qosClass": "BestEffort"
            }
        }
    }

- In the above example, 'changed' is ``True`` which notifies that the Pod creation started on the given cluster. This can take some time depending on your environment.


Troubleshooting
---------------

Things to inspect

- Check if the values provided for username and password are correct
- Check if the Kubeconfig is populated with correct values

.. seealso::

    `Kubernetes Python client <https://github.com/kubernetes-client/python>`_
        The GitHub Page of Kubernetes Python client
    `Kubernetes Python client - Issue Tracker <https://github.com/kubernetes-client/python/issues>`_
        The issue tracker for Kubernetes Python client
    `Kubectl installation <https://kubernetes.io/docs/tasks/tools/install-kubectl/>`_
        Installation guide for installing Kubectl
    :ref:`working_with_playbooks`
        An introduction to playbooks
    :ref:`playbooks_vault`
        Using Vault in playbooks
