Kubernetes Provider

Overview

Applications started using the Kubernetes provider will result in the application being started inside of a kubernetes environment. This typically means a pod/replication controller/service, etc.. will be created and started.

Unlike Docker, kubernetes supports namespaces. Namespaces allow you to deploy an application into a given namespace and allow for separation from other components started in different namespaces. For an Atomic App deployed in kubernetes, all components of the application will be deployed into the namespace from the configuration in answers.conf.

Configuration

namespace

As mentioned above, kubernetes supports namespaces. The default namespace for an application is set to default unless otherwise specified in the answers.conf. It can be changed in the [general] section of the answers.conf file. An example is below:

[general]
namespace: mynamespace

provider-config

For Kubernetes the configuration file as specified by provider-config is optional. Hosts that have kubernetes set up and running on them may not need a provider-config to be specified because kubernetes services are listening on default ports/addresses. However, if kubernetes was set up to listen on different ports, or you wish to connect to a remote kubernetes environment, then you will need to specify a location for a provider config file.

One example of specifying a provider-config is below:

[general]
provider: kubernetes
provider-config: /home/foo/.kube/config

Configuration Value Defaults

Table 1. Kubernetes default configuration values

Keyword	Required	Description	Default value
namespace	no	namespace to use with each kubectl call	default
provider-config	no	config file that specifies how to connect to kubernetes	none

Operations

atomicapp run

This command deploys the app in Kubernetes cluster in a specified namespace. For the given namespace, the deploy process creates objects (pods, replicas, services) in order as enlisted in Nulecule Kubernetes artifacts.

atomicapp stop

This command undeploys the app in the Kubernetes cluster in a specified namespace. For the given namespace, the undeploy process consist of:

1. Scaling down all replicas to 0

2. Deleting all objects (pods, replicas, services)