ready¶

Check if a Kubernetes object exists and is ready.

Usage example¶

In the following example, the ready task checks if a deployment named httpbin-prod exists and its availability condition is set to true, and a service named httpbin exists.

iter8 k launch \
--set "tasks={ready,http}" \
--set ready.deploy=httpbin-prod \
--set ready.service=httpbin \
--set http.url=http://httpbin.default/get \
--set runner=job

Parameters¶

Name	Type	Description
deploy	string	Name of a Kubernetes deployment. The task checks if the deployment exists and its `Available` condition is set to true.
service	string	Name of a Kubernetes service. The task checks if the service exists.
ksvc	string	Name of a Knative service. The task checks if the service exists and its `Ready` condition is set to true.
chaosengine	string	Name of a LitmusChaos ChaosEngine resource object. The task checks if the object exists.
timeout	string	Timeout for readiness check to succeed. Default value is `60s`.
namespace	string	The namespace under which to look for the Kubernetes objects. For experiments that run inside a Kubernetes cluster, the default value of this field is the namespace of the Iter8 experiment; for experiments that run in the local environment, it is the `default` namespace.

Extensions¶

Iter8 can be easily extended to support readiness checks for any type of Kubernetes object (including objects with custom resource types). Please consider submitting a pull request for such extensions. Readiness checking in Iter8 involves two templates, namely, task.ready and k.role. Extending the readiness checks to new resource types involves modifying these templates.

Example¶

Consider the Knative extension for this task; this extension enables Iter8 experiment authors to define readiness check for Knative services. In the following example, the ready task succeed if the Knative service named httpbin exists, and has its Ready condition set to true.

iter8 k launch \
--set "tasks={ready,http}" \
--set ready.ksvc=httpbin \
--set http.url=http://httpbin.default/get \
--set runner=job

The task.ready and k.role were changed in the following ways to create this extension.

task.readyk.role

The group/version/resource (GVR) and the condition that should be checked for a Knative Service are defined in this template.

{{- if .Values.ready.ksvc }}
# task: determine if Knative Service exists and is ready
- task: ready
  with:
    name: {{ .Values.ready.ksvc | quote }}
    group: serving.knative.dev
    version: v1
    resource: services
    condition: Ready
{{- include "task.ready.tn" . }}
{{- end }}

The role named {{ .Release.Name }}-ready is extended with the Knative apiGroup.

{{- if .Values.ready.ksvc }}
- apiGroups: ["serving.knative.dev"]
  resourceNames: [{{ .Values.ready.ksvc | quote }}]
  resources: ["services"]
  verbs: ["get"]
{{- end }}