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reixdRainer 'rei' Schuth
reixd
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Rainer 'rei' Schuth
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[cronjobs] add jitter initcontainer (#135)
Co-authored-by: Rainer 'rei' Schuth <rainer.schuth@digital-results-international.com>
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‎charts/cronjobs/Chart.yaml‎

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name: cronjobs
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description: A generic helm cronjob chart for kubernetes
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type: application
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version: 1.6.6
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version: 1.7.0
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appVersion: latest
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home: https://github.com/klicktipp/helm-charts
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keywords:

‎charts/cronjobs/README.md‎

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# cronjobs
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![Version: 1.6.6](https://img.shields.io/badge/Version-1.6.6-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: latest](https://img.shields.io/badge/AppVersion-latest-informational?style=flat-square)
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![Version: 1.7.0](https://img.shields.io/badge/Version-1.7.0-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: latest](https://img.shields.io/badge/AppVersion-latest-informational?style=flat-square)
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A generic helm cronjob chart for kubernetes
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| secretEnvFrom | list | `[]` | Set secretEnvFrom. |
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| env | object | `{}` | Environment variable entries. |
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| timezone | string | `""` | Default time zone for all CronJobs. Individual jobs can override this value. |
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| startupJitter | object | `{"enabled":false,"image":{"pullPolicy":"IfNotPresent","registry":"docker.io","repository":"bash","tag":"5.3"},"maxSeconds":60,"seed":"cronjobs-jitter"}` | Startup jitter settings for all jobs. Individual jobs can override these values. |
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| startupJitter.enabled | bool | `false` | Enable startup jitter initContainer. |
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| startupJitter.maxSeconds | int | `60` | Maximum startup delay in seconds. The effective delay is between 0 and this value. |
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| startupJitter.seed | string | `"cronjobs-jitter"` | Seed prefix combined with namespace for pseudo-random delay generation. |
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| startupJitter.image | object | `{"pullPolicy":"IfNotPresent","registry":"docker.io","repository":"bash","tag":"5.3"}` | Jitter initContainer image settings. |
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| startupJitter.image.registry | string | `"docker.io"` | Container image registry. |
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| startupJitter.image.repository | string | `"bash"` | Container image repository. |
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| startupJitter.image.tag | string | `"5.3"` | Container image tag. |
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| startupJitter.image.pullPolicy | string | `"IfNotPresent"` | Container image pull policy. |
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| jobs | object | `{}` | Configure jobs. |
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| serviceAccount | object | `{"annotations":{},"automount":true,"create":true,"name":""}` | ServiceAccount configuration. |
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| serviceAccount.create | bool | `true` | Set serviceAccount.create. |

‎charts/cronjobs/templates/_helpers.tpl‎

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{{- end }}
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{{- end }}
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{{/*
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Return the fully qualified startup jitter image reference.
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*/}}
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{{- define "cronjobs.startupJitterImage" -}}
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{{- $repository := .repository | default "bash" -}}
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{{- $tag := .tag | default "5.3" -}}
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{{- if .registry -}}
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{{- printf "%s/%s:%s" .registry $repository $tag -}}
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{{- else -}}
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{{- printf "%s:%s" $repository $tag -}}
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{{- end -}}
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{{- end -}}
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{{/*
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Given a list of strings, concatenate all of them with a dash ("-")
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and slugify the string to be DNS name compatible
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{{- $r := (join "-" .) | lower | replace "." "-" | replace "/" "-" | replace "_" "-" | replace "--" "-" | replace " " "-" | trimPrefix "-" | trunc 63 | trimSuffix "-" }}
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{{- $r }}
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{{- end -}}
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{{/*
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Generate deterministic startup delay seconds from seed parts.
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*/}}
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{{- define "com.klicktipp.generateStartupDelaySeconds" -}}
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{{- $seed := join "-" (index . "seed") -}}
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{{- $exceptionList := list "prod" "staging" -}}
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{{- $hash := sha256sum $seed -}}
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{{- $intFromHash := int64 (printf "%x" (substr 0 8 $hash)) -}}
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{{- $maxSeconds := int (default 60 (index . "maxSeconds")) -}}
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{{- mod $intFromHash (add $maxSeconds 1) -}}
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{{- end -}}

‎charts/cronjobs/templates/cronjob.yaml‎

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{{- $env := mergeOverwrite dict $.Values.env ($job.env | default dict) }}
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{{- $image := mergeOverwrite dict ($.Values.image | default dict) ($job.image | default dict) }}
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{{- $timezone := $job.timezone | default $.Values.timezone }}
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{{- $startupJitter := mergeOverwrite dict ($.Values.startupJitter | default dict) ($job.startupJitter | default dict) }}
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{{- $jitterImage := $startupJitter.image | default dict }}
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{{- $startupJitterSeed := $startupJitter.seed | default "cronjobs-jitter" }}
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{{- $startupJitterMaxSeconds := $startupJitter.maxSeconds | default 60 }}
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{{- $startupDelaySeconds := include "com.klicktipp.generateStartupDelaySeconds" (dict "seed" (list $startupJitterSeed $.Release.Namespace $JOB_NAME_SLUG) "maxSeconds" $startupJitterMaxSeconds) }}
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---
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apiVersion: batch/v1
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kind: CronJob
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{{- end }}
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securityContext:
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{{- toYaml ($job.podSecurityContext | default $.Values.podSecurityContext) | nindent 12 }}
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{{- if $startupJitter.enabled }}
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initContainers:
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- name: jitter
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image: {{ include "cronjobs.startupJitterImage" $jitterImage | quote }}
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imagePullPolicy: {{ $jitterImage.pullPolicy | default "IfNotPresent" }}
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command:
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- /usr/local/bin/bash
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- -ec
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- |
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echo "Startup jitter delay: {{ $startupDelaySeconds }}s"
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sleep {{ $startupDelaySeconds }}
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{{- end }}
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containers:
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- name: {{ .containerName | default ($.Values.commonContainerName | default $JOB_NAME_SLUG) }}
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securityContext:

‎charts/cronjobs/values.yaml‎

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# -- Default time zone for all CronJobs. Individual jobs can override this value.
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timezone: ""
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# -- Startup jitter settings for all jobs. Individual jobs can override these values.
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startupJitter:
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# -- Enable startup jitter initContainer.
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enabled: false
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# -- Maximum startup delay in seconds. The effective delay is between 0 and this value.
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maxSeconds: 60
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# -- Seed prefix combined with namespace for pseudo-random delay generation.
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seed: "cronjobs-jitter"
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# -- Jitter initContainer image settings.
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image:
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# -- Container image registry.
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registry: "docker.io"
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# -- Container image repository.
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repository: bash
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# -- Container image tag.
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tag: "5.3"
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# -- Container image pull policy.
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pullPolicy: IfNotPresent
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# -- Configure jobs.
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jobs: {}
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# test:
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# repository: alpine
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# tag: latest
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# pullPolicy: IfNotPresent
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# startupJitter:
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# enabled: true
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# maxSeconds: 60
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# seed: "my-team"
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# image:
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# registry: "docker.io"
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# repository: bash
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# tag: "5.3"
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# pullPolicy: IfNotPresent
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# # see https://github.com/kubernetes/kubernetes/issues/74848#issuecomment-475178355
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# restartPolicy: Never
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# startingDeadlineSeconds: 60

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