k8s Helm CronJob for updating Dynamic DNS Records in Google

googledyndns_cronjob.yml

# Wrote this for updating domains for my homelab cluster
# Uses a simple bash script to get the current IP, then send it to Google Domains

# You could update the env variables to read from a secret, but I use this with a values file
# in this format:
# domains:
#   domainone:
#     domainName: "sub.domain.com"
#     domainUsername: USERNAME
#     domainPassword: PASSWORD
#   domaintwo:
#     domainName: "domaintwo.com"
#     domainUsername: USERNAME
#     domainPassword: PASSWORD

apiVersion: batch/v1
kind: CronJob
metadata:
  name: googledomain-updater
spec:
  schedule: "0 * * * *"
  jobTemplate:
    metadata:
      creationTimestamp: null
    spec:
      ttlSecondsAfterFinished: 100
      template:
        spec:
          volumes:
            - name: googledomain-updater-script
              configMap:
                name: googledomain-updater-script
                defaultMode: 0755
          containers:
          {{- range $key, $val := .Values.domains }}
            - name: updater-{{ $key }}
              image: curlimages/curl:latest
              imagePullPolicy: IfNotPresent
              command: ["sh", "/script.sh"]
              env:
                - name: USERNAME
                  value: {{ required "Missing Username" $val.domainUsername }}
                - name: PASSWORD
                  value: {{ required "Missing Password" $val.domainPassword }}
                - name: HOSTNAME
                  value: {{ required "Missing Domain" $val.domainName }}
              volumeMounts:
                - name: "googledomain-updater-script"
                  mountPath: "/script.sh"
                  subPath: "script.sh"
                  readOnly: true
          {{- end }}
          restartPolicy: Never
---
kind: ConfigMap
apiVersion: v1
metadata:
  name: googledomain-updater-script
data:
  script.sh: |
    IP=$(curl -s "https://domains.google.com/checkip")
    # Update Google DNS Record
    URL="https://${USERNAME}:${PASSWORD}@domains.google.com/nic/update?hostname=${HOSTNAME}&myip=${IP}"
    curl -s $URL