Deployment configuration for the Airflow scheduler

deployment-scheduler.yaml

kind: Deployment
apiVersion: apps/v1
metadata:
  name: airflow-scheduler
  namespace: airflow-on-k8s
spec:
  replicas: 1
  selector:
    matchLabels:
      tier: airflow
      component: scheduler
      release: airflow-k8s
  template:
    metadata:
      labels:
        tier: airflow
        component: scheduler
        release: airflow-k8s
      annotations:
        cluster-autoscaler.kubernetes.io/safe-to-evict: "true"
    spec:
      restartPolicy: Always
      terminationGracePeriodSeconds: 10
      serviceAccountName: airflow-scheduler-serviceaccount
      initContainers:
        - name: run-airflow-migrations
          image: apache/airflow:1.10.10.1-alpha2-python3.6
          imagePullPolicy: IfNotPresent
          args: ["bash", "-c", "airflow upgradedb || airflow db upgrade"]
          env:          
            - name: AIRFLOW__CORE__FERNET_KEY
              valueFrom:
                secretKeyRef:
                  name: airflow-fernet-key
                  key: fernet-key
            - name: AIRFLOW__CORE__SQL_ALCHEMY_CONN
              valueFrom:
                secretKeyRef:
                  name: airflow-airflow-metadata
                  key: connection
            - name: AIRFLOW_CONN_AIRFLOW_DB
              valueFrom:
                secretKeyRef:
                  name: airflow-airflow-metadata
                  key: connection
          volumeMounts:
            - name: config
              mountPath: "/opt/airflow/airflow.cfg"
              subPath: airflow.cfg
              readOnly: true
      containers:
        - name: scheduler
          image: apache/airflow:1.10.10.1-alpha2-python3.6
          imagePullPolicy: IfNotPresent
          args: ["scheduler"]
          env:          
            - name: AIRFLOW__CORE__FERNET_KEY
              valueFrom:
                secretKeyRef:
                  name: airflow-fernet-key
                  key: fernet-key
            - name: AIRFLOW__CORE__SQL_ALCHEMY_CONN
              valueFrom:
                secretKeyRef:
                  name: airflow-metadata
                  key: connection
            - name: AIRFLOW_CONN_AIRFLOW_DB
              valueFrom:
                secretKeyRef:
                  name: airflow-airflow-metadata
                  key: connection
          livenessProbe:
            failureThreshold: 10
            periodSeconds: 30
            exec:
              command:
              - python
              - -Wignore
              - -c
              - |
                import os
                os.environ['AIRFLOW__CORE__LOGGING_LEVEL'] = 'ERROR'
                os.environ['AIRFLOW__LOGGING__LOGGING_LEVEL'] = 'ERROR'

                from airflow.jobs.scheduler_job import SchedulerJob
                from airflow.utils.net import get_hostname
                import sys

                job = SchedulerJob.most_recent_job()
                sys.exit(0 if job.is_alive() and job.hostname == get_hostname() else 1)
          volumeMounts:
            - name: logs-pv
              mountPath: "/opt/airflow/logs"
            - name: dags-pv
              mountPath: "/opt/airflow/dags"
            - name: config
              mountPath: "/opt/airflow/airflow.cfg"
              subPath: airflow.cfg
              readOnly: true
      volumes:
        - name: config
          configMap:
            name: airflow-config
        - name: dags-pv
          persistentVolumeClaim:
            claimName: dags-pvc
        - name: logs-pv
          persistentVolumeClaim:
            claimName: logs-pvc