kubernetes - Play 应用程序未从Kubernetes yaml文件中选择环境变量

Question

我的YAML文件定义了以下环境变量。

apiVersion: apps/v1
kind: Deployment
metadata:
  name: codingjediweb
spec:
  replicas: 2
  selector:
    matchLabels:
      app: codingjediweb
  template:
    metadata:
      labels:
        app: codingjediweb
    spec:
      volumes:
      - name: shared-logs
        emptyDir: {}
      containers:
      - name: codingjediweb
        image: docker.io/manuchadha25/codingjediweb:06072020
        volumeMounts:
        - name: shared-logs
          mountPath: /deploy/codingjediweb-1.0/logs/
        env:
            - name: db.cassandraUri
              value: cassandra://xx.yy.zzz.ppp:9042
            - name: db.password
              value: 9__
            - name: db.keyspaceName
              value: dbname
            - name: db.username
              value: dbname2
       ports:
        - containerPort: 9000
      - name: logging
        image: busybox
        volumeMounts:
        - name: shared-logs
          mountPath: /deploy/codingjediweb-1.0/logs/
        command: ['sh', '-c', "while true; do sleep 86400; done"]

我的Play应用程序使用变量。如果未在配置文件中定义变量，则Play会检查环境变量。
https://www.playframework.com/documentation/2.6.x/ConfigFile
我的应用程序选择如下配置:

 val dbUsernameOption = configuration.getOptional[String]("db.username")

    val dbUsername = dbUsernameOption.map(name => name).getOrElse({
      cassandraRepositoryComponentsLogger.error("unable to pick db username from configuration.")
      ""
    })

    val dbPasswordOption = configuration.getOptional[String]("db.password")
    val dbPassword = dbPasswordOption.map(name=>name).getOrElse({
      cassandraRepositoryComponentsLogger.error("unable to pick db password from configuration.")
      ""
    })

当我通过应用Kubernetes YAML文件启动应用程序时，容器停止并且出现错误

unable to pick db username from configuration.
unable to pick db password from configuration.

我可以看到环境变量是在容器中定义的。

# printenv
db.keyspaceName=somename <-- here
KUBERNETES_PORT=tcp://10.15.240.1:443
KUBERNETES_SERVICE_PORT=443
CODINGJEDIWEB_SERVICE_PORT_9000_TCP_ADDR=10.15.249.26
HOSTNAME=codingjediweb-649db4fcb9-xxhwm
CODINGJEDIWEB_SERVICE_PORT_9000_TCP_PORT=9000
SHLVL=1
CODINGJEDIWEB_SERVICE_PORT_9000_TCP_PROTO=tcp
HOME=/root
CODINGJEDIWEB_SERVICE_SERVICE_HOST=10.15.249.26
db.cassandraUri=cassandra://xxx <-- here
CODINGJEDIWEB_SERVICE_PORT_9000_TCP=tcp://10.15.249.26:9000
CODINGJEDIWEB_SERVICE_SERVICE_PORT=9000
CODINGJEDIWEB_SERVICE_PORT=tcp://10.15.249.26:9000
db.username=something <-- here
TERM=xterm
KUBERNETES_PORT_443_TCP_ADDR=10.15.240.1
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
KUBERNETES_PORT_443_TCP_PORT=443
KUBERNETES_PORT_443_TCP_PROTO=tcp
KUBERNETES_SERVICE_PORT_HTTPS=443
KUBERNETES_PORT_443_TCP=tcp://10.15.240.1:443
KUBERNETES_SERVICE_HOST=10.15.240.1
PWD=/
db.password=9__ <-- here
/ #

如果配置文件中缺少配置，Play是否会检查环境变量，这是我不对吗？我不确定这是Play问题还是Kubernetes问题，因为当我在IntelliJ中运行Play应用程序并在构建配置中提供环境变量时，该应用程序便可以工作。

Answer 1

我的猜测是，这些是JVM环境变量和bash / shell环境变量，因此不会被使用。
从K8s Angular 来看，一种选择是将整个配置文件设置为Secret并将其安装在conf/application.conf下

apiVersion: v1
kind: Secret
metadata:
  name: appconf-secret
data:
  application.conf: |
     ...
     ...
     ...

然后:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: codingjediweb
spec:
  replicas: 2
  selector:
    matchLabels:
      app: codingjediweb
  template:
    metadata:
      labels:
        app: codingjediweb
    spec:
      volumes:
      - name: shared-logs
        emptyDir: {}
      - name: appconf
        secret:
          secretName: appconf-secret
      containers:
      - name: codingjediweb
        image: docker.io/manuchadha25/codingjediweb:06072020
        volumeMounts:
        - name: shared-logs
          mountPath: /deploy/codingjediweb-1.0/logs/
        - name: appconf
          mountPath: /deploy/codingjediweb-1.0/conf/application.conf
      ...

另一种方法是使用原始方法，并在Play配置文件中使用 Substitutions。