docker-compose 转换为 kubernetes

Question

i have a docker-compose.yaml

version: '3.4'

services:

  mongodb:
    image: mongo:latest

  assets:
    image: gnaudio/jabra-xpress-assets:v4.0.7020

  frontend:
    image: gnaudio/jabra-xpress-frontend:v4.0.7314
    environment:
    - "ENDPOINT=http://¤HOST-NAME¤:85"
    ports:
    - "80:80"

  backend:
    image: gnaudio/jabra-xpress-api:v4.0.7313
    environment:
    - "ConnectionStrings:XpressDatabaseSqlServer=¤CONNSTRING¤"
    - "ConnectionStrings:MongoDb=mongodb://mongodb/raw"
    - "DefaultAnalyticsEndpoint=http://¤HOST-NAME¤:88/api/v1/Analytics"
    - "JDODownload=http://assets/"
    - "NetworkEndpoint=http://¤HOST-NAME¤:85/api/Xpress/Network/"
    - "SDK:fwURL_base=http://¤HOST-NAME¤:82"
    - "SDK:fsURL_base=http://¤HOST-NAME¤:82"
    ports:
    - "85:80"
    depends_on:
    - mongodb
    - assets
    - sdkbackend

  sdkbackend:
    image: gnaudio/jabra-xpress-sdkbackend:latest
    environment:
    - "Storage:SDKCopyUrl=http://¤HOST-NAME¤:82"
    ports:
    - "82:80"

  analytics:
    image: gnaudio/jabra-xpress-analytics:v4.0.7312
    environment:
    - "ConnectionStrings:MongodbServer=mongodb://mongodb/raw"
    ports:
    - "88:80"
    depends_on:
    - mongodb

  analytics-cron:
    image: gnaudio/jabra-xpress-analytics-cron:v4.0.7313
    environment:
    - "MONGODBCONNECTIONSTRING=mongodb://mongodb/raw"
    depends_on:
    - mongodb

I know I can translate this with kompose up to kubernetes. But what is with the Parts "DefaultAnalyticsEndpoint=http://¤HOST-NAME¤:88/api/v1/Analytics"?

According to the producer of Jabra, you should do that:

Replace ¤CONNSTRING¤ with the SQL connection string Replace ¤HOST-NAME¤ with the server host-name.

What hostname I have to do put in there? I mean I have 6 different Services and Pods. How can they communicate with each other?

Answer 1

As with Docker(-Compose), Kubernetes includes a DNS service that permits you to reference eg Services (Capitalized means the Kubernetes type).

IIRC, Kompose generates Services and Deployments for Docker-Compose services. You will generally refer to Kubernetes services through the Service type and you should have Services for eg frontend , backend etc.

So, in answer to your question, depending on which Service you wish to reference, you will replace ${HOST_NAME} with one of the Service names. It would appear that DefaultAnalyticsEndpoint references the Docker-Compose service analytics . This should be mapped to a Kubernetes Service called analytics too. IIUC, in both case (Docker-Compose and Kubernetes), The HOST-NAME in DefaultAnalyticsEndpoint would be analytics .

If you reference a Service from within the same Namespace, you need only use the Service name eg backend . If you refer to a Service from another Namespace, you will need to include the Namespace specifier, eg backend.${NAMESPACE}.cluster.local

See:

• https://kubernetes.io/docs/concepts/services-networking/connect-applications-service/
• https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/#services