helm/examples/guestbook

Guestbook Example

Guestbook example shows how to bring up the Guestbook Example from Kubernetes using Deployment Manager. It also shows you how to construct and reuse parameterized templates.

Getting started

It is assumed that you have bootstrapped the Deployment Manager on your cluster by following the [README.md][https://github.com/kubernetes/deployment-manager/blob/master/README.md] for bootstrapping the cluster.

Deploying Guestbook

To deploy the Guestbook example, you run the following command.

client --name guestbook --service=http://localhost:8001/api/v1/proxy/namespaces/default/services/manager-service:manager examples/guestbook/guestbook.yaml

Replicated Service

Typical pattern for deploying microservices in Kubernetes is to create both a Replication Controller and a Service. We have created a parameterizable type for that called Replicated Service that we use throughout this example.

The Guestbook example consists of 2 services, a frontend and a Redis service. Frontend is a replicated service with 3 replicas and is created like so:

- name: frontend
  type: https://raw.githubusercontent.com/kubernetes/deployment-manager/master/examples/replicatedservice/replicatedservice.py
  properties:
    service_port: 80
    container_port: 80
    external_service: true
    replicas: 3
    image: gcr.io/google_containers/example-guestbook-php-redis:v3

Redis is a composite type and consists of two replicated services. A master with a single replica and the slaves with 2 replicas. It's construced as follows:

{% set REDIS_PORT = 6379 %}
{% set WORKERS = properties['workers'] or 2 %}

resources:
- name: redis-master
  type: https://raw.githubusercontent.com/kubernetes/deployment-manager/master/examples/replicatedservice/replicatedservice.py
  properties:
    # This has to be overwritten since service names are hard coded in the code
    service_name: redis-master
    service_port: {{ REDIS_PORT }}
    target_port: {{ REDIS_PORT }}
    container_port: {{ REDIS_PORT }}
    replicas: 1
    container_name: master
    image: redis

- name: redis-slave
  type: https://raw.githubusercontent.com/kubernetes/deployment-manager/master/examples/replicatedservice/replicatedservice.py
  properties:
    # This has to be overwritten since service names are hard coded in the code
    service_name: redis-slave
    service_port: {{ REDIS_PORT }}
    container_port: {{ REDIS_PORT }}
    replicas: {{ WORKERS }}
    container_name: worker
    image: kubernetes/redis-slave:v2
    # An example of how to specify env variables.
    env:
    - name: GET_HOSTS_FROM
      value: env
    - name: REDIS_MASTER_SERVICE_HOST
      value: redis-master

Displaying types

You can also (currently using curl, work in progress) see what types have been deployed to the cluster:

curl http://localhost:8001/api/v1/proxy/namespaces/default/services/manager-service:manager/types
["Service","ReplicationController","redis.jinja","https://raw.githubusercontent.com/kubernetes/deployment-manager/master/examples/replicatedservice/replicatedservice.py"]

This shows that there are 2 native types that we have deployed (Service and ReplicationController) and 2 composite types (redis.jinja and one imported from github (replicatedservice.py)).

You can also see where the types are being used by getting details on the particular type:

 curl 'http://localhost:8001/api/v1/proxy/namespaces/default/services/manager-service:manager/types/redis.jinja/instances'
[{"name":"redis","type":"redis.jinja","deployment":"guestbook","manifest":"manifest-1446584669795839153","path":"$.resources[1]"}]

It lists which deployment and manifest as well as JSON path to the type.