Creating an HTTP load-balanced logbook app

This advanced example demonstrates how to build a logbook app that uses node.js for its frontend and MySQL for its backend. The template also creates and connects an HTTP load balancer that load balances across two zones, and an autoscaler to automatically scale the app.

This example assumes you are familiar with Docker containers, as well as Compute Engine resources, particularly HTTP load balancing, autoscaling, managed instance groups, and instance templates.

For more introductory tutorials, refer to the Getting started guide or the Step-by-step guide.

Before you begin

• If you want to use the command-line examples in this guide, install the `gcloud` command-line tool.
• If you want to use the API examples in this guide, set up API access.
• Familiar with Compute Engine HTTP load balancing.
• Familiar with Docker containers.

Creating your templates

This example launches a deployment with several types of resources. To start, you will create reusable templates that define these resources separately. Later on, you will use these templates in your final configuration.

At the end of this example, you will have a deployment that contains these resources:

• A single Compute Engine instance for the backend MySQL virtual machine.
• An instance template that uses a Docker image.
• Two autoscaled managed instance groups in two different zones, running the frontend node.js service.
• Another two autoscaled managed instance group serving static data.
• A health check and a HTTP load balancer to distributed traffic across the respective managed instance groups.

Creating the backend templates

The backend of this app is a single Compute Engine instance running a MySQL Docker container. Create a template that defines a Compute Engine instance that uses a container-optimized image. Name the file container_vm.[py|jinja]:

{% from 'container_helper.jinja' import GenerateManifest %}
{% set COMPUTE_URL_BASE = 'https://www.googleapis.com/compute/v1/' %}
resources:
- name: {{ env['name'] }}
 type: compute.v1.instance
 properties:
 zone: {{ properties['zone'] }}
 machineType: {{ COMPUTE_URL_BASE }}projects/{{ env['project'] }}/zones/{{ properties['zone'] }}/machineTypes/f1-micro
 metadata:
 items:
 - key: gce-container-declaration
 value: |
 {{ GenerateManifest(env['name'], properties['port'], properties['dockerImage'], properties['dockerEnv'])|indent(10) }}
 disks:
 - deviceName: boot
 type: PERSISTENT
 autoDelete: true
 boot: true
 initializeParams:
 diskName: {{ env['name'] }}-disk
 sourceImage: {{ COMPUTE_URL_BASE }}projects/cos-cloud/global/images/{{ properties['containerImage'] }}
 networkInterfaces:
 - accessConfigs:
 - name: external-nat
 type: ONE_TO_ONE_NAT
 network: {{ COMPUTE_URL_BASE }}projects/{{ env['project'] }}/global/networks/default
 serviceAccounts:
 - email: default
 scopes:
 - https://www.googleapis.com/auth/logging.write
 - https://www.googleapis.com/auth/monitoring.write

# Copyright 2016 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Creates a Container VM with the provided Container manifest."""
fromcontainer_helperimport GenerateManifest
COMPUTE_URL_BASE = 'https://www.googleapis.com/compute/v1/'
defGlobalComputeUrl(project, collection, name):
 return ''.join([COMPUTE_URL_BASE, 'projects/', project,
 '/global/', collection, '/', name])
defZonalComputeUrl(project, zone, collection, name):
 return ''.join([COMPUTE_URL_BASE, 'projects/', project,
 '/zones/', zone, '/', collection, '/', name])
defGenerateConfig(context):
"""Generate configuration."""
 base_name = context.env['name']
 # Properties for the container-based instance.
 instance = {
 'zone': context.properties['zone'],
 'machineType': ZonalComputeUrl(context.env['project'],
 context.properties['zone'],
 'machineTypes',
 'f1-micro'),
 'metadata': {
 'items': [{
 'key': 'gce-container-declaration',
 'value': GenerateManifest(context)
 }]
 },
 'disks': [{
 'deviceName': 'boot',
 'type': 'PERSISTENT',
 'autoDelete': True,
 'boot': True,
 'initializeParams': {
 'diskName': base_name + '-disk',
 'sourceImage': GlobalComputeUrl('cos-cloud',
 'images',
 context.properties[
 'containerImage'])
 },
 }],
 'networkInterfaces': [{
 'accessConfigs': [{
 'name': 'external-nat',
 'type': 'ONE_TO_ONE_NAT'
 }],
 'network': GlobalComputeUrl(context.env['project'],
 'networks',
 'default')
 }],
 'serviceAccounts': [{
 'email': 'default',
 'scopes': ['https://www.googleapis.com/auth/logging.write']
 }]
 }
 # Resources to return.
 resources = {
 'resources': [{
 'name': base_name,
 'type': 'compute.v1.instance',
 'properties': instance
 }]
 }
 return resources

The template defines a number of variables, such as the containerImage and the manifest, which will be filled in when you define your configuration. This template alone just creates a single virtual machine (VM) instance.

When you use container images on Compute Engine instances, you also need to provide a manifest file (different from a Deployment Manager manifest) to describe to Compute Engine which container image to use. Create a helper method called container_helper.[py|jinja] to dynamically define the container manifest:

{% macro GenerateManifest(name, port, dockerImage, dockerEnv) -%}

apiVersion: v1
kind: Pod
metadata:
 name: {{ name }}
spec:
 containers:
 - name: {{ name }}
 image: {{ dockerImage }}
 ports:
 - hostPort: {{ port }}
 containerPort: {{ port }}
{% if dockerEnv -%}
 env:
{% for key, value in dockerEnv.items() -%}
 - name: {{ key }}
 value: '{{ value }}'
{% endfor -%}
{% endif -%}
{%- endmacro -%}

# Copyright 2016 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Helper methods for working with containers in config."""
importsix
importyaml
defGenerateManifest(context):
"""Generates a Container Manifest given a Template context.
 Args:
 context: Template context, which must contain dockerImage and port
 properties, and an optional dockerEnv property.
 Returns:
 A Container Manifest as a YAML string.
 """
 env_list = []
 if 'dockerEnv' in context.properties:
 for key, value in six.iteritems(context.properties['dockerEnv']):
 env_list.append({'name': key, 'value': str(value)})
 manifest = {
 'apiVersion': 'v1',
 'kind': 'Pod',
 'metadata': {
 'name': str(context.env['name'])
 },
 'spec': {
 'containers': [{
 'name': str(context.env['name']),
 'image': context.properties['dockerImage'],
 'ports': [{
 'hostPort': context.properties['port'],
 'containerPort': context.properties['port']
 }],
 }]
 }
 }
 if env_list:
 manifest['spec']['containers'][0]['env'] = env_list
 return yaml.dump(manifest, default_flow_style=False)

Creating the frontend templates

The frontend of this app runs Node.js and allow users to post messages to the web page. There will be two managed instance groups that contain two instances each: a primary managed instance group, and a secondary managed instance group for load balancing.

To create these frontend templates, use the following instructions.

1. Create an instance template.

   You need an Instance Template resource to create a managed instance group, which is a group of identical VM instances that are centrally managed. This example creates a managed instance group for the frontend node.js instances, but first, you must create the Instance Template.

   Define a file named container_instance_template.[py|jinja]:

   Jinja

   
   {% from 'container_helper.jinja' import GenerateManifest %}
   {% set IT_NAME = env['name'] + '-it' %}
   resources:
   - name: {{ IT_NAME }}
    type: compute.v1.instanceTemplate
    properties:
    properties:
    metadata:
    items:
    - key: gce-container-declaration
    value: |
    {{ GenerateManifest(env['name'], properties['port'],properties['dockerImage'], properties['dockerEnv'])|indent(12) }}
    machineType: f1-micro
    disks:
    - deviceName: boot
    boot: true
    autoDelete: true
    mode: READ_WRITE
    type: PERSISTENT
    initializeParams:
    sourceImage: https://www.googleapis.com/compute/v1/projects/cos-cloud/global/images/{{ properties['containerImage'] }}
    networkInterfaces:
    - accessConfigs:
    - name: external-nat
    type: ONE_TO_ONE_NAT
    network: https://www.googleapis.com/compute/v1/projects/{{ env['project'] }}/global/networks/default
    serviceAccounts:
    - email: default
    scopes:
    - https://www.googleapis.com/auth/logging.write
    - https://www.googleapis.com/auth/monitoring.write
   outputs:
   - name: instanceTemplateSelfLink
    value: $(ref.{{ IT_NAME }}.selfLink)
   

   Python

   # Copyright 2016 Google Inc. All rights reserved.
   #
   # Licensed under the Apache License, Version 2.0 (the "License");
   # you may not use this file except in compliance with the License.
   # You may obtain a copy of the License at
   #
   # http://www.apache.org/licenses/LICENSE-2.0
   #
   # Unless required by applicable law or agreed to in writing, software
   # distributed under the License is distributed on an "AS IS" BASIS,
   # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   # See the License for the specific language governing permissions and
   # limitations under the License.
   """Creates a Container VM with the provided Container manifest."""
   fromcontainer_helperimport GenerateManifest
   defGenerateConfig(context):
   """Generates configuration."""
    image = ''.join(['https://www.googleapis.com/compute/v1/',
    'projects/cos-cloud/global/images/',
    context.properties['containerImage']])
    default_network = ''.join(['https://www.googleapis.com/compute/v1/projects/',
    context.env['project'],
    '/global/networks/default'])
    instance_template = {
    'name': context.env['name'] + '-it',
    'type': 'compute.v1.instanceTemplate',
    'properties': {
    'properties': {
    'metadata': {
    'items': [{
    'key': 'gce-container-declaration',
    'value': GenerateManifest(context)
    }]
    },
    'machineType': 'f1-micro',
    'disks': [{
    'deviceName': 'boot',
    'boot': True,
    'autoDelete': True,
    'mode': 'READ_WRITE',
    'type': 'PERSISTENT',
    'initializeParams': {'sourceImage': image}
    }],
    'networkInterfaces': [{
    'accessConfigs': [{
    'name': 'external-nat',
    'type': 'ONE_TO_ONE_NAT'
    }],
    'network': default_network
    }],
    'serviceAccounts': [{
    'email': 'default',
    'scopes': ['https://www.googleapis.com/auth/logging.write']
    }]
    }
    }
    }
    outputs = [{'name': 'instanceTemplateSelfLink',
    'value': '$(ref.' + instance_template['name'] + '.selfLink)'}]
    return {'resources': [instance_template], 'outputs': outputs}
   

2. Create an autoscaled managed instance group.

   Now that you have an instance template, you can define a template that uses the instance template to create an autoscaled managed instance group. Create a new file named autoscaled_group.[py|jinja] with the following contents:

   Jinja

   
   resources:
    - name: {{ env["name"] }}-igm
    type: compute.v1.instanceGroupManager
    properties:
    zone: {{ properties["zone"] }}
    targetSize: {{ properties["size"] }}
    baseInstanceName: {{ env["name"] }}-instance
    instanceTemplate: {{ properties["instanceTemplate"] }}
    - name: {{ env["name"] }}-as
    type: compute.v1.autoscaler
    properties:
    zone: {{ properties["zone"] }}
    target: $(ref.{{ env["name"] }}-igm.selfLink)
    autoscalingPolicy:
    maxNumReplicas: {{ properties["maxSize"] }}
   

   Python

   # Copyright 2016 Google Inc. All rights reserved.
   #
   # Licensed under the Apache License, Version 2.0 (the "License");
   # you may not use this file except in compliance with the License.
   # You may obtain a copy of the License at
   #
   # http://www.apache.org/licenses/LICENSE-2.0
   #
   # Unless required by applicable law or agreed to in writing, software
   # distributed under the License is distributed on an "AS IS" BASIS,
   # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   # See the License for the specific language governing permissions and
   # limitations under the License.
   """Creates autoscaled, network LB IGM running specified docker image."""
   defGenerateConfig(context):
   """Generate YAML resource configuration."""
    # NOTE: Once we can specify the port/service during creation of IGM,
    # we will wire it up here.
    name = context.env['name']
    resources = [{
    'name': name + '-igm',
    'type': 'compute.v1.instanceGroupManager',
    'properties': {
    'zone': context.properties['zone'],
    'targetSize': context.properties['size'],
    'baseInstanceName': name + '-instance',
    'instanceTemplate': context.properties['instanceTemplate']
    }
    }, {
    'name': name + '-as',
    'type': 'compute.v1.autoscaler',
    'properties': {
    'zone': context.properties['zone'],
    'target': '$(ref.' + name + '-igm.selfLink)',
    'autoscalingPolicy': {
    'maxNumReplicas': context.properties['maxSize']
    }
    }
    }]
    return {'resources': resources}
   

   Create the corresponding schema file:

   Jinja

   # Copyright 2016 Google Inc. All rights reserved.
   #
   # Licensed under the Apache License, Version 2.0 (the "License");
   # you may not use this file except in compliance with the License.
   # You may obtain a copy of the License at
   #
   # http://www.apache.org/licenses/LICENSE-2.0
   #
   # Unless required by applicable law or agreed to in writing, software
   # distributed under the License is distributed on an "AS IS" BASIS,
   # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   # See the License for the specific language governing permissions and
   # limitations under the License.
   info:
    title: Autoscaled, network LB IGM template
    author: Google
    description: Creates an autoscaled Instance Group Manager running the specified Docker image
    version: 1.0
   required:
   - zone
   - instanceTemplate
   properties:
    zone:
    type: string
    description: Zone in which this VM will run
    instanceTemplate:
    type: string
    description: URL for the instance template to use for IGM
    size:
    type: integer
    default: 1
    description: Initial size of the Managed Instance Group
    maxSize:
    type: integer
    default: 1
    description: Maximum size the Managed Instance Group will be autoscaled to
   

   Python

   # Copyright 2016 Google Inc. All rights reserved.
   #
   # Licensed under the Apache License, Version 2.0 (the "License");
   # you may not use this file except in compliance with the License.
   # You may obtain a copy of the License at
   #
   # http://www.apache.org/licenses/LICENSE-2.0
   #
   # Unless required by applicable law or agreed to in writing, software
   # distributed under the License is distributed on an "AS IS" BASIS,
   # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   # See the License for the specific language governing permissions and
   # limitations under the License.
   info:
    title: Autoscaled, network LB IGM template
    author: Google
    description: Creates an autoscaled Instance Group Manager running the specified Docker image
    version: 1.0
   required:
   - zone
   - instanceTemplate
   properties:
    zone:
    type: string
    description: Zone in which this VM will run
    instanceTemplate:
    type: string
    description: URL for the instance template to use for IGM
    size:
    type: integer
    default: 1
    description: Initial size of the Managed Instance Group
    maxSize:
    type: integer
    default: 1
    description: Maximum size the Managed Instance Group will be autoscaled to
   

3. Create resources using these templates.

   Up to this point, you defined base templates that determine the properties of your resources. Using these templates, define the setup of your frontend. Create a new file named service.[py|jinja] with the following contents:

   Jinja

   
   resources:
    - name: {{ env["name"] }}
    type: container_instance_template.jinja
    properties:
    port: {{ properties["port"] }}
    dockerEnv: {{ properties["dockerEnv"] }}
    dockerImage: {{ properties["dockerImage"] }}
    containerImage: {{ properties["containerImage"] }}
    - name: {{ env["name"] }}-pri
    type: autoscaled_group.jinja
    properties:
    zone: {{ properties["primaryZone"] }}
    size: {{ properties["primarySize"] }}
    maxSize: {{ properties["maxSize"] }}
    port: {{ properties["port"] }}
    service: {{ properties["service"] }}
    baseInstanceName: {{ env["name"] }}-instance
    instanceTemplate: $(ref.{{ env["name"] }}-it.selfLink)
    - name: {{ env["name"] }}-sec
    type: autoscaled_group.jinja
    properties:
    zone: {{ properties["secondaryZone"] }}
    size: {{ properties["secondarySize"] }}
    maxSize: {{ properties["maxSize"] }}
    port: {{ properties["port"] }}
    service: {{ properties["service"] }}
    baseInstanceName: {{ env["name"] }}-instance
    instanceTemplate: $(ref.{{ env["name"] }}-it.selfLink)
    - name: {{ env["name"] }}-hc
    type: compute.v1.httpHealthCheck
    properties:
    port: {{ properties["port"] }}
    requestPath: /_ah/health
    - name: {{ env["name"] }}-bes
    type: compute.v1.backendService
    properties:
    port: {{ properties["port"] }}
    portName: {{ properties["service"] }}
    backends:
    - name: {{ env["name"] }}-primary
    group: $(ref.{{ env["name"] }}-pri-igm.instanceGroup)
    - name: {{ env["name"] }}-secondary
    group: $(ref.{{ env["name"] }}-sec-igm.instanceGroup)
    healthChecks: [ $(ref.{{ env["name"] }}-hc.selfLink) ]
   

   Python

   # Copyright 2016 Google Inc. All rights reserved.
   #
   # Licensed under the Apache License, Version 2.0 (the "License");
   # you may not use this file except in compliance with the License.
   # You may obtain a copy of the License at
   #
   # http://www.apache.org/licenses/LICENSE-2.0
   #
   # Unless required by applicable law or agreed to in writing, software
   # distributed under the License is distributed on an "AS IS" BASIS,
   # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   # See the License for the specific language governing permissions and
   # limitations under the License.
   """Creates primary/secondary zone autoscaled IGM running specified container."""
   defGenerateConfig(context):
   """Generate YAML resource configuration."""
    name = context.env['name']
    resources = [{
    'name': name,
    'type': 'container_instance_template.py',
    'properties': {
    'port': context.properties['port'],
    'dockerEnv': context.properties['dockerEnv'],
    'dockerImage': context.properties['dockerImage'],
    'containerImage': context.properties['containerImage']
    }
    }, {
    'name': name + '-pri',
    'type': 'autoscaled_group.py',
    'properties': {
    'zone': context.properties['primaryZone'],
    'size': context.properties['primarySize'],
    'maxSize': context.properties['maxSize'],
    'port': context.properties['port'],
    'service': context.properties['service'],
    'baseInstanceName': name + '-instance',
    'instanceTemplate': '$(ref.' + name + '-it.selfLink)'
    }
    }, {
    'name': name + '-sec',
    'type': 'autoscaled_group.py',
    'properties': {
    'zone': context.properties['secondaryZone'],
    'size': context.properties['secondarySize'],
    'maxSize': context.properties['maxSize'],
    'port': context.properties['port'],
    'service': context.properties['service'],
    'baseInstanceName': name + '-instance',
    'instanceTemplate': '$(ref.' + name + '-it.selfLink)'
    }
    }, {
    'name': name + '-hc',
    'type': 'compute.v1.httpHealthCheck',
    'properties': {
    'port': context.properties['port'],
    'requestPath': '/_ah/health'
    }
    }, {
    'name': name + '-bes',
    'type': 'compute.v1.backendService',
    'properties': {
    'port': context.properties['port'],
    'portName': context.properties['service'],
    'backends': [{
    'name': name + '-primary',
    'group': '$(ref.' + name + '-pri-igm.instanceGroup)'
    }, {
    'name': name + '-secondary',
    'group': '$(ref.' + name + '-sec-igm.instanceGroup)'
    }],
    'healthChecks': ['$(ref.' + name + '-hc.selfLink)']
    }
    }]
    return {'resources': resources}
   

   Create the corresponding schema file:

   Jinja

   # Copyright 2016 Google Inc. All rights reserved.
   #
   # Licensed under the Apache License, Version 2.0 (the "License");
   # you may not use this file except in compliance with the License.
   # You may obtain a copy of the License at
   #
   # http://www.apache.org/licenses/LICENSE-2.0
   #
   # Unless required by applicable law or agreed to in writing, software
   # distributed under the License is distributed on an "AS IS" BASIS,
   # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   # See the License for the specific language governing permissions and
   # limitations under the License.
   info:
    title: Autoscaled IGM
    author: Google
    description: Creates primary/secondary zone autoscaled IGM running specified container.
    version: 1.0
   imports:
   - path: autoscaled_group.jinja
   - path: ../../common/jinja/container_instance_template.jinja
    name: container_instance_template.jinja
   required:
   - port
   - service
   - primaryZone
   - secondaryZone
   - dockerImage
   properties:
    primarySize:
    type: integer
    default: 1
    description: The size of the primary autoscaled IGM
    secondarySize:
    type: integer
    default: 0
    description: The size of the secondary autoscaled IGM
    maxSize:
    type: integer
    default: 1
    description: The maximum size of the IGM
    containerImage:
    type: string
    default: family/cos-stable
    description: The container image to be used
    dockerEnv:
    type: object
    default: {}
    description: The container environment variables
    dockerImage:
    type: string
    description: the docker image to be used
    port:
    type: integer
    description: Port to expose on the container as well as on the load balancer (e.g., 8080)
    service:
    type: string
    description: Name of the service the port exposes for loadbalancing (backendService) purposes
    primaryZone:
    type: string
    description: Primary Zone in which to run the service
    secondaryZone:
    type: string
    description: Secondary Zone in which to run the service
   

   Python

   # Copyright 2016 Google Inc. All rights reserved.
   #
   # Licensed under the Apache License, Version 2.0 (the "License");
   # you may not use this file except in compliance with the License.
   # You may obtain a copy of the License at
   #
   # http://www.apache.org/licenses/LICENSE-2.0
   #
   # Unless required by applicable law or agreed to in writing, software
   # distributed under the License is distributed on an "AS IS" BASIS,
   # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   # See the License for the specific language governing permissions and
   # limitations under the License.
   info:
    title: Autoscaled IGM
    author: Google
    description: Creates primary/secondary zone autoscaled IGM running specified container.
    version: 1.0
   imports:
   - path: autoscaled_group.py
   - path: ../../common/python/container_instance_template.py
    name: container_instance_template.py
   required:
   - port
   - service
   - primaryZone
   - secondaryZone
   - dockerImage
   properties:
    primarySize:
    type: integer
    default: 1
    description: The size of the primary autoscaled IGM
    secondarySize:
    type: integer
    default: 0
    description: The size of the secondary autoscaled IGM
    maxSize:
    type: integer
    default: 1
    description: The maximum size of the IGM
    containerImage:
    type: string
    default: family/cos-stable
    description: The container image to be used
    dockerEnv:
    type: object
    default: {}
    description: The container environment variables
    dockerImage:
    type: string
    description: the docker image to be used
    port:
    type: integer
    description: Port to expose on the container as well as on the load balancer (e.g., 8080)
    service:
    type: string
    description: Name of the service the port exposes for loadbalancing (backendService) purposes
    primaryZone:
    type: string
    description: Primary Zone in which to run the service
    secondaryZone:
    type: string
    description: Secondary Zone in which to run the service
   

   Let's break down what this template is creating:

   1. Two managed instance groups, one primary and one secondary.

      The template uses the autoscaled_group.[py|jinja] template to create a primary and secondary autoscaled managed instance group.

   2. Next, the template creates a backend service and health checker. A backend service is required for HTTP load balancing, and it defines the serving capacity of the instance groups in that backend service. In this case, the primary and secondary managed instance groups are part of this backend, and the default properties of the backend service apply.

      By default, a backend service performs load balancing based on CPU utilization of the associated instance groups, but you can also load balance based on requests per second (RPS).

      Note: A health check is always required when creating a backend service.

Creating a unifying template

Lastly, create a unifying template that combines both the backend and frontend templates. Create a new file named application.[py|jinja]:

{% set BACKEND = env["deployment"] + "-backend" %}
{% set FRONTEND = env["deployment"] + "-frontend" %}
{% set STATIC_SERVICE = env["deployment"] + "-static-service" %}
{% set APPLICATION = env["deployment"] + "-application" %}
{% set APPLICATION_PORT = 8080 %}
{% set LB_PORT = 8080 %}
{% set MYSQL_PORT = 8080 %}
{% set CONTAINER_IMAGE = "family/cos-stable" %}
resources:
- name: {{ BACKEND }}
 type: container_vm.jinja
 properties:
 zone: {{ properties["primaryZone"] }}
 dockerImage: {{ properties["backendImage"] }}
 containerImage: {{ CONTAINER_IMAGE }}
 port: {{ MYSQL_PORT }}
- name: {{ FRONTEND }}
 type: service.jinja
 properties:
 primaryZone: {{ properties["primaryZone"] }}
 primarySize: 2
 secondaryZone: {{ properties["secondaryZone"] }}
 secondarySize: 0
 dockerImage: {{ properties["frontendImage"] }}
 containerImage: {{ CONTAINER_IMAGE }}
 port: {{ APPLICATION_PORT }}
 service: http
 # If left out will default to 1
 maxSize: 20
 # Define the variables that are exposed to container as env variables.
 dockerEnv:
 SEVEN_SERVICE_MYSQL_PORT: {{ MYSQL_PORT }}
 SEVEN_SERVICE_PROXY_HOST: $(ref.{{ BACKEND }}.networkInterfaces[0].networkIP)
- name: {{ STATIC_SERVICE }}
 type: service.jinja
 properties:
 primaryZone: {{ properties["primaryZone"] }}
 primarySize: 2
 secondaryZone: {{ properties["secondaryZone"] }}
 secondarySize: 0
 dockerImage: {{ properties["staticImage"] }}
 containerImage: {{ CONTAINER_IMAGE }}
 port: {{ APPLICATION_PORT }}
 service: httpstatic
 # If left out will default to 1
 maxSize: 20
- name: {{ APPLICATION }}-urlmap
 type: compute.v1.urlMap
 properties:
 defaultService: $(ref.{{ FRONTEND }}-bes.selfLink)
 hostRules:
 - hosts: ["*"]
 pathMatcher: pathmap
 pathMatchers:
 - name: pathmap
 defaultService: $(ref.{{ FRONTEND }}-bes.selfLink)
 pathRules:
 - paths: ["/static", "/static/*"]
 service: $(ref.{{ STATIC_SERVICE }}-bes.selfLink)
- name: {{ APPLICATION }}-targetproxy
 type: compute.v1.targetHttpProxy
 properties:
 urlMap: $(ref.{{ APPLICATION }}-urlmap.selfLink)
- name: {{ APPLICATION }}-l7lb
 type: compute.v1.globalForwardingRule
 properties:
 IPProtocol: TCP
 portRange: {{ LB_PORT }}
 target: $(ref.{{ APPLICATION }}-targetproxy.selfLink)
- name: {{ APPLICATION }}-fw
 type: compute.v1.firewall
 properties:
 allowed:
 - IPProtocol: TCP
 ports: [ {{ LB_PORT }} ]
 sourceRanges: [ 0.0.0.0/0 ]

# Copyright 2016 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Create appplication template with back-end and front-end templates."""
defGenerateConfig(context):
"""Generate configuration."""
 backend = context.env['deployment'] + '-backend'
 frontend = context.env['deployment'] + '-frontend'
 static_service = context.env['deployment'] + '-static-service'
 application = context.env['deployment'] + '-application'
 container_image = 'family/cos-stable'
 application_port = 8080
 lb_port = 8080
 mysql_port = 8080
 resources = [{
 'name': backend,
 'type': 'container_vm.py',
 'properties': {
 'zone': context.properties['primaryZone'],
 'dockerImage': context.properties['backendImage'],
 'containerImage': container_image,
 'port': mysql_port
 }
 }, {
 'name': frontend,
 'type': 'service.py',
 'properties': {
 'primaryZone': context.properties['primaryZone'],
 'primarySize': 2,
 'secondaryZone': context.properties['secondaryZone'],
 'secondarySize': 0,
 'dockerImage': context.properties['frontendImage'],
 'containerImage': container_image,
 'port': application_port,
 'service': 'http',
 # If left out will default to 1
 'maxSize': 20,
 # Define the variables that are exposed to container as env variables.
 'dockerEnv': {
 'SEVEN_SERVICE_MYSQL_PORT': mysql_port,
 'SEVEN_SERVICE_PROXY_HOST': '$(ref.' + backend
 + '.networkInterfaces[0].networkIP)'
 }
 }
 }, {
 'name': static_service,
 'type': 'service.py',
 'properties': {
 'primaryZone': context.properties['primaryZone'],
 'primarySize': 2,
 'secondaryZone': context.properties['secondaryZone'],
 'secondarySize': 0,
 'dockerImage': context.properties['staticImage'],
 'containerImage': container_image,
 'port': application_port,
 'service': 'httpstatic',
 # If left out will default to 1
 'maxSize': 20
 }
 }, {
 'name': application + '-urlmap',
 'type': 'compute.v1.urlMap',
 'properties': {
 'defaultService': '$(ref.' + frontend + '-bes.selfLink)',
 'hostRules': [{
 'hosts': ['*'],
 'pathMatcher': 'pathmap'
 }],
 'pathMatchers': [{
 'name': 'pathmap',
 'defaultService': '$(ref.' + frontend + '-bes.selfLink)',
 'pathRules': [{
 'paths': ['/static', '/static/*'],
 'service': '$(ref.' + static_service + '-bes.selfLink)'
 }]
 }]
 }
 }, {
 'name': application + '-targetproxy',
 'type': 'compute.v1.targetHttpProxy',
 'properties': {
 'urlMap': '$(ref.' + application + '-urlmap.selfLink)'
 }
 }, {
 'name': application + '-l7lb',
 'type': 'compute.v1.globalForwardingRule',
 'properties': {
 'IPProtocol': 'TCP',
 'portRange': lb_port,
 'target': '$(ref.' + application + '-targetproxy.selfLink)'
 }
 }, {
 'name': application + '-fw',
 'type': 'compute.v1.firewall',
 'properties': {
 'allowed': [{
 'IPProtocol': 'TCP',
 'ports': [lb_port]
 }],
 'sourceRanges': ['0.0.0.0/0']
 }
 }]
 return {'resources': resources}

Create a corresponding schema file:

# Copyright 2016 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
info:
 title: Application Template
 author: Google
 description: Create application template with back-end and front-end templates
 version: 1.0
imports:
- path: service.jinja
- path: ../../common/jinja/container_vm.jinja
 name: container_vm.jinja
required:
- primaryZone
- secondaryZone
- backendImage
- frontendImage
- staticImage
properties:
 primaryZone:
 type: string
 description: Primary Zone in which to run the service
 secondaryZone:
 type: string
 description: Secondary Zone in which to run the service
 backendImage:
 type: string
 description: Docker image to use in the backend
 frontendImage:
 type: string
 description: Docker image to use in the frontend service
 staticImage:
 type: string
 description: Docker image to use in the static service

# Copyright 2016 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
info:
 title: Application Template
 author: Google
 description: Create application template with back-end and front-end templates
 version: 1.0
imports:
- path: service.py
- path: ../../common/python/container_vm.py
 name: container_vm.py
required:
- primaryZone
- secondaryZone
- backendImage
- frontendImage
- staticImage
properties:
 primaryZone:
 type: string
 description: Primary Zone in which to run the service
 secondaryZone:
 type: string
 description: Secondary Zone in which to run the service
 backendImage:
 type: string
 description: Docker image to use in the backend
 frontendImage:
 type: string
 description: Docker image to use in the frontend service
 staticImage:
 type: string
 description: Docker image to use in the static service

In addition to the frontend and backend, the template also defines some additional resources:

1. A static service with primary and secondary managed instance groups. This static service serves a webpage located at the /static path in your app.

2. A URL Map resource. HTTP load balancing requires a URL map to map the different URLs to correct paths. In this case, the default path, indicated by the defaultService property, is the backend service that you created earlier. If a user navigates to /static, the URL map will map that path to the static service, as defined in the pathMatchers section.

3. A global forwarding rule and target HTTP proxy. Since the app is being load balanced across two separate zones, you will need a global forwarding rule that serves a single external IP address. In addition, a target HTTP proxy is required for the HTTP load balancing setup.

4. A firewall rule that allows traffic through port 8080.

Creating your configuration

Now that you have your templates and related schemas ready, you can create a configuration that deploys these resources. Create a configuration file named application.yaml with the following contents, and replace ZONE_TO_RUN and SECONDARY_ZONE_TO_RUN with the primary and secondary zones of your choice.

# Copyright 2016 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# Launches an autoscaled, load-balanced frontend in two zones running nodejs
# for serving traffic using L7 loadbalancing. Also launches a single MySQL
# container instance, wires the two together using references, and passes
# them as env variables to the underlying frontend Docker containers.
#
# NOTE: Due to the fact that IGM does not allow specifying service/port to
# created IG, you must run the following commands after creation of the
# template:
#
# export DEPLOYMENT=<DEPLOYMENT NAME>
# export PRIMARY_ZONE=<PRIMARY ZONE>
# export SECONDARY_ZONE=<SECONDARY ZONE>
#
# gcloud compute instance-groups unmanaged set-named-ports ${DEPLOYMENT}-frontend-pri-igm \
# --named-ports http:8080,httpstatic:8080 \
# --zone ${PRIMARY_ZONE}
#
# gcloud compute instance-groups unmanaged set-named-ports ${DEPLOYMENT}-frontend-sec-igm \
# --named-ports http:8080,httpstatic:8080 \
# --zone ${SECONDARY_ZONE}
#
# Then to see the IP that exposes the application, you can do:
# gcloud compute forwarding-rules list | grep application-${DEPLOYMENT}-l7lb
imports:
-path:application.jinja
resources:
-name:nodejs
type:application.jinja
properties:
primaryZone:ZONE_TO_RUN
secondaryZone:SECOND_ZONE_TO_RUN
backendImage:gcr.io/deployment-manager-examples/mysql
frontendImage:gcr.io/deployment-manager-examples/nodejsservice
staticImage:gcr.io/deployment-manager-examples/nodejsservicestatic

# Copyright 2016 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# Launches an autoscaled, load-balanced frontend in two zones running nodejs
# for serving traffic using L7 loadbalancing. Also launches a single MySQL
# container instance, wires the two together using references, and passes
# them as env variables to the underlying frontend Docker containers.
#
# NOTE: Due to the fact that IGM does not allow specifying service/port to
# created IG, you must run the following commands after creation of the
# template:
#
# export DEPLOYMENT=<DEPLOYMENT NAME>
# export PRIMARY_ZONE=<PRIMARY ZONE>
# export SECONDARY_ZONE=<SECONDARY ZONE>
#
# gcloud compute instance-groups unmanaged set-named-ports ${DEPLOYMENT}-frontend-pri-igm \
# --named-ports http:8080,httpstatic:8080 \
# --zone ${PRIMARY_ZONE}
#
# gcloud compute instance-groups unmanaged set-named-ports ${DEPLOYMENT}-frontend-sec-igm \
# --named-ports http:8080,httpstatic:8080 \
# --zone ${SECONDARY_ZONE}
#
# Then to see the IP that exposes the application, you can do:
# gcloud compute forwarding-rules list | grep application-${DEPLOYMENT}-l7lb
imports:
-path:application.py
resources:
-name:nodejs
type:application.py
properties:
primaryZone:ZONE_TO_RUN
secondaryZone:SECOND_ZONE_TO_RUN
backendImage:gcr.io/deployment-manager-examples/mysql
frontendImage:gcr.io/deployment-manager-examples/nodejsservice
staticImage:gcr.io/deployment-manager-examples/nodejsservicestatic

Deploying your configuration

Now, let's deploy your resources. Using the Google Cloud CLI, run the following command, optionally choosing to replace advanced-configuration-l7 with a deployment name of your choice. Keep in mind that your deployment name will automatically be used to name the resources.

In this example, the deployment name is advanced-configuration-l7. If you opt to change the deployment name, make sure to use that deployment name in all of the following examples.

gcloud deployment-manager deployments create advanced-configuration-l7 --config application.yaml

The response should look similar to the following resources:

Waiting for create operation-1469468950934-5387966d431f0-49b11bc4-1421b2f0...done.
Create operation operation-1469468950934-5387966d431f0-49b11bc4-1421b2f0 completed successfully.
NAME TYPE STATE ERRORS
advanced-configuration-l7-application-fw compute.v1.firewall COMPLETED []
advanced-configuration-l7-application-l7lb compute.v1.globalForwardingRule COMPLETED []
advanced-configuration-l7-application-targetproxy compute.v1.targetHttpProxy COMPLETED []
advanced-configuration-l7-application-urlmap compute.v1.urlMap COMPLETED []
advanced-configuration-l7-backend compute.v1.instance COMPLETED []
advanced-configuration-l7-frontend-bes compute.v1.backendService COMPLETED []
advanced-configuration-l7-frontend-hc compute.v1.httpHealthCheck COMPLETED []
advanced-configuration-l7-frontend-it compute.v1.instanceTemplate COMPLETED []
advanced-configuration-l7-frontend-pri-as compute.v1.autoscaler COMPLETED []
advanced-configuration-l7-frontend-pri-igm compute.v1.instanceGroupManager COMPLETED []
advanced-configuration-l7-frontend-sec-as compute.v1.autoscaler COMPLETED []
advanced-configuration-l7-frontend-sec-igm compute.v1.instanceGroupManager COMPLETED []
advanced-configuration-l7-static-service-bes compute.v1.backendService COMPLETED []
advanced-configuration-l7-static-service-hc compute.v1.httpHealthCheck COMPLETED []
advanced-configuration-l7-static-service-it compute.v1.instanceTemplate COMPLETED []
advanced-configuration-l7-static-service-pri-as compute.v1.autoscaler COMPLETED []
advanced-configuration-l7-static-service-pri-igm compute.v1.instanceGroupManager COMPLETED []
advanced-configuration-l7-static-service-sec-as compute.v1.autoscaler COMPLETED []
advanced-configuration-l7-static-service-sec-igm compute.v1.instanceGroupManager COMPLETED []

Adding service labels

Next, specify the appropriate service labels for your managed instance groups. Service labels are metadata used by the load balancing service to group resources.

To add service labels, run the following commands, matching the primary and secondary zones to the zones you selected in your deployment configuration file:

gcloudcomputeinstance-groupsunmanagedset-named-portsadvanced-configuration-l7-frontend-pri-igm\
--named-ports http:8080,httpstatic:8080 \
--zone [PRIMARY_ZONE]
gcloudcomputeinstance-groupsunmanagedset-named-portsadvanced-configuration-l7-frontend-sec-igm\
--named-ports http:8080,httpstatic:8080 \
--zone [SECONDARY_ZONE]

Testing your configuration

To test your configuration, get the external IP address that is serving traffic by querying the forwarding rule:

gcloud compute forwarding-rules list | grep advanced-configuration-l7-l7lb
advanced-configuration-l7-l7lb 107.178.249.126 TCP advanced-configuration-l7-targetproxy

In this case, the external IP is 107.178.249.126.

In a browser, visit the external IP address at port 8080. For example, if your external IP is 107.178.249.126, the URL would be:

http://107.178.249.126:8080

You should see a blank page, which is expected. Next, post a message to the page. Go to the following URL:

http://107.178.249.126:8080?msg=hello_world!

You will see confirmation that your message was added. Navigate back to the main URL and now the page should have the message:

hello_world!

You can also visit the static page you created, or check the health of your app, by visiting the following URLs:

# Static web page
http://107.178.249.126:8080/static
# Health check
http://107.178.249.126:8080/_ah/health

Congratulations, you've deployed your configuration successfully.

(Optional) Creating Docker images

Docker allows you to automate and run software inside containers. Containers allow you to isolate different services within containers that can all run on a single Linux instance.

This example used some existing Docker images, but you can also create your own versions of these Docker images. You can find the instructions for creating the MySQL backend images and the Node.js frontend images in the Creating your resource templates section.

To create the Docker image that serves the static webpage:

1. Create a new VM instance with a container-optimized image:

   gcloudcomputeinstancescreatedocker-playground\
   --image-familycontainer-vm\
   --image-projectgoogle-containers\
   --zoneus-central1-a\
   --machine-typef1-micro
   

2. Connect to the instance:

   gcloud compute ssh --zone us-central1-a docker-playground
   

3. Create a file named Dockerfile with the following contents:

   FROMnode:latest
   RUNmkdir/var/www/
   ADDservice.js/var/www/service.js
   WORKDIR/var/www/
   RUNnpminstallmysql
   CMD["node","service.js"]
   

4. Create a file named service.js with the following contents:

   varhttp=require('http');
   varurl=require('url');
   console.log('Started static node server')
   http.createServer(function(req,res){
   reqUrl=url.parse(req.url,true);
   res.useChunkedEncodingByDefault=false;
   res.writeHead(200,{'Content-Type':'text/html'});
   if(reqUrl.pathname=='/_ah/health'){
   res.end('ok');
   }elseif(reqUrl.pathname=='/exit'){
   process.exit(-1)
   }else{
   res.end('static server');
   }
   }).listen(8080,'0.0.0.0');
   console.log('Static server running at http://127.0.0.1:8080/');
   

5. Build the Docker image, replacing username with your Docker Hub username. If you do not have a Docker Hub username, create one first before building the Docker image.

   sudo docker build --no-cache -t username/nodejsservicestatic .
   

6. Push the images to the Docker repository:

   sudo docker push username/nodejsservicestatic
   

Now you have the Docker images to run Node.js and MySQL. You can actually see these images on the repository by searching for the image names. To try the images out, you can replace all instances of gcr.io/deployment-manager-examples/mysql and gcr.io/deployment-manager-examples/nodejsservice with your respective images.

Next steps

Once you've completed this sample, you can:

• Continue to build off of this example by creating a more robust webpage, or adding more services to the web server.
• Read more about configurations or deployments.
• Try creating your own configurations.