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Add a Python version of our GKE example (pulumi#272)
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joeduffy committed Apr 5, 2019
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1 change: 1 addition & 0 deletions gcp-py-gke/.gitignore
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/bin/
3 changes: 3 additions & 0 deletions gcp-py-gke/Pulumi.yaml
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name: gcp-py-gke
description: A Google Kubernetes Engine (GKE) cluster, with canary deployment
runtime: python
99 changes: 99 additions & 0 deletions gcp-py-gke/README.md
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[![Deploy](https://get.pulumi.com/new/button.svg)](https://app.pulumi.com/new)

# Google Kubernetes Engine (GKE) with a Canary Deployment

This example provisions a [Google Kubernetes Engine (GKE)](https://cloud.google.com/kubernetes-engine/) cluster, using
infrastructure-as-code, and then deploys a Kubernetes Deployment into it, to test that the cluster is working. This
demonstrates that you can manage both the Kubernetes objects themselves, in addition to underlying cloud infrastructure,
using a single configuration language (in this case, Python), tool, and workflow.

# Prerequisites

Ensure you have [Python 3](https://www.python.org/downloads/) and [the Pulumi CLI](https://pulumi.io/install).

We will be deploying to Google Cloud Platform (GCP), so you will need an account. If you don't have an account,
[sign up for free here](https://cloud.google.com/free/). In either case,
[follow the instructions here](https://pulumi.io/quickstart/gcp/setup.html) to connect Pulumi to your GCP account.

This example assumes that you have GCP's `gcloud` CLI on your path. This is installed as part of the
[GCP SDK](https://cloud.google.com/sdk/).

# Running the Example

After cloning this repo, `cd` into it and run these commands. A GKE Kubernetes cluster will appear!

1. Create a new stack, which is an isolated deployment target for this example:

```bash
$ pulumi stack init dev
```

2. Set the required configuration variables for this program:

```bash
$ pulumi config set gcp:project [your-gcp-project-here]
$ pulumi config set gcp:zone us-west1-a # any valid GCP zone here
$ pulumi config set password --secret [your-cluster-password-here]
```

By default, your cluster will have 3 nodes of type `n1-standard-1`. This is configurable, however; for instance
if we'd like to choose 5 nodes of type `n1-standard-2` instead, we can run these commands:

```bash
$ pulumi config set node_count 5
$ pulumi config set node_machine_type n1-standard-2
```

This shows how stacks can be configurable in useful ways. You can even change these after provisioning.

3. Deploy everything with the `pulumi up` command. This provisions all the GCP resources necessary, including
your GKE cluster itself, and then deploys a Kubernetes Deployment running nginx, all in a single gesture:

```bash
$ pulumi up
```

This will show you a preview, ask for confirmation, and then chug away at provisioning your cluster:

```
Updating stack 'gcp-ts-gke-dev'
Performing changes:
Type Name Plan
+ pulumi:pulumi:Stack gcp-py-dev create
+ ├─ gcp:container:Cluster gke-cluster create
+ ├─ pulumi:providers:kubernetes gkeK8s create
+ └─ kubernetes:apps:Deployment canary create
---outputs:---
kubeConfig: "apiVersion: v1\n..."
info: 4 changes updated:
+ 4 resources created
Update duration: 2m07.424737735s
```

After about two minutes, your cluster will be ready, and its config will be printed.

4. From here, you may take this config and use it either in your `~/.kube/config` file, or just by saving it
locally and plugging it into the `KUBECONFIG` envvar. All of your usual `gcloud` commands will work too, of course.

For instance:

```bash
$ pulumi stack output kubeconfig > kubeconfig.yaml
$ KUBECONFIG=./kubeconfig.yaml kubectl get po
NAME READY STATUS RESTARTS AGE
canary-n7wfhtrp-fdbfd897b-lrm58 1/1 Running 0 58s
```

5. At this point, you have a running cluster. Feel free to modify your program, and run `pulumi up` to redeploy changes.
The Pulumi CLI automatically detects what has changed and makes the minimal edits necessary to accomplish these
changes. This could be altering the existing chart, adding new GCP or Kubernetes resources, or anything, really.

6. Once you are done, you can destroy all of the resources, and the stack:

```bash
$ pulumi destroy
$ pulumi stack rm
```
84 changes: 84 additions & 0 deletions gcp-py-gke/__main__.py
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from pulumi import Config, export, get_project, get_stack, Output, ResourceOptions
from pulumi_gcp.config import project, zone
from pulumi_gcp.container import Cluster
from pulumi_kubernetes import Provider
from pulumi_kubernetes.apps.v1 import Deployment

# Read in some configurable settings for our cluster:
config = Config(None)

# nodeCount is the number of cluster nodes to provision. Defaults to 3 if unspecified.
NODE_COUNT = config.get('node_count') or 3
# nodeMachineType is the machine type to use for cluster nodes. Defaults to n1-standard-1 if unspecified.
# See https://cloud.google.com/compute/docs/machine-types for more details on available machine types.
NODE_MACHINE_TYPE = config.get('node_machine_type') or 'n1-standard-1'
# username is the admin username for the cluster.
USERNAME = config.get('username') or 'admin'
# password is the password for the admin user in the cluster.
PASSWORD = config.require('password')

# Now, actually create the GKE cluster.
k8s_cluster = Cluster('gke-cluster',
initial_node_count=NODE_COUNT,
node_version='latest',
min_master_version='latest',
master_auth={ 'username': USERNAME, 'password': PASSWORD },
node_config={
'machine_type': NODE_MACHINE_TYPE,
'oauth_scopes': [
'https://www.googleapis.com/auth/compute',
'https://www.googleapis.com/auth/devstorage.read_only',
'https://www.googleapis.com/auth/logging.write',
'https://www.googleapis.com/auth/monitoring'
],
},
)

# Manufacture a GKE-style Kubeconfig. Note that this is slightly "different" because of the way GKE requires
# gcloud to be in the picture for cluster authentication (rather than using the client cert/key directly).
k8s_info = Output.all(k8s_cluster.name, k8s_cluster.endpoint, k8s_cluster.master_auth)
k8s_config = k8s_info.apply(
lambda info: """apiVersion: v1
clusters:
- cluster:
certificate-authority-data: {0}
server: https://{1}
name: {2}
contexts:
- context:
cluster: {2}
user: {2}
name: {2}
current-context: {2}
kind: Config
preferences: {{}}
users:
- name: {2}
user:
auth-provider:
config:
cmd-args: config config-helper --format=json
cmd-path: gcloud
expiry-key: '{{.credential.token_expiry}}'
token-key: '{{.credential.access_token}}'
name: gcp
""".format(info[2]['clusterCaCertificate'], info[1], '{0}_{1}_{2}'.format(project, zone, info[0])))

# Make a Kubernetes provider instance that uses our cluster from above.
k8s_provider = Provider('gke_k8s', kubeconfig=k8s_config)

# Create a canary deployment to test that this cluster works.
labels = { 'app': 'canary-{0}-{1}'.format(get_project(), get_stack()) }
canary = Deployment('canary',
spec={
'selector': { 'matchLabels': labels },
'replicas': 1,
'template': {
'metadata': { 'labels': labels },
'spec': { 'containers': [{ 'name': 'nginx', 'image': 'nginx' }] },
},
}, __opts__=ResourceOptions(provider=k8s_provider)
)

# Finally, export the kubeconfig so that the client can easily access the cluster.
export('kubeconfig', k8s_config)
3 changes: 3 additions & 0 deletions gcp-py-gke/requirements.txt
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pulumi>=0.17.4
pulumi_gcp>=0.18.2
pulumi_kubernetes>=0.22.0

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