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https://github.com/GoogleCloudPlatform/continuous-deployment-on-kubernetes

Get up and running with Jenkins on Google Kubernetes Engine
https://github.com/GoogleCloudPlatform/continuous-deployment-on-kubernetes

continuous-delivery google-cloud kubernetes

Last synced: 2 months ago
JSON representation

Get up and running with Jenkins on Google Kubernetes Engine

Host: GitHub
URL: https://github.com/GoogleCloudPlatform/continuous-deployment-on-kubernetes
Owner: GoogleCloudPlatform
License: apache-2.0
Created: 2015-11-10T00:25:03.000Z (about 9 years ago)
Default Branch: master
Last Pushed: 2024-05-03T04:55:29.000Z (8 months ago)
Last Synced: 2024-10-29T15:28:28.821Z (2 months ago)
Topics: continuous-delivery, google-cloud, kubernetes
Language: Shell
Homepage:
Size: 1.87 MB
Stars: 1,592
Watchers: 151
Forks: 891
Open Issues: 24
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE

Awesome Lists containing this project

awesome-repositories - GoogleCloudPlatform/continuous-deployment-on-kubernetes - Get up and running with Jenkins on Google Kubernetes Engine (Shell)

README

# Lab: Build a Continuous Deployment Pipeline with Jenkins and Kubernetes

For a more in depth best practices guide, go to the solution posted [here](https://cloud.google.com/solutions/jenkins-on-container-engine).

## Introduction

This guide will take you through the steps necessary to continuously deliver
your software to end users by leveraging [Google Container Engine](https://cloud.google.com/container-engine/)
and [Jenkins](https://jenkins.io) to orchestrate the software delivery pipeline.
If you are not familiar with basic Kubernetes concepts, have a look at
[Kubernetes 101](http://kubernetes.io/docs/user-guide/walkthrough/).

In order to accomplish this goal you will use the following Jenkins plugins:
- [Jenkins Kubernetes Plugin](https://wiki.jenkins-ci.org/display/JENKINS/Kubernetes+Plugin) - start Jenkins build executor containers in the Kubernetes cluster when builds are requested, terminate those containers when builds complete, freeing resources up for the rest of the cluster
- [Jenkins Pipelines](https://jenkins.io/solutions/pipeline/) - define our build pipeline declaratively and keep it checked into source code management alongside our application code
- [Google Oauth Plugin](https://wiki.jenkins-ci.org/display/JENKINS/Google+OAuth+Plugin) - allows you to add your google oauth credentials to jenkins

In order to deploy the application with [Kubernetes](http://kubernetes.io/) you will use the following resources:
- [Deployments](http://kubernetes.io/docs/user-guide/deployments/) - replicates our application across our kubernetes nodes and allows us to do a controlled rolling update of our software across the fleet of application instances
- [Services](http://kubernetes.io/docs/user-guide/services/) - load balancing and service discovery for our internal services
- [Ingress](http://kubernetes.io/docs/user-guide/ingress/) - external load balancing and SSL termination for our external service
- [Secrets](http://kubernetes.io/docs/user-guide/secrets/) - secure storage of non public configuration information, SSL certs specifically in our case

## Prerequisites

1. A Google Cloud Platform Account
1. [Enable the Compute Engine, Container Engine, and Container Builder APIs](https://console.cloud.google.com/flows/enableapi?apiid=compute_component,container,cloudbuild.googleapis.com)

## Do this first

In this section you will start your [Google Cloud Shell](https://cloud.google.com/cloud-shell/docs/)
and clone the lab code repository to it.

1. Create a new Google Cloud Platform project: [https://console.developers.google.com/project](https://console.developers.google.com/project)

1. Click the Activate Cloud Shell icon in the top-right and wait for your shell to open.

![](docs/img/cloud-shell.png)

> If you are prompted with a _Learn more_ message, click __Continue__ to
> finish opening the Cloud Shell.

1. When the shell is open, use the [gcloud](https://cloud.google.com/sdk/)
command line interface tool to set your default compute zone:

![](docs/img/cloud-shell-prompt.png)

```shell
gcloud config set compute/zone us-east1-d
```

Output (do not copy):

```output
Updated property [compute/zone].
```

1. Set an environment variable with your project:

```shell
export GOOGLE_CLOUD_PROJECT=$(gcloud config get-value project)
```

Output (do not copy):

```output
Your active configuration is: [cloudshell-...]
```

1. Clone the lab repository in your cloud shell, then `cd` into that dir:

```shell
git clone https://github.com/GoogleCloudPlatform/continuous-deployment-on-kubernetes.git
```

Output (do not copy):

```output
Cloning into 'continuous-deployment-on-kubernetes'...
...
```

```shell
cd continuous-deployment-on-kubernetes
```

## Create a Service Account with permissions

1. Create a service account, on Google Cloud Platform (GCP).

Create a new service account because it's the recommended way to avoid
using extra permissions in Jenkins and the cluster.

```shell
gcloud iam service-accounts create jenkins-sa \
--display-name "jenkins-sa"
```

Output (do not copy):

```output
Created service account [jenkins-sa].
```

1. Add required permissions, to the service account, using predefined roles.

Most of these permissions are related to Jenkins use of _Cloud Build_, and
storing/retrieving build artifacts in _Cloud Storage_. Also, the
service account needs to enable the Jenkins agent to read from a repo
you will create in _Cloud Source Repositories (CSR)_.

```shell
gcloud projects add-iam-policy-binding $GOOGLE_CLOUD_PROJECT \
--member "serviceAccount:jenkins-sa@$GOOGLE_CLOUD_PROJECT.iam.gserviceaccount.com" \
--role "roles/viewer"

gcloud projects add-iam-policy-binding $GOOGLE_CLOUD_PROJECT \
--member "serviceAccount:jenkins-sa@$GOOGLE_CLOUD_PROJECT.iam.gserviceaccount.com" \
--role "roles/source.reader"

gcloud projects add-iam-policy-binding $GOOGLE_CLOUD_PROJECT \
--member "serviceAccount:jenkins-sa@$GOOGLE_CLOUD_PROJECT.iam.gserviceaccount.com" \
--role "roles/storage.admin"

gcloud projects add-iam-policy-binding $GOOGLE_CLOUD_PROJECT \
--member "serviceAccount:jenkins-sa@$GOOGLE_CLOUD_PROJECT.iam.gserviceaccount.com" \
--role "roles/storage.objectAdmin"

gcloud projects add-iam-policy-binding $GOOGLE_CLOUD_PROJECT \
--member "serviceAccount:jenkins-sa@$GOOGLE_CLOUD_PROJECT.iam.gserviceaccount.com" \
--role "roles/cloudbuild.builds.editor"

gcloud projects add-iam-policy-binding $GOOGLE_CLOUD_PROJECT \
--member "serviceAccount:jenkins-sa@$GOOGLE_CLOUD_PROJECT.iam.gserviceaccount.com" \
--role "roles/container.developer"
```

You can check the permissions added using __IAM & admin__ in Cloud Console.

![](docs/img/jenkins_sa_iam.png)

1. Export the service account credentials to a JSON key file in Cloud Shell:

```shell
gcloud iam service-accounts keys create ~/jenkins-sa-key.json \
--iam-account "jenkins-sa@$GOOGLE_CLOUD_PROJECT.iam.gserviceaccount.com"
```

Output (do not copy):

```output
created key [...] of type [json] as [/home/.../jenkins-sa-key.json] for [[email protected]]
```

1. Download the JSON key file to your local machine.

Click __Download File__ from __More__ on the Cloud Shell toolbar:

![](docs/img/download_file.png)

1. Enter the __File path__ as `jenkins-sa-key.json` and click __Download__.

The file will be downloaded to your local machine, for use later.

## Create a Kubernetes Cluster

1. Provision the cluster with `gcloud`:

Use Google Kubernetes Engine (GKE) to create and manage your Kubernetes
cluster, named `jenkins-cd`. Use the _service account_ created earlier.

```shell
gcloud container clusters create jenkins-cd \
--num-nodes 2 \
--machine-type n1-standard-2 \
--cluster-version 1.15 \
--service-account "jenkins-sa@$GOOGLE_CLOUD_PROJECT.iam.gserviceaccount.com"
```

Output (do not copy):

```output
NAME LOCATION MASTER_VERSION MASTER_IP MACHINE_TYPE NODE_VERSION NUM_NODES STATUS
jenkins-cd us-east1-d 1.15.11-gke.15 35.229.29.69 n1-standard-2 1.15.11-gke.15 2 RUNNING
```

1. Once that operation completes, retrieve the credentials for your cluster.

```shell
gcloud container clusters get-credentials jenkins-cd
```

Output (do not copy):

```output
Fetching cluster endpoint and auth data.
kubeconfig entry generated for jenkins-cd.
```

1. Confirm that the cluster is running and `kubectl` is working by listing pods:

```shell
kubectl get pods
```

Output (do not copy):

```output
No resources found.
```

> You would see an error if the cluster was not created, or you did not
> have permissions.

1. Add yourself as a cluster administrator in the cluster's RBAC so that you can
give Jenkins permissions in the cluster:

```shell
kubectl create clusterrolebinding cluster-admin-binding --clusterrole=cluster-admin --user=$(gcloud config get-value account)
```

Output (do not copy):

```output
Your active configuration is: [cloudshell-...]
clusterrolebinding.rbac.authorization.k8s.io/cluster-admin-binding created
```

## Install Helm

In this lab, you will use Helm to install Jenkins with a stable _chart_. Helm
is a package manager that makes it easy to configure and deploy Kubernetes
applications. Once you have Jenkins installed, you'll be able to set up your
CI/CD pipleline.

1. Download and install the helm binary

```shell
wget https://get.helm.sh/helm-v3.2.1-linux-amd64.tar.gz
```

1. Unzip the file to your local system:

```shell
tar zxfv helm-v3.2.1-linux-amd64.tar.gz
cp linux-amd64/helm .
```

1. Add the official stable repository.

```shell
./helm repo add stable https://kubernetes-charts.storage.googleapis.com
```

1. Ensure Helm is properly installed by running the following command. You
should see version `v3.2.1` appear:

```shell
./helm version
```

Output (do not copy):

```output
version.BuildInfo{Version:"v3.2.1", GitCommit:"fe51cd1e31e6a202cba7dead9552a6d418ded79a", GitTreeState:"clean", GoVersion:"go1.13.10"}
```

## Configure and Install Jenkins

You will use a custom [values file](https://github.com/helm/charts/blob/master/stable/jenkins/values.yaml)
to add the GCP specific plugin necessary to use service account credentials to reach your Cloud Source Repository.

1. Use the Helm CLI to deploy the chart with your configuration set.

```shell
./helm install cd-jenkins -f jenkins/values.yaml stable/jenkins --version 1.7.3 --wait
```

Output (do not copy):

```output
...
For more information on running Jenkins on Kubernetes, visit:
https://cloud.google.com/solutions/jenkins-on-container-engine
```

1. The Jenkins pod __STATUS__ should change to `Running` when it's ready:

```shell
kubectl get pods
```

Output (do not copy):

```output
NAME READY STATUS RESTARTS AGE
cd-jenkins-7c786475dd-vbhg4 1/1 Running 0 1m
```

1. Configure the Jenkins service account to be able to deploy to the cluster.

```shell
kubectl create clusterrolebinding jenkins-deploy --clusterrole=cluster-admin --serviceaccount=default:cd-jenkins
```

Output (do not copy):

```output
clusterrolebinding.rbac.authorization.k8s.io/jenkins-deploy created
```

1. Set up port forwarding to the Jenkins UI, from Cloud Shell:

```shell
export JENKINS_POD_NAME=$(kubectl get pods -l "app.kubernetes.io/component=jenkins-master" -o jsonpath="{.items[0].metadata.name}")
kubectl port-forward $JENKINS_POD_NAME 8080:8080 >> /dev/null &
```

1. Now, check that the Jenkins Service was created properly:

```shell
kubectl get svc
```

Output (do not copy):

```output
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
cd-jenkins 10.35.249.67 8080/TCP 3h
cd-jenkins-agent 10.35.248.1 50000/TCP 3h
kubernetes 10.35.240.1 443/TCP 9h
```

This Jenkins configuration is using the [Kubernetes Plugin](https://wiki.jenkins-ci.org/display/JENKINS/Kubernetes+Plugin),
so that builder nodes will be automatically launched as necessary when the
Jenkins master requests them. Upon completion of the work, the builder nodes
will be automatically turned down, and their resources added back to the
cluster's resource pool.

Notice that this service exposes ports `8080` and `50000` for any pods that
match the `selector`. This will expose the Jenkins web UI and builder/agent
registration ports within the Kubernetes cluster. Additionally the `jenkins-ui`
services is exposed using a ClusterIP so that it is not accessible from outside
the cluster.

## Connect to Jenkins

1. The Jenkins chart will automatically create an admin password for you. To
retrieve it, run:

```shell
printf $(kubectl get secret cd-jenkins -o jsonpath="{.data.jenkins-admin-password}" | base64 --decode);echo
```

2. To get to the Jenkins user interface, click on the Web Preview
button![](../docs/img/web-preview.png) in cloud shell, then click
**Preview on port 8080**:

![](docs/img/preview-8080.png)

You should now be able to log in with username `admin` and your auto generated
password.

![](docs/img/jenkins-login.png)

### Your progress, and what's next

You've got a Kubernetes cluster managed by GKE. You've deployed:

* a Jenkins Deployment
* a (non-public) service that exposes Jenkins to its agent containers

You have the tools to build a continuous deployment pipeline. Now you need a
sample app to deploy continuously.

## The sample app

You'll use a very simple sample application - `gceme` - as the basis for your CD
pipeline. `gceme` is written in Go and is located in the `sample-app` directory
in this repo. When you run the `gceme` binary on a GCE instance, it displays the
instance's metadata in a pretty card:

![](docs/img/info_card.png)

The binary supports two modes of operation, designed to mimic a microservice. In
backend mode, `gceme` will listen on a port (8080 by default) and return GCE
instance metadata as JSON, with content-type=application/json. In frontend mode,
`gceme` will query a backend `gceme` service and render that JSON in the UI you
saw above. It looks roughly like this:

```
----------- ------------ ~~~~~~~~~~~~ -----------
| | | | | | | |
| user | ---> | gceme | ---> | lb/proxy | -----> | gceme |
|(browser)| |(frontend)| |(optional)| | |(backend)|
| | | | | | | | |
----------- ------------ ~~~~~~~~~~~~ | -----------
| -----------
| | |
|--> | gceme |
|(backend)|
| |
-----------
```
Both the frontend and backend modes of the application support two additional URLs:

1. `/version` prints the version of the binary (declared as a const in
`main.go`)
1. `/healthz` reports the health of the application. In frontend mode, health
will be OK if the backend is reachable.

### Deploy the sample app to Kubernetes

In this section you will deploy the `gceme` frontend and backend to Kubernetes
using Kubernetes manifest files (included in this repo) that describe the
environment that the `gceme` binary/Docker image will be deployed to. They use a
default `gceme` Docker image that you will be updating with your own in a later
section.

You'll have two primary environments -
[canary](http://martinfowler.com/bliki/CanaryRelease.html) and production - and
use Kubernetes to manage them.

> **Note**: The manifest files for this section of the tutorial are in
> `sample-app/k8s`. You are encouraged to open and read each one before creating
> it per the instructions.

1. First change directories to the sample-app, back in __Cloud Shell__:

```shell
cd sample-app
```

1. Create the namespace for production:

```shell
kubectl create ns production
```

Output (do not copy):

```output
namespace/production created
```

1. Create the production Deployments for frontend and backend:

```shell
kubectl --namespace=production apply -f k8s/production
```

Output (do not copy):

```output
deployment.extensions/gceme-backend-production created
deployment.extensions/gceme-frontend-production created
```

1. Create the canary Deployments for frontend and backend:

```shell
kubectl --namespace=production apply -f k8s/canary
```

Output (do not copy):

```output
deployment.extensions/gceme-backend-canary created
deployment.extensions/gceme-frontend-canary created
```

1. Create the Services for frontend and backend:

```shell
kubectl --namespace=production apply -f k8s/services
```

Output (do not copy):

```output
service/gceme-backend created
service/gceme-frontend created
```

1. Scale the production, frontend service:

```shell
kubectl --namespace=production scale deployment gceme-frontend-production --replicas=4
```

Output (do not copy):

```output
deployment.extensions/gceme-frontend-production scaled
```

1. Retrieve the External IP for the production services:

**This field may take a few minutes to appear as the load balancer is being
provisioned**

```shell
kubectl --namespace=production get service gceme-frontend
```

Output (do not copy):

```output
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
gceme-frontend LoadBalancer 10.35.254.91 35.196.48.78 80:31088/TCP 1m
```

1. Confirm that both services are working by opening the frontend `EXTERNAL-IP`
in your browser

![](docs/img/blue_gceme.png)

1. Poll the production endpoint's `/version` URL.

Open a new **Cloud Shell** terminal by clicking the `+` button to the right
of the current terminal's tab.

```shell
export FRONTEND_SERVICE_IP=$(kubectl get -o jsonpath="{.status.loadBalancer.ingress[0].ip}" --namespace=production services gceme-frontend)
while true; do curl http://$FRONTEND_SERVICE_IP/version; sleep 3; done
```

Output (do not copy):

```output
1.0.0
1.0.0
1.0.0
```

You should see that all requests are serviced by v1.0.0 of the application.

Leave this running in the second terminal so you can easily observe rolling
updates in the next section.

1. Return to the first terminal/tab in Cloud Shell.

### Create a repository for the sample app source

Here you'll create your own copy of the `gceme` sample app in
[Cloud Source Repository](https://cloud.google.com/source-repositories/docs/).

1. Initialize the git repository.

Make sure to work from the `sample-app` directory of the repo you cloned previously.

```shell
git init
git config credential.helper gcloud.sh
gcloud source repos create gceme
```

1. Add a _git remote_ for the new repo in Cloud Source Repositories.

```shell
git remote add origin https://source.developers.google.com/p/$GOOGLE_CLOUD_PROJECT/r/gceme
```

1. Ensure git is able to identify you:

```shell
git config --global user.email "YOUR-EMAIL-ADDRESS"
git config --global user.name "YOUR-NAME"
```

1. Add, commit, and push all the files:

```shell
git add .
git commit -m "Initial commit"
git push origin master
```

Output (do not copy):

```output
To https://source.developers.google.com/p/myproject/r/gceme
* [new branch] master -> master
```

## Create a pipeline

You'll now use __Jenkins__ to define and run a pipeline that will test, build,
and deploy your copy of `gceme` to your Kubernetes cluster. You'll approach this
in phases. Let's get started with the first.

### Phase 1: Add your service account credentials

First, you will need to configure GCP credentials in order for Jenkins to be
able to access the code repository:

1. In the **Jenkins UI**, Click **Credentials** on the left
1. Click the **(global)** link
1. Click **Add Credentials** on the left
1. From the **Kind** dropdown, select `Google Service Account from private key`
1. Enter the **Project Name** from your project
1. Leave **JSON key** selected, and click **Choose File**.
1. Select the `jenkins-sa-key.json` file downloaded earlier, then click
**Open**.

![](docs/img/jenkins_creds_safromkey.png)

1. Click **OK**

You should now see 1 global credential. Make a note of the name of the
credential, as you will reference this in Phase 2.

![](docs/img/jenkins-credentials.png)

### Phase 2: Create a job

This lab uses [Jenkins Pipeline](https://jenkins.io/solutions/pipeline/) to
define builds as _groovy_ scripts.

Navigate to your Jenkins UI and follow these steps to configure a Pipeline job
(hot tip: you can find the IP address of your Jenkins install with `kubectl get
ingress --namespace jenkins`):

1. Click the **Jenkins** link in the top left toolbar, of the ui

1. Click the **New Item** link in the left nav

1. For **item name** use `sample-app`, choose the **Multibranch Pipeline**
option, then click **OK**

![](docs/img/sample-app.png)

1. Click **Add source** and choose **git**

1. Paste the **HTTPS clone URL** of your `gceme` repo on Cloud Source
Repositories into the **Project Repository** field.
It will look like:
https://source.developers.google.com/p/[REPLACE_WITH_YOUR_PROJECT_ID]/r/gceme

1. From the **Credentials** dropdown, select the name of the credential from
Phase 1. It should have the format `PROJECT_ID service account`.

1. Under **Scan Multibranch Pipeline Triggers** section, check the
**Periodically if not otherwise run** box, then set the **Interval** value to
`1 minute`.

![](docs/img/git-credentials.png)

1. Click **Save**, leaving all other options with default values.

A _Branch indexing_ job was kicked off to identify any branches in your
repository.

1. Click **Jenkins** > **sample-app**, in the top menu.

You should see the `master` branch now has a job created for it.

The first run of the job will fail, until the _project name_ is set properly
in the `Jenkinsfile` next step.

![](docs/img/first-build.png)

### Phase 3: Modify Jenkinsfile, then build and test the app

1. Create a branch for the canary environment called `canary`

```shell
git checkout -b canary
```

Output (do not copy):

```output
Switched to a new branch 'canary'
```

The [`Jenkinsfile`](https://jenkins.io/doc/book/pipeline/jenkinsfile/) is
written using the Jenkins Workflow DSL, which is Groovy-based. It allows an
entire build pipeline to be expressed in a single script that lives alongside
your source code and supports powerful features like parallelization, stages,
and user input.

1. Update your `Jenkinsfile` script with the correct **PROJECT** environment value.

**Be sure to replace `REPLACE_WITH_YOUR_PROJECT_ID` with your project name.**

Save your changes, but don't commit the new `Jenkinsfile` change just yet.
You'll make one more change in the next section, then commit and push them
together.

### Phase 4: Deploy a [canary release](http://martinfowler.com/bliki/CanaryRelease.html) to canary

Now that your pipeline is working, it's time to make a change to the `gceme` app
and let your pipeline test, package, and deploy it.

The canary environment is rolled out as a percentage of the pods behind the
production load balancer. In this case we have 1 out of 5 of our frontends
running the canary code and the other 4 running the production code. This allows
you to ensure that the canary code is not negatively affecting users before
rolling out to your full fleet. You can use the
[labels](http://kubernetes.io/docs/user-guide/labels/) `env: production` and
`env: canary` in Google Cloud Monitoring in order to monitor the performance of
each version individually.

1. In the `sample-app` repository on your workstation open `html.go` and replace
the word `blue` with `orange` (there should be exactly two occurrences):

```html
//snip

Backend that serviced this request

//snip
```

1. In the same repository, open `main.go` and change the version number from
`1.0.0` to `2.0.0`:

```go
//snip
const version string = "2.0.0"
//snip
```

1. Push the _version 2_ changes to the repo:

```shell
git add Jenkinsfile html.go main.go
```

```shell
git commit -m "Version 2"
```

```shell
git push origin canary
```

1. Revisit your sample-app in the Jenkins UI.

Navigate back to your Jenkins `sample-app` job. Notice a canary pipeline
job has been created.

![](docs/img/sample_app_master_canary.png)

1. Follow the canary build output.

* Click the **Canary** link.
* Click the **#1** link the **Build History** box, on the lower left.
* Click **Console Output** from the left-side menu.
* Scroll down to follow.

1. Track the output for a few minutes.

When you see `Finished: SUCCESS`, open the Cloud Shell terminal that you
left polling `/version` of _canary_. Observe that some requests are now
handled by the _canary_ `2.0.0` version.

```
1.0.0
1.0.0
1.0.0
1.0.0
2.0.0
2.0.0
1.0.0
1.0.0
1.0.0
1.0.0
```

You have now rolled out that change, version 2.0.0, to a **subset** of users.

1. Continue the rollout, to the rest of your users.

Back in the other Cloud Shell terminal, create a branch called
`production`, then push it to the Git server.

```shell
git checkout master
git merge canary
git push origin master
```

1. Watch the pipelines in the Jenkins UI handle the change.

Within a minute or so, you should see a new job in the **Build Queue** and **Build Executor**.

![](docs/img/master_build_executor.png)

1. Clicking on the `master` link will show you the stages of your pipeline as
well as pass/fail and timing characteristics.

You can see the failed master job #1, and the successful master job #2.

![](docs/img/master_two_pipeline.png)

1. Check the Cloud Shell terminal responses again.

In Cloud Shell, open the terminal polling canary's `/version` URL and observe
that the new version, `2.0.0`, has been rolled out and is serving all
requests.

```
2.0.0
2.0.0
2.0.0
2.0.0
2.0.0
2.0.0
2.0.0
2.0.0
2.0.0
2.0.0
```

If you want to understand the pipeline stages in greater detail, you can
look through the `Jenkinsfile` in the `sample-app` project directory.

### Phase 5: Deploy a development branch

Oftentimes changes will not be so trivial that they can be pushed directly to
the **canary** environment. In order to create a **development** environment,
from a long lived feature branch, all you need to do is push it up to the Git
server. Jenkins will automatically deploy your **development** environment.

In this case you will not use a loadbalancer, so you'll have to access your
application using `kubectl proxy`. This proxy authenticates itself with the
Kubernetes API and proxies requests from your local machine to the service in
the cluster without exposing your service to the internet.

#### Deploy the development branch

1. Create another branch and push it up to the Git server

```shell
git checkout -b new-feature
git push origin new-feature
```

1. Open Jenkins in your web browser and navigate back to sample-app.

You should see that a new job called `new-feature` has been created,
and this job is creating your new environment.

![](docs/img/new_feature_job.png)

1. Navigate to the console output of the first build of this new job by:

* Click the **new-feature** link in the job list.
* Click the **#1** link in the Build History list on the left of the page.
* Finally click the **Console Output** link in the left menu.

1. Scroll to the bottom of the console output of the job to see
instructions for accessing your environment:

```
Successfully verified extensions/v1beta1/Deployment: gceme-frontend-dev
AvailableReplicas = 1, MinimumReplicas = 1

[Pipeline] echo
To access your environment run `kubectl proxy`
[Pipeline] echo
Then access your service via
http://localhost:8001/api/v1/proxy/namespaces/new-feature/services/gceme-frontend:80/
[Pipeline] }
```

#### Access the development branch

1. Set up port forwarding to the dev frontend, from Cloud Shell:

```shell
export DEV_POD_NAME=$(kubectl get pods -n new-feature -l "app=gceme,env=dev,role=frontend" -o jsonpath="{.items[0].metadata.name}")
kubectl port-forward -n new-feature $DEV_POD_NAME 8001:80 >> /dev/null &
```

1. Access your application via localhost:

```shell
curl http://localhost:8001/api/v1/proxy/namespaces/new-feature/services/gceme-frontend:80/
```

Output (do not copy):

```output

...

```

Look through the response output for `"card orange"` that was changed earlier.

1. You can now push code changes to the `new-feature` branch in order to update
your development environment.

1. Once you are done, merge your `new-feature ` branch back into the `canary`
branch to deploy that code to the canary environment:

```shell
git checkout canary
git merge new-feature
git push origin canary
```

1. When you are confident that your code won't wreak havoc in production, merge
from the `canary` branch to the `master` branch. Your code will be
automatically rolled out in the production environment:

```shell
git checkout master
git merge canary
git push origin master
```

1. When you are done with your development branch, delete it from Cloud
Source Repositories, then delete the environment in Kubernetes:

```shell
git push origin :new-feature
kubectl delete ns new-feature
```

## Extra credit: deploy a breaking change, then roll back

Make a breaking change to the `gceme` source, push it, and deploy it through the
pipeline to production. Then pretend latency spiked after the deployment and you
want to roll back. Do it! Faster!

Things to consider:

* What is the Docker image you want to deploy for roll back?
* How can you interact directly with the Kubernetes to trigger the deployment?
* Is SRE really what you want to do with your life?

## Clean up

Clean up is really easy, but also super important: if you don't follow these
instructions, you will continue to be billed for the GKE cluster you created.

To clean up, navigate to the
[Google Developers Console Project List](https://console.developers.google.com/project),
choose the project you created for this lab, and delete it. That's it.