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# Orchestrating a source-to-URL deployment on Kubernetes
A Go sample that shows how to use Knative to go from source code in a git
repository to a running application with a URL.
This sample uses the [Build](../../../build/README.md) and [Serving](../../README.md)
components of Knative to orchestrate an end-to-end deployment.
## Prerequisites
You need:
* A Kubernetes cluster with Knative installed. Follow the
[installation instructions](https://github.com/knative/docs/blob/master/install/README.md) if you need
to create one.
* Go installed and configured. This is optional, and only required if you want to run the sample app
locally.
## Configuring Knative
To use this sample, you need to install a build template and register a secret for Docker Hub.
### Install the kaniko build template
This sample leverages the [kaniko build template](https://github.com/knative/build-templates/tree/master/kaniko)
to perform a source-to-container build on your Kubernetes cluster.
Use kubectl to install the kaniko manifest:
```shell
kubectl apply -f https://raw.githubusercontent.com/knative/build-templates/master/kaniko/kaniko.yaml
```
### Register secrets for Docker Hub
In order to push the container that is built from source to Docker Hub, register a secret in
Kubernetes for authentication with Docker Hub.
There are [detailed instructions](https://github.com/knative/docs/blob/master/build/auth.md#basic-authentication-docker)
available, but these are the key steps:
1. Create a new `Secret` manifest, which is used to store your Docker Hub
credentials. Save this file as `docker-secret.yaml`:
```yaml
apiVersion: v1
kind: Secret
metadata:
name: basic-user-pass
annotations:
build.knative.dev/docker-0: https://index.docker.io/v1/
type: kubernetes.io/basic-auth
data:
# Use 'echo -n "username" | base64' to generate this string
username: BASE64_ENCODED_USERNAME
# Use 'echo -n "password" | base64' to generate this string
password: BASE64_ENCODED_PASSWORD
```
1. On Mac or Linux computers, use the following command to generate the base64 encoded
values required for the manifest:
```shell
$ echo -n "username" | base64
dXNlcm5hbWU=
$ echo -n "password" | base64
cGFzc3dvcmQ=
```
1. Create a new `Service Account` manifest which is used to link the build process to the secret.
Save this file as `service-account.yaml`:
```yaml
apiVersion: v1
kind: ServiceAccount
metadata:
name: build-bot
secrets:
- name: basic-user-pass
```
1. After you have created the manifest files, apply them to your cluster with `kubectl`:
```shell
$ kubectl apply -f docker-secret.yaml
secret "basic-user-pass" created
$ kubectl apply -f service-account.yaml
serviceaccount "build-bot" created
```
## Deploying the sample
Now that you've configured your cluster accordingly, you are ready to deploy the
sample service into your cluster.
This sample uses `github.com/mchmarny/simple-app` as a basic Go application, but
you could replace this GitHub repo with your own. The only requirements are that
the repo must contain a `Dockerfile` with the instructions for how to build a
container for the application.
1. You need to create a service manifest which defines the service to deploy, including where
the source code is and which build-template to use. Create a file named
`service.yaml` and copy the following definition. Make sure to replace
`{DOCKER_USERNAME}` with your own Docker Hub username:
```yaml
apiVersion: serving.knative.dev/v1alpha1
kind: Service
metadata:
name: app-from-source
namespace: default
spec:
runLatest:
configuration:
build:
serviceAccountName: build-bot
source:
git:
url: https://github.com/mchmarny/simple-app.git
revision: master
template:
name: kaniko
arguments:
- name: IMAGE
value: &image docker.io/{DOCKER_USERNAME}/app-from-source:latest
revisionTemplate:
spec:
container:
image: *image
imagePullPolicy: Always
env:
- name: SIMPLE_MSG
value: "Hello sample app!"
```
1. Apply this manifest using `kubectl`, and watch the results:
```shell
# Apply the manifest
$ kubectl apply -f service.yaml
service "app-from-source" created
# Watch the pods for build and serving
$ kubectl get pods --watch
NAME READY STATUS RESTARTS AGE
app-from-source-00001-zhddx 0/1 Init:2/3 0 7s
app-from-source-00001-zhddx 0/1 PodInitializing 0 37s
app-from-source-00001-zhddx 0/1 Completed 0 38s
app-from-source-00001-deployment-6d6ff665f9-xfhm5 0/3 Pending 0 0s
app-from-source-00001-deployment-6d6ff665f9-xfhm5 0/3 Pending 0 0s
app-from-source-00001-deployment-6d6ff665f9-xfhm5 0/3 Init:0/1 0 0s
app-from-source-00001-deployment-6d6ff665f9-xfhm5 0/3 Init:0/1 0 2s
app-from-source-00001-deployment-6d6ff665f9-xfhm5 0/3 PodInitializing 0 3s
app-from-source-00001-deployment-6d6ff665f9-xfhm5 2/3 Running 0 6s
app-from-source-00001-deployment-6d6ff665f9-xfhm5 3/3 Running 0 11s
```
1. Once you see the deployment pod switch to the running state, press Ctrl+C to
escape the watch. Your container is now built and deployed!
1. To check on the state of the service, get the service object and examine the
status block:
```shell
$ kubectl get service.serving.knative.dev app-from-source -o yaml
[...]
status:
conditions:
- lastTransitionTime: 2018-07-11T20:50:18Z
status: "True"
type: ConfigurationsReady
- lastTransitionTime: 2018-07-11T20:50:56Z
status: "True"
type: RoutesReady
- lastTransitionTime: 2018-07-11T20:50:56Z
status: "True"
type: Ready
domain: app-from-source.default.example.com
latestCreatedRevisionName: app-from-source-00007
latestReadyRevisionName: app-from-source-00007
observedGeneration: 10
traffic:
- configurationName: app-from-source
percent: 100
revisionName: app-from-source-00007
```
1. After the build has completed and the container is pushed to Docker Hub, you
can deploy the app into your cluster. Ensure that the container image value
in `service.yaml` matches the container you built in
the previous step. Apply the configuration using `kubectl`:
```shell
kubectl apply -f service.yaml
```
1. Now that your service is created, Knative will perform the following steps:
* Fetch the revision specified from GitHub and build it into a container
* Push the container to Docker Hub
* Create a new immutable revision for this version of the app.
* Network programming to create a route, ingress, service, and load balance for your app.
* Automatically scale your pods up and down (including to zero active pods).
1. To get the ingress IP for your cluster, use the following command. If your cluster is new,
it can take some time for the service to get an external IP address:
```shell
$ kubectl get svc knative-ingressgateway -n istio-system
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
knative-ingressgateway LoadBalancer 10.23.247.74 35.203.155.229 80:32380/TCP,443:32390/TCP,32400:32400/TCP 2d
```
1. To find the URL for your service, type:
```shell
$ kubectl get services.serving.knative.dev app-from-source -o=custom-columns=NAME:.metadata.name,DOMAIN:.status.domain
NAME DOMAIN
app-from-source app-from-source.default.example.com
```
1. Now you can make a request to your app to see the result. Replace
`{IP_ADDRESS}` with the address that you got in the previous step:
```shell
curl -H "Host: app-from-source.default.example.com" http://{IP_ADDRESS}
Hello World!
```
## Removing the sample app deployment
To remove the sample app from your cluster, delete the service record:
```shell
kubectl delete -f service.yaml
```
---
Except as otherwise noted, the content of this page is licensed under the
[Creative Commons Attribution 4.0 License](https://creativecommons.org/licenses/by/4.0/),
and code samples are licensed under the
[Apache 2.0 License](https://www.apache.org/licenses/LICENSE-2.0).
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