kaniko/docs/tutorial.md at main · GoogleContainerTools/kaniko

Getting Started Tutorial

This tutorial is for beginners who want to start using kaniko and aims to establish a quick start test case.

Table of Content

Prerequisities

A Kubernetes Cluster. You could use Minikube to deploy kubernetes locally, or use kubernetes service from cloud provider like Azure Kubernetes Service.
A dockerhub account to push built image public.

Prepare config files for kaniko

Prepare several config files to create resources in kubernetes, which are:

pod.yaml is for starting a kaniko container to build the example image.
volume.yaml is for creating a persistent volume used as kaniko build context.
volume-claim.yaml is for creating a persistent volume claim which will mounted in the kaniko container.

Prepare the local mounted directory

SSH into the cluster, and create a local directory which will be mounted in kaniko container as build context. Create a simple dockerfile there.

Note: To ssh into cluster, if you use minikube, you could use minikube ssh command. If you use cloud service, please refer to official doc, such as Azure Kubernetes Service.

$ mkdir kaniko && cd kaniko
$ echo 'FROM ubuntu' >> dockerfile
$ echo 'ENTRYPOINT ["/bin/bash", "-c", "echo hello"]' >> dockerfile
$ cat dockerfile
FROM ubuntu
ENTRYPOINT ["/bin/bash", "-c", "echo hello"]
$ pwd
/home/<user-name>/kaniko # copy this path in volume.yaml file

Note: It is important to notice that the hostPath in the volume.yaml need to be replaced with the local directory you created.

Create a Secret that holds your authorization token

A Kubernetes cluster uses the Secret of docker-registry type to authenticate with a docker registry to push an image.

Create this Secret, naming it regcred:

kubectl create secret docker-registry regcred --docker-server=<your-registry-server> --docker-username=<your-name> --docker-password=<your-pword> --docker-email=<your-email>

<your-registry-server> is your Private Docker Registry FQDN. (https://index.docker.io/v1/ for DockerHub)
<your-name> is your Docker username.
<your-pword> is your Docker password.
<your-email> is your Docker email.

This secret will be used in pod.yaml config.

Create resources in kubernetes

# create persistent volume
$ kubectl create -f volume.yaml
persistentvolume/dockerfile created

# create persistent volume claim
$ kubectl create -f volume-claim.yaml
persistentvolumeclaim/dockerfile-claim created

# check whether the volume mounted correctly
$ kubectl get pv dockerfile
NAME         CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                      STORAGECLASS    REASON   AGE
dockerfile   10Gi       RWO            Retain           Bound    default/dockerfile-claim   local-storage            1m

# create pod
$ kubectl create -f pod.yaml
pod/kaniko created
$ kubectl get pods
NAME     READY   STATUS              RESTARTS   AGE
kaniko   0/1     ContainerCreating   0          7s

# check whether the build complete and show the build logs
$ kubectl get pods
NAME     READY   STATUS      RESTARTS   AGE
kaniko   0/1     Completed   0          34s
$ kubectl logs kaniko
➜ kubectl logs kaniko
INFO[0000] Resolved base name ubuntu to ubuntu
INFO[0000] Resolved base name ubuntu to ubuntu
INFO[0000] Downloading base image ubuntu
INFO[0000] Error while retrieving image from cache: getting file info: stat /cache/sha256:1bbdea4846231d91cce6c7ff3907d26fca444fd6b7e3c282b90c7fe4251f9f86: no such file or directory
INFO[0000] Downloading base image ubuntu
INFO[0001] Built cross stage deps: map[]
INFO[0001] Downloading base image ubuntu
INFO[0001] Error while retrieving image from cache: getting file info: stat /cache/sha256:1bbdea4846231d91cce6c7ff3907d26fca444fd6b7e3c282b90c7fe4251f9f86: no such file or directory
INFO[0001] Downloading base image ubuntu
INFO[0001] Skipping unpacking as no commands require it.
INFO[0001] Taking snapshot of full filesystem...
INFO[0001] ENTRYPOINT ["/bin/bash", "-c", "echo hello"]

Note: It is important to notice that the destination in the pod.yaml need to be replaced with your own.

Pull the image and test

If as expected, the kaniko will build image and push to dockerhub successfully. Pull the image to local and run it to test:

$ sudo docker run -it <user-name>/<repo-name>
Unable to find image 'debuggy/helloworld:latest' locally
latest: Pulling from debuggy/helloworld
5667fdb72017: Pull complete
d83811f270d5: Pull complete
ee671aafb583: Pull complete
7fc152dfb3a6: Pull complete
Digest: sha256:2707d17754ea99ce0cf15d84a7282ae746a44ff90928c2064755ee3b35c1057b
Status: Downloaded newer image for debuggy/helloworld:latest
hello

Congratulation! You have gone through the hello world successfully, please refer to project for more details.