Copyright 2018 Google LLC. SPDX-License-Identifier: Apache-2.0

Authors: [email protected], [email protected] [email protected], [email protected]

Building Kubernetes from Source in Minutes

In this repo you'll find instructions for building kubernetes (k8s) from source in minutes.

You will start a GCP VM, install kubernetes (k8s) build and runtime dependencies, then build k8s from source. Afterward, we'll startup the local build and verify its working.

Prerequisites

You must have a Google Cloud Account and gcloud installed and setup locally. You can find instructions on installing gcloud and authenticating with google cloud here.

Starting a GCP VM

$ gcloud compute instances create ${USER}-k8s-build \
--image-family centos-7 \
--image-project centos-cloud \
--machine-type n1-standard-2 \
--boot-disk-size=50GB \
--preemptible 

• -machine-type: n1-standard-2 has 7.5GB RAM and takes about 22m to build k8s, while a n1-standard-8 takes about 11m to build
• --boot-disk-size: default boot disk side (10GB) is insufficient for kubernetes build
• --preemptible (optional)

Full documentation on creating VMs can be found here.

Installing dependencies and cloning k8s repo

$ gcloud compute ssh ${USER}-k8s-build --command="
sudo yum -y update

# install dependencies and docker
sudo yum -y install yum-utils \
net-tools \
device-mapper-persistent-data \
lvm2 

sudo yum-config-manager \
--add-repo \
https://download.docker.com/linux/centos/docker-ce.repo

sudo yum -y install docker-ce

sudo systemctl enable docker
sudo systemctl start docker

# add user, so sudo isn't required for docker commands
sudo usermod -a -G docker ${USER}

# install gcc to build kubernetes
sudo yum -y install gcc

# install git to clone kubernetes
sudo yum -y install git

# cleanup
sudo yum -y clean all

# install golang-11
curl -O https://dl.google.com/go/go1.11.2.linux-amd64.tar.gz
sudo tar -C /usr/local -xzf go1.11.2.linux-amd64.tar.gz
echo 'export PATH=\${PATH}:/usr/local/go/bin' >> ~/.bash_profile
rm -f go1.11.2.linux-amd64.tar.gz

# clone kubernetes 
GOPATH_K8S=\${HOME}/go/src/k8s.io/kubernetes
mkdir -p \${GOPATH_K8S}
git clone https://github.com/kubernetes/kubernetes \${GOPATH_K8S}

# install etcd so that we can run build locally
cd \${GOPATH_K8S}
hack/install-etcd.sh
echo 'export PATH=\${GOPATH_K8S}/third_party/etcd:\${PATH}' >> ~/.bash_profile
"

Building k8s/

Note: this must be run as a separate gcloud compute ssh command as previous command, or logout and login again in order for usermod to take effects.

$ gcloud compute ssh ${USER}-k8s-build --command="
cd \${HOME}/go/src/k8s.io/kubernetes
# build kubernetes
time make quick-release
"

Output snippet

<snip>
+++ [0707 14:02:12] Docker builds done
+++ [0707 14:03:32] Building tarball: final
+++ [0707 14:03:32] Building tarball: test

real	10m47.515s
user	2m39.393s
sys	0m19.103s

On a n1-standard-2 building k8s took 22m, and on a n1-standard-8 building k8s took 11m.

Starting local build of k8s

$ gcloud compute ssh ${USER}-k8s-build --command="
GOPATH_K8S=\${HOME}/go/src/k8s.io/kubernetes
export PATH=\${PATH}:/usr/local/go/bin
export PATH=\${GOPATH_K8S}/third_party/etcd:\${PATH}
cd ${GOPATH_K8S}
# startup local build
hack/local-up-cluster.sh
"

Output snippet

<snip>
Local Kubernetes cluster is running. Press Ctrl-C to shut it down.
<snip>

Verifying local build

To verify that the local build is operational, we'll execute a kubectl command against it.

$ gcloud compute ssh ${USER}-k8s-build --command="
export KUBERNETES_PROVIDER=local
export KUBECONFIG=/var/run/kubernetes/admin.kubeconfig
\${HOME}/go/src/k8s.io/kubernetes/cluster/kubectl.sh get nodes
"

Output snippet

NAME        STATUS    ROLES     AGE       VERSION
127.0.0.1   Ready     <none>    46s       v1.12.0-alpha.0.1948+097f300a4d8dd8

Cleaning up by deleting the compute instance

$ gcloud compute instances delete ${USER}-k8s-build 

Optional: add a unit test in kubernetes source code and run it

We recommend directly ssh to the VM and do the editing.

cd ${HOME}/go/src/k8s.io/kubernetes
emacs -nw pkg/util/normalizer/normalizer_test.go // Add your test for normalizer // Add test target in pkg/util/normalizer/BUILD

To run test

make test WHAT=./pkg/util/normalizer