k8s Certificate Configuration expiration time (default 1 year, modify the source code to solve)

Reference documents: https://blog.51cto.com/11889458/2323328

• Download the source code and switch branch

git clone https://github.com/kubernetes/kubernetes.git -b release-1.17  v1.17.3

• Installation go

mkdir /data/soft
cd /data/soft/
wget https://dl.google.com/go/go1.13.6.linux-amd64.tar.gz
tar zxvf go1.13.6.linux-amd64.tar.gz -C /usr/local/

vim /etc/profile
export GOROOT=/usr/local/go
export GOPATH=/usr/local/gopath
export PATH=$PATH:$GOROOT/bin

source /etc/profile
go version

• Modify the source code

vim /data/v1.17.3/staging/src/k8s.io/client-go/util/cert/cert.go
96         maxAge := time.Hour * 24 * 365 * 10         // one year self-signed certs

vim /data/v1.17.3/cmd/kubeadm/app/constants/constants.go
47         CertificateValidity = time.Hour * 24 * 365 * 10

• Compile

cd /data/v1.17.3/
KUBE_BUILD_PLATFORMS=linux/amd64 make WHAT=cmd/kubeadm GOFLAGS=-v GOGCFLAGS="-N -l"

• Replacement will also compile a binary executable file to a directory of existing systems kubeadm

ls -l /data/v1.17.3/_output/bin/kubeadm
mv /usr/bin/kubeadm /usr/bin/kubeadm_backup
ln -s /data/v1.17.3/_output/bin/kubeadm /usr/bin/kubeadm

• Re-initialize the cluster

kubeadm reset
kubeadm init --config=kubeadm-config.yaml --upload-certs | tee kubeadm-init.log
rm -rf $HOME/.kube
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

• Validation results

cd /etc/kubernetes/pki/
openssl x509 -in front-proxy-client.crt   -noout -text  |grep Not
openssl x509 -in apiserver.crt   -noout -text  |grep Not