rancher-partner-charts/charts/citrix/citrix-cpx-istio-sidecar-in.../create-certs-for-cpx-istio-...

128 lines
3.6 KiB
Bash

#!/bin/bash
set -e
usage() {
cat <<EOF
Generate certificate suitable for use with an Istio webhook service.
This script uses k8s' CertificateSigningRequest API to a generate a
certificate signed by k8s CA suitable for use with Istio webhook
services. This requires permissions to create and approve CSR. See
https://kubernetes.io/docs/tasks/tls/managing-tls-in-a-cluster for
detailed explantion and additional instructions.
The server key/cert k8s CA cert are stored in a k8s secret.
usage: ${0} [OPTIONS]
The following flags are required.
--service Service name of webhook (e.g. cpx-sidecar-injector).
--namespace Namespace where webhook service and secret reside (e.g. citrix-system).
--secret Secret name for CA certificate and server certificate/key pair (e.g. cpx-sidecar-injector-certs).
EOF
exit 1
}
while [[ $# -gt 0 ]]; do
case ${1} in
--service)
service="$2"
shift
;;
--secret)
secret="$2"
shift
;;
--namespace)
namespace="$2"
shift
;;
*)
usage
;;
esac
shift
done
[ -z ${service} ] && service=cpx-sidecar-injector
[ -z ${secret} ] && secret=cpx-sidecar-injector-certs
[ -z ${namespace} ] && namespace=citrix-system
if [ ! -x "$(command -v openssl)" ]; then
echo "openssl not found"
exit 1
fi
csrName=${service}.${namespace}
#tmpdir=$(mktemp -d)
scriptdir="$(dirname "$BASH_SOURCE")"
certdir="$scriptdir/cpx-certs"
mkdir -p ${certdir}
echo "creating certs in directory ${certdir} "
cat <<EOF >> ${certdir}/csr.conf
[req]
req_extensions = v3_req
distinguished_name = req_distinguished_name
[req_distinguished_name]
[ v3_req ]
basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment
extendedKeyUsage = serverAuth
subjectAltName = @alt_names
[alt_names]
DNS.1 = ${service}
DNS.2 = ${service}.${namespace}
DNS.3 = ${service}.${namespace}.svc
EOF
openssl genrsa -out ${certdir}/key.pem 2048
openssl req -new -key ${certdir}/key.pem -subj "/CN=${service}.${namespace}.svc" -out ${certdir}/server.csr -config ${certdir}/csr.conf
# clean-up any previously created CSR for our service. Ignore errors if not present.
kubectl delete csr ${csrName} 2>/dev/null || true
# create server cert/key CSR and send to k8s API
cat <<EOF | kubectl create -f -
apiVersion: certificates.k8s.io/v1beta1
kind: CertificateSigningRequest
metadata:
name: ${csrName}
spec:
groups:
- system:authenticated
request: $(cat ${certdir}/server.csr | base64 | tr -d '\n')
usages:
- digital signature
- key encipherment
- server auth
EOF
# verify CSR has been created
while true; do
kubectl get csr ${csrName}
if [ "$?" -eq 0 ]; then
break
fi
done
# approve and fetch the signed certificate
kubectl certificate approve ${csrName}
# verify certificate has been signed
for x in $(seq 10); do
serverCert=$(kubectl get csr ${csrName} -o jsonpath='{.status.certificate}')
if [[ ${serverCert} != '' ]]; then
break
fi
sleep 1
done
if [[ ${serverCert} == '' ]]; then
echo "ERROR: After approving csr ${csrName}, the signed certificate did not appear on the resource. Giving up after 10 attempts." >&2
exit 1
fi
echo ${serverCert} | openssl base64 -d -A -out ${certdir}/cert.pem
# create the secret with CA cert and server cert/key
kubectl create secret generic ${secret} \
--from-file=key.pem=${certdir}/key.pem \
--from-file=cert.pem=${certdir}/cert.pem \
--dry-run -o yaml |
kubectl -n ${namespace} apply -f -