OpenSSL Alpine

Docker image based on Alpine Linux that uses OpenSSL to generate a three tier x509 certificate chain.

x509 is a standard for a public key infrastructure (PKI) to manage digital certificates, public-key encryption and a key part of the Transport Layer Security (TLS) protocol used to secure web and email communication.

Customisation

The image comes with default values, but they can be overridden using the following environment variables when running a docker container to customise the generated certificates:

VARIABLE	DESCRIPTION	DEFAULT
COUNTRY	Certificate subject country string	UK
STATE	Certificate subject state string	Greater London
LOCATION	Certificate subject location string	London
ORGANISATION	Certificate subject organisation string	Example
ROOT_CN	Root certificate common name	Root
ISSUER_CN	Intermediate issuer certificate common name	Example Ltd
PUBLIC_CN	Public certificate common name	*.example.com
ROOT_NAME	Root certificate filename	root
ISSUER_NAME	Intermediate issuer certificate filename	example
PUBLIC_NAME	Public certificate filename	public
RSA_KEY_NUMBITS	The size of the rsa keys to generate in bits	2048
DAYS	The number of days to certify the certificates for	365
KEYSTORE_NAME	Keystore filename	keystore
KEYSTORE_PASS	Keystore password	changeit

For example, to run a container, customise variables and mount the certificates in a volume:

docker run --rm \
-e COUNTRY="ME" \
-e STATE="Middle Earth" \
-e LOCATION="The Shire" \
-e ORGANISATION="Hobbit" \
-e ISSUER_CN="J R R Tolkien" \
-e PUBLIC_CN="hobbit.com" \
-e ISSUER_NAME="tolkien" \
-e PUBLIC_NAME="hobbit" \
-v hobbit:/etc/ssl/certs \
pgarrett/openssl-alpine

List the generated certificates:

ls -la /var/lib/docker/volumes/hobbit/_data

View the public certificate details:

openssl x509 -in /var/lib/docker/volumes/hobbit/_data/hobbit.crt -text -noout