Keycloak SSL setup using docker image

I also faced the issue of getting an ERR_SSL_VERSION_OR_CIPHER_MISMATCH error, using the jboss/keycloak Docker image and free certificates from letsencrypt. Even after considering the advices from the other comments. Now, I have a working (and quite easy) setup, which might also help you.

1) Generate letsencrypt certificate

At first, I generated my letsencrypt certificate for domain sub.example.com using the certbot. You can find detailed instructions and alternative ways to gain a certificate at https://certbot.eff.org/ and the user guide at https://certbot.eff.org/docs/using.html.

$ sudo certbot certonly --standalone
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator standalone, Installer None
Please enter in your domain name(s) (comma and/or space separated)  (Enter 'c' to cancel): sub.example.com
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for sub.example.com
Waiting for verification...
Cleaning up challenges

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/sub.example.com/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/sub.example.com/privkey.pem
   Your cert will expire on 2020-01-27. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot
   again. To non-interactively renew *all* of your certificates, run
   "certbot renew"

2) Prepare docker-compose environment

I use docker-compose to run keycloak via docker. The config and data files are stored in path /srv/docker/keycloak/.

• Folder config contains the docker-compose.yml
• Folder data/certs contains the certificates I generated via letsencrypt
• Folder data/keycloack_db is mapped to the database container to make its data persistent.

Put the certificate files to the right path

When I first had issues using the original letscrypt certificates for keycloak, I tried the workaround of converting the certificates to another format, as mentioned in the comments of the former answers, which also failed. Eventually, I realized that my problem was caused by permissions set to the mapped certificate files.

So, what worked for me is to just to copy and rename the files provided by letsencrypt, and mount them to the container.

$ cp /etc/letsencrypt/live/sub.example.com/fullchain.pem /srv/docker/keycloak/data/certs/tls.crt
$ cp /etc/letsencrypt/live/sub.example.com/privkey.pem /srv/docker/keycloak/data/certs/tls.key
$ chmod 755 /srv/docker/keycloak/data/certs/
$ chmod 604 /srv/docker/keycloak/data/certs/*

docker-compose.yml

In my case, I needed to use the host network of my docker host. This is not best practice and should not be required for your case. Please find information about configuration parameters in the documentation at hub.docker.com/r/jboss/keycloak/.

version: '3.7'

networks:
  default:
    external:
      name: host

services:
  keycloak:
    container_name: keycloak_app
    image: jboss/keycloak
    depends_on:
      - mariadb
    restart: always
    ports:
      - "8080:8080"
      - "8443:8443"
    volumes:
      - "/srv/docker/keycloak/data/certs/:/etc/x509/https"   # map certificates to container
    environment:
      KEYCLOAK_USER: <user>
      KEYCLOAK_PASSWORD: <pw>
      KEYCLOAK_HTTP_PORT: 8080
      KEYCLOAK_HTTPS_PORT: 8443
      KEYCLOAK_HOSTNAME: sub.example.ocm
      DB_VENDOR: mariadb
      DB_ADDR: localhost
      DB_USER: keycloak
      DB_PASSWORD: <pw>
    network_mode: host

  mariadb:
    container_name: keycloak_db
    image: mariadb
    volumes:
      - "/srv/docker/keycloak/data/keycloak_db:/var/lib/mysql"
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: <pw>
      MYSQL_DATABASE: keycloak
      MYSQL_USER: keycloak
      MYSQL_PASSWORD: <pw>
    network_mode: host

Final directory setup

This is how my final file and folder setup looks like.

$ cd /srv/docker/keycloak/
$ tree
.
├── config
│   └── docker-compose.yml
└── data
    ├── certs
    │   ├── tls.crt
    │   └── tls.key
    └── keycloak_db

Start container

Finally, I was able to start my software using docker-compose.

$ cd /srv/docker/keycloak/config/
$ sudo docker-compose up -d

We can see the mounted certificates within the container.

$ cd /srv/docker/keycloak/config/
$ sudo docker-compose up -d

We can doublecheck the mounted certificates within the container.

## open internal shell of keycloack container
$ sudo docker exec -it keycloak_app /bin/bash

## open directory of certificates
$ cd /etc/x509/https/
$ ll
-rw----r-- 1 root root 3586 Oct 30 14:21 tls.crt
-rw----r-- 1 root root 1708 Oct 30 14:20 tls.key

Considerung the setup from the docker-compose.yml, keycloak is now available at https://sub.example.com:8443

For anyone who is trying to run Keycloak with a passphrase protected private key file:

Keycloak runs the script /opt/jboss/tools/x509.sh to generate the keystore based on the provided files in /etc/x509/https as described in https://hub.docker.com/r/jboss/keycloak - Setting up TLS(SSL).

This script takes no passphrase into account unfortunately. But with a little modification at Docker build time you can fix it by yourself: Within your Dockerfile add:

RUN sed -i -e 's/-out "${KEYSTORES_STORAGE}\/${PKCS12_KEYSTORE_FILE}" \\/-out "${KEYSTORES_STORAGE}\/${PKCS12_KEYSTORE_FILE}" \\\n      -passin pass:"${SERVER_KEYSTORE_PASSWORD}" \\/' /opt/jboss/tools/x509.sh

This command modifies the script and appends the parameter to pass in the passphrase -passin pass:"${SERVER_KEYSTORE_PASSWORD}"

The value of the parameter is an environment variable which you are free to set: SERVER_KEYSTORE_PASSWORD

Tested with Keycloak 9.0.0

After some research the following method worked (for self-signed certs, I still have to figure out how to do with letsencrypt CA for prod)

generate a self-signed cert using the keytool

keytool -genkey -alias localhost -keyalg RSA -keystore keycloak.jks -validity 10950

convert .jks to .p12

keytool -importkeystore -srckeystore keycloak.jks -destkeystore keycloak.p12 -deststoretype PKCS12

generate .crt from .p12 keystore

openssl pkcs12 -in keycloak.p12 -nokeys -out tls.crt

generate .key from .p12 keystore

openssl pkcs12 -in keycloak.p12 -nocerts -nodes -out tls.key

Then use the tls.crt and tls.key for volume mount /etc/x509/https

Also, on the securing app, in the keycloak.json file specify the following properties

"truststore" : "path/to/keycloak.jks",
"truststore-password" : "<jks-pwd>",