This Docker images provides the confluentinc/cp-schema-registry image as base with the mDNS/ZeroConf stack on top. So you can enjoy the app while it is accessible by default as schema-registry.local. (Port 80)
- Requirements
- Getting starting
- docker-compose usage example
- Host configs
- Configure a different mDNS hostname
- Other top level domains
- Further reading
- Host enabled Avahi daemon
- Host enabled mDNS NSS lookup
To get a Schema Registry service up and running create a
docker-compose.yml
and insert the following snippet:
zookeeper:
image: wurstmeister/zookeeper
ports:
- "2181"
kafka:
image: hausgold/kafka
environment:
# Mind the .local suffix
- MDNS_HOSTNAME=kafka.local
ports:
# The ports are just for you to know when configure your
# container links, on depended containers
- "9092"
links:
# Link to the ZooKeeper instance for advertising
- zookeeper
schema-registry:
image: hausgold/schema-registry
environment:
# Mind the .local suffix
MDNS_HOSTNAME: schema-registry.local
# Defaults to zookeeper:2181
SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL: zookeeper:2181
links:
- zookeeper
Afterwards start the service with the following command:
$ docker-compose up
Install the nss-mdns package, enable and start the avahi-daemon.service. Then, edit the file /etc/nsswitch.conf and change the hosts line like this:
hosts: ... mdns4_minimal [NOTFOUND=return] resolve [!UNAVAIL=return] dns ...
The magic environment variable is MDNS_HOSTNAME. Just pass it like that to your docker run command:
$ docker run --rm -e MDNS_HOSTNAME=something.else.local hausgold/schema-registry
This will result in something.else.local.
You can also configure multiple aliases (CNAME's) for your container by passing the MDNS_CNAMES environment variable. It will register all the comma separated domains as aliases for the container, next to the regular mDNS hostname.
$ docker run --rm \
-e MDNS_HOSTNAME=something.else.local \
-e MDNS_CNAMES=nothing.else.local,special.local \
hausgold/schema-registry
This will result in something.else.local, nothing.else.local and special.local.
By default .local is the default mDNS top level domain. This images does not force you to use it. But if you do not use the default .local top level domain, you need to configure your host avahi to accept it.
- Docker/mDNS demo: https://github.com/Jack12816/docker-mdns
- Archlinux howto: https://wiki.archlinux.org/index.php/avahi
- Ubuntu/Debian howto: https://wiki.ubuntuusers.de/Avahi/