Amalgam8 Registry

The Amalgam8 Registry is a multi-tenant, highly-available service for service registration and service discovery in microservice applications. For high availability, run the Registry in clustered mode. In clustered mode, the Registry provides eventual consistency for data synchronization across Registry instances.

The Registry is built using an extensible catalog model that allows the user to update the Amalgam8 Registry with information stored in other service registries such as Kubernetes, Consul, etc. In addition, the Registry can be used as a drop-in replacement for Netflix Eureka with full API compatibility. Eureka compatibility enables the Registry to be used with Java clients using Netflix Ribbon.

By default, the Registry operates without any authentication. It also supports two authentication mechanisms: a trusted auth mode for local testing and development, and a JWT auth mode for production deployments.

See https://www.amalgam8.io for an overview of the Amalgam8 project and https://www.amalgam8.io/docs for detailed documentation.

Usage

To get started, use the current stable version of the Registry from Docker Hub.

docker run amalgam8/a8-registry:latest -auth_mode=trusted

Command Line Flags and Environment Variables

The Amalgam8 Registry supports a number of configuration options, most of which are set through environment variables. The environment variables can be set via command line flags as well.

The following environment variables are available. All of them are optional.

Registry Configuration

Environment Key	Flag Name	Description	Default Value
API_PORT	--api_port	API port number	8080
LOG_LEVEL	--log_level	Logging level. Supported values are: debug, info, warn, error, fatal, panic	debug
LOG_FORMAT	--log_format	Logging format. Supported values are: text, json, logstash	text
NAMESPACE_CAPACITY	--namespace_capacity	maximum number of instances that may be registered in a namespace	-1 (no capacity limit)
DEFAULT_TTL	--default_ttl	Registry default instance time-to-live (TTL)	30s
MIN_TTL	--min_ttl	Minimum TTL that may be specified during registration	10s
MAX_TTL	--max_ttl	Maximum TTL that may be specified during registration	10m

Authentication and Authorization

The Amalgam8 Registry supports multi-tenancy by isolating each tenant into a separate namespace. A namespace is defined by an opaque string carried in the HTTP Authorization header of API requests. The following namespace authorization methods are supported and controlled via the AUTH_MODE environment variable (or --auth_mode flag):

• None: if no authorization mode is defined, all instances are registered into a default shared namespace.
• Trusted: namespace is retrieved directly from the Authorization header. This provides namespace separation in a trusted environment (e.g., single tenant with multiple applications or environments).
• JWT: encodes the namespace value in a signed JWT token claim.

Environment Key	Flag Name	Description	Default Value
AUTH_MODE	--auth_mode	Authentication modes. Supported values are: trusted, jwt	none (no isolation)
JWT_SECRET	--jwt_secret	Secret key for JWT authentication	none (must be set if AUTH_MODE is jwt)
REQUIRE_HTTPS	--require_https	Require clients to use HTTPS for API calls	false

If jwt is specified, JWT_SECRET (or --jwt_secret) must be set as well to allow encryption and decryption. Namespace value encoding must be present in every API call using HTTP Bearer Authorization:

Authorization: Bearer jwt.eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ...wifQ.Gbz4G_O...NqdY`

Clustering

Amalgam8 Registry uses a memory only storage solution, without persistency (although different storage backends can be implemented). To provide HA and scale, the Registry can be run in a cluster and supports replication between cluster members.

Peer discovery currently uses a shared volume between all members. The volume must be mounted RW into each container. We are exploring alternative discovery mechanisms.

Environment Key	Flag Name	Description	Default Value
CLUSTER_SIZE	--cluster_size	Cluster minimal healthy size, peers detecting a lower value will log errors	1 (standalone)
CLUSTER_DIR	--cluster_dir	Filesystem directory for cluster membership	none, must be specified for clustering to work
REPLICATION	--replication	Enable replication between cluster members	false
REPLICATION_PORT	--replication_port	Replication port number	6100
SYNC_TIMEOUT	--sync_timeout	Timeout for establishing connections to peers for replication	30s

Catalog Extensions

The Amalgam8 Registry supports read-only catalogs extensions. The content of each catalog extension (e.g., Kubernetes, Docker-Swarm, FileSystem, etc) is read by the Registry and returned to the user along with the content of the Registry itself.

Environment Key	Flag Name	Description	Default Value
K8S_URL	--k8s_url	Enable kubernetes catalog and specify the API server	(none)
K8S_TOKEN	--k8s_token	Kubernetes API token	(none)
FS_CATALOG	--fs_catalog	Enable FileSystem catalog and specify the directory of the config files. The format of the file names in the directory should be <namespace>.conf. See FileSystem catalog documentation for more information	(none)

REST API

Amalgam8 Registry API documentation is available in Swagger format.

Building from source

To build from source, clone this repository, and follow the instructions below.

Pre-requisites

• Docker engine >=1.10
• Go toolchain (tested with 1.6.x). See Go downloads and installation instructions.

Building a Docker Image

To build the docker image for the Amalgam8 Registry service, run the following commands:

cd $GOPATH/src/github.com/amalgam8/registry
make build docker

You should now have a docker image tagged a8-registry:latest.

Building an Executable

The Amalgam8 Registry can also be run outside of a docker container as a Go binary. This is not recommended for production, but it can be useful for development or easier integration with your local Go tools.

The following commands will build and run it as a Go binary:

cd $GOPATH/src/github.com/amalgam8/registry
make build
./bin/registry

Makefile Targets

The following Makefile targets are available.

Make Target	Description
build	(Default) build builds the Registry binary in the ./bin directory
precommit	precommit should be run by developers before committing code changes. It runs code formatting and checks.
test	test runs (short duration) tests using go test. You may also make test.all to include long running tests.
docker	docker packages the binary in a docker container
release	release builds a tarball with the Registry binary
clean	clean removes build artifacts. Note: this does not remove docker images

Continuous Integration with Travis CI

Continuous builds are run on Travis CI. These builds use the .travis.yml configuration.

Release Workflow

This section includes instructions for working with releases, and is intended for the project's maintainers (requires write permissions)

Creating a release

1. Set a version for the release, by incrementing the current version according to the semantic versioning guidelines. For example,

   export VERSION=v0.1.0

2. Update the APP_VER variable in the Makefile such that it matches with the VERSION variable above.

3. Create an annotated tag in your local copy of the repository:

   git tag -a -m "Release $VERSION" $VERSION [commit id]

   The [commit id] argument is optional. If not specified, HEAD is used.

4. Push the tag back to the Amalgam8 upstream repository on GitHub:

   git push upstream $VERSION

This command automatically creates a release object on GitHub, corresponding to the pushed tag. The release contains downloadable packages of the source code (both as .zip and .tag.gz archives).

1. Edit the CHANGELOG.md file, describing the changes included in this release.

2. Edit the GitHub release object, and add a title and description (according to CHANGELOG.md).

License

Copyright 2016 IBM Corporation

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Contributing

Contributions and feedback are welcome! Proposals and pull requests will be considered. Please see the CONTRIBUTING.md file for more information.