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olric-cloud-plugin

Discover nodes in cloud environments. Uses hashicorp/go-discover under the hood.

Install

Get the code:

go get -u github.com/buraksezer/olric-cloud-plugin

Usage

Load as compiled plugin

Build

With a properly configured Go environment:

go build -buildmode=plugin -o olric-cloud-plugin.so

If you want to strip debug symbols from the produced binary add -ldflags="-s -w" to build command.

Configuration

This plugin is only tested against Kubernetes.

Kubernetes

For the uses of olricd, the following block is going to loads and configures the plugin.

serviceDiscovery:
  provider: "k8s"
  path: "/path/to/olric-cloud-plugin.so"
  args: 'label_selector="run = olricd"'

Available configuration parameters for Kubernetes integration:

KeyDescription
kubeconfigPath to the kubeconfig file.
namespaceNamespace to search for pods (defaults to "default").
label_selectorLabel selector value to filter pods.
field_selectorField selector value to filter pods.
host_network"true" if pod host IP and ports should be used.

Sample usage:

...
args: 'label_selector="run = olricd"'
...

From go-discover's documentation:

The kubeconfig file value will be searched in the following locations:

  1. Use path from "kubeconfig" option if provided.
  2. Use path from KUBECONFIG environment variable.
  3. Use default path of $HOME/.kube/config

By default, the Pod IP is used to join. The "host_network" option may be set to use the Host IP. No port is used by default. Pods may set an annotation 'hashicorp/consul-auto-join-port' to a named port or an integer value. If the value matches a named port, that port will be used to join. Note that if "host_network" is set to true, then only pods that have a HostIP available will be selected. If a port annotation exists, then the port must be exposed via a HostPort as well, otherwise the pod will be ignored.

If you prefer to use Olric in embedded-member mode, the following code snipped will guide you:

c := olric.New("lan")
...
cd := &discovery.CloudDiscovery{}
labelSelector := fmt.Sprintf("app.kubernetes.io/name=%s,app.kubernetes.io/instance=%s", name, instance)
c.ServiceDiscovery = map[string]interface{}{
  "plugin":   cd,
  "provider": "k8s",
  "args":     fmt.Sprintf("namespace=%s label_selector=\"%s\"", namespace, labelSelector),
}

See details about how you deploy your Olric-based application on Kubernetes:

Docker Build & Push

Build a Docker image, in the root folder:

$ docker build -t $USERNAME/olric-cloud-plugin:$TAG .

Push the image to a registry:

$ docker push $USERNAME/olric-cloud-plugin:$TAG

See Dockerfile for details.

TODO

Test this plugin on the following cloud providers:

Contributions

Please don't hesitate to fork the project and send a pull request or just e-mail me to ask questions and share ideas.

License

The Apache License, Version 2.0 - see LICENSE for more details.