wasmCloud Application Deployment Manager (wadm)

Wadm is a Wasm-native orchestrator for managing and scaling declarative wasmCloud applications.

Responsibilities

wadm is powerful because it focuses on a small set of core responsibilities, making it efficient and easy to manage.

• Manage application specifications - Manage applications which represent desired state. This includes the creation, deletion, upgrades and rollback of applications to previous versions. Application specifications are defined using the Open Application Model. For more information on wadm's specific OAM features, see our OAM README.
• Observe state - Monitor wasmCloud CloudEvents from all hosts in a lattice to build the current state.
• Reconcile with compensating commands - When the current state doesn't match the desired state, issue commands to wasmCloud hosts in the lattice with the control interface to reach desired state. Wadm is constantly reconciling and will react immediately to ensure applications stay deployed. For example, if a host stops, wadm will reconcile the host_stopped event and issue any necessary commands to start components on other available hosts.

Using wadm

Install & Run

You can easily run wadm by downloading the wash CLI, which automatically launches wadm alongside NATS and a wasmCloud host when you run wash up. You can use wash to query, create, and deploy applications.

wash up -d    # Start NATS, wasmCloud, and wadm in the background

Follow the wasmCloud quickstart to get started building and deploying an application, or follow the Deploying an application example below to simply try a deploy.

If you prefer to run wadm separately and/or connect to running wasmCloud hosts, you can instead opt for using the latest GitHub release artifact and executing the binary. Simply replace the latest version, your operating system, and architecture below. Please note that wadm requires a wasmCloud host version >=0.63.0

# Install wadm
curl -fLO https://github.com/wasmCloud/wadm/releases/download/<version>/wadm-<version>-<os>-<arch>.tar.gz
tar -xvf wadm-<version>-<os>-<arch>.tar.gz
cd wadm-<version>-<os>-<arch>
./wadm

Deploying an application

Copy the following manifest and save it locally as hello.yaml (you can also find it in the oam directory):

# Metadata
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: hello-world
  annotations:
    description: 'HTTP hello world demo'
spec:
  components:
    - name: http-component
      type: component
      properties:
        # Run components from OCI registries as below or from a local .wasm component binary.
        image: ghcr.io/wasmcloud/components/http-hello-world-rust:0.1.0
      traits:
        # One replica of this component will run
        - type: spreadscaler
          properties:
            instances: 1
    # The httpserver capability provider, started from the official wasmCloud OCI artifact
    - name: httpserver
      type: capability
      properties:
        image: ghcr.io/wasmcloud/http-server:0.22.0
      traits:
        # Link the HTTP server and set it to listen on the local machine's port 8080
        - type: link
          properties:
            target: http-component
            namespace: wasi
            package: http
            interfaces: [incoming-handler]
            source:
              config:
                - name: default-http
                  properties:
                    ADDRESS: 127.0.0.1:8080

Then use wash to deploy the manifest:

wash app deploy hello.yaml

🎉 You've just launched your first application with wadm! Try curl localhost:8080.

When you're done, you can use wash to undeploy the application:

wash app undeploy hello-world

Modifying applications

wadm supports upgrading applications by deploying new versions of manifests. Try changing the manifest you created above by updating the number of instances.

<<ELIDED>>
metadata:
  name: hello-world
  annotations:
    description: 'HTTP hello world demo'
spec:
  components:
    - name: http-component
      type: component
      properties:
        image: ghcr.io/wasmcloud/components/http-hello-world-rust:0.1.0
      traits:
        - type: spreadscaler
          properties:
            instances: 10 # Let's have 10!
<<ELIDED>>

Then simply deploy the new manifest:

wash app deploy hello.yaml

Now wasmCloud is configured to automatically scale your component to 10 instances based on incoming load.

🚧 Advanced

You can find a Docker Compose file for deploying an end-to-end multi-tenant example in the test directory.

In advanced use cases, wadm is also capable of:

• Monitoring multiple lattices.
• Running multiple instances to distribute load among multiple processes, or for a high-availability architecture.

🚧 Multi-lattice and multi-process functionality is somewhat tested, but not as rigorously as a single instance monitoring a single lattice. Proceed with caution while we do further testing.

API

Interacting with wadm is done over NATS on the root topic wadm.api.{prefix} where prefix is the lattice namespace prefix. For more information on this API, please consult the wadm Reference.

References

The wasmCloud Application Deployment Manager (wadm) originally came from the autonomous lattice controller RFC and then was reworked in version 0.4 in response to the tidying and productioning RFC.

• Autonomous Agents
• Autonomous Agent (Wikipedia)
• Control Loop
• Hashicorp Vault