OpenCHAMI Cloud-Init Server

Summary of Repo

The OpenCHAMI cloud-init service retrieves detailed inventory information from SMD and uses it to create cloud-init payloads customized for each node in an OpenCHAMI cluster.

Table of Contents

1. About / Introduction
2. Build / Install
   • Environment Variables
   • Building Locally with GoReleaser
3. Running the Service
   • Cluster Name
   • Fake SMD Mode
   • Impersonation
   • Nocloud-net Datasource
4. Testing the Service
   • Basic Endpoint Testing
   • Meta-data
   • User-data
   • Vendor-data
5. Group Handling and Overrides
   • Updating Group Data with a Simple Jinja Example
   • Complex Base64 Example
   • Cluster Defaults and Instance Overrides
     • Set Cluster Defaults
     • Override Instance Data
6. More Reading

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About / Introduction

The OpenCHAMI Cloud-Init Service is designed to generate cloud-init configuration for nodes in an OpenCHAMI cluster. The new design pushes the complexity of merging configurations into the cloud-init client rather than the server. This README provides instructions based on the Demo.md file for running and testing the service.

This service provides configuration data to cloud-init clients via the standard nocloud-net datasource. The service merges configuration from several sources:

• SMD data (or simulated data in development mode)
• User-supplied JSON (for custom configurations)
• Cluster defaults and group overrides

Cloud-init on nodes retrieves data in a fixed order:

1. /meta-data – YAML document with system configuration.
2. /user-data - a document which can be any of the user data formats
3. /vendor-data – Vendor-supplied configuration via include-file mechanisms.
4. /network-config – An optional document in one of two network configuration formats. This is only requested if configured to do so with a kernel parameter or through cloud-init configuration in the image. NB: OpenCHAMI doesn't support delivering network-config via the cloud-init server today

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Build / Install

This project uses GoReleaser for building and releasing, embedding additional metadata such as commit info, build time, and version. Below is a brief overview for local builds.

Environment Variables

To include detailed metadata in your builds, set the following:

• GIT_STATE: clean if your repo is clean, dirty if uncommitted changes exist
• BUILD_HOST: Hostname of the build machine
• GO_VERSION: Version of Go used (for consistent versioning info)
• BUILD_USER: Username of the person/system performing the build

export GIT_STATE=$(if git diff-index --quiet HEAD --; then echo 'clean'; else echo 'dirty'; fi)
export BUILD_HOST=$(hostname)
export GO_VERSION=$(go version | awk '{print $3}')
export BUILD_USER=$(whoami)

Building Locally with GoReleaser

1. Install GoReleaser following their documentation.

2. Run in snapshot mode to build locally without releasing:

   goreleaser release --snapshot --clean

3. Check the dist/ directory for compiled binaries, which will include the injected metadata.

Note

If you encounter errors, ensure your GoReleaser version matches the one used in the Release Action.

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Running the Service

Cluster Name

Each instance of cloud-init is linked to a single SMD and operates for a single cluster. Until the cluster name is automatically available via your inventory system, you must specify it on the command line using the -cluster-name flag.

Example:

-cluster-name venado

Fake SMD Mode

For development purposes, you can run the cloud-init server without connecting to a real SMD instance. By setting the environment variable CLOUD_INIT_SMD_SIMULATOR to true, the service will generate a set of simulated nodes.

Example command:

CLOUD_INIT_SMD_SIMULATOR=true dist/cloud-init_darwin_arm64_v8.0/cloud-init-server -cluster-name venado -insecure -impersonation=true

Impersonation

By default, the service determines what configuration to return based on the IP address of the requesting node. For testing, impersonation routes can be enabled with the -impersonation=true flag.

Sample commands:

curl http://localhost:27777/cloud-init/admin/impersonation/x3000c1b1n1/meta-data

Nocloud-net Datasource

cloud-init=enabled ds=nocloud-net;s=http://192.0.0.1/cloud-init

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Testing the Service

The following testing steps (adapted from Demo.md) help you verify that the service is functioning correctly.

Basic Endpoint Testing

Start the Service in Fake SMD Mode (if desired):

Example:

CLOUD_INIT_SMD_SIMULATOR=true dist/cloud-init_darwin_arm64_v8.0/cloud-init-server -cluster-name venado -insecure -impersonation=true

Query the Standard Endpoints:

Meta-data:

curl http://localhost:27777/cloud-init/meta-data

You should see a YAML document with instance information (e.g., instance-id, cluster-name, etc.).

User-data:

curl http://localhost:27777/cloud-init/user-data

For now, this returns a blank cloud-config document:

#cloud-config

Vendor-data:

curl http://localhost:27777/cloud-init/vendor-data

Vendor-data typically includes include-file directives pointing to group-specific YAML files:

#include
http://192.168.13.3:8080/all.yaml
http://192.168.13.3:8080/login.yaml
http://192.168.13.3:8080/compute.yaml

Group Handling and Overrides

The service supports advanced configuration through group handling and instance overrides.

Updating Group Data with a Simple Jinja Example

This example sets a syslog aggregator via jinja templating. The group data is stored under the group name and then used in the vendor-data file.

curl -X POST http://localhost:27777/cloud-init/admin/groups/ \
    -H "Content-Type: application/json" \
    -d '{
        "name": "x3001",
        "description": "Cabinet x3001",
        "data": {
            "syslog_aggregator": "192.168.0.1"
        },
        "file": {
            "content": "#template: jinja\n#cloud-config\nrsyslog:\n  remotes: {x3001: {{ vendor_data.groups[\"x3001\"].syslog_aggregator }}}\n  service_reload_command: auto\n",
            "encoding": "plain"
        }
    }'

Complex Base64 Example

To add more sophisticated vendor-data (for example, installing the slurm client), you can encode a complete cloud-config in base64. (See the script in Demo.md for a complete example.)

Cluster Defaults and Instance Overrides

Set Cluster Defaults:

curl -X POST http://localhost:27777/cloud-init/admin/cluster-defaults/ \
    -H "Content-Type: application/json" \
    -d '{
        "cloud-provider": "openchami",
        "region": "us-west-2",
        "availability-zone": "us-west-2a",
        "cluster-name": "venado",
        "public-keys": [
            "ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEArV2...",
            "ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEArV3..."
        ]
    }'

Override Instance Data:

curl -X PUT http://localhost:27777/cloud-init/admin/instance-info/x3000c1b1n1 \
    -H "Content-Type: application/json" \
    -d '{
        "local-hostname": "compute-1",
        "instance-type": "t2.micro"
    }'

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More Reading

• Official cloud-init documentation
• OpenCHAMI TPM-manager service
• GoReleaser Documentation
• SMD Documentation