Edge Delta Agent Updater

Agent updater is a configurable minimal program that helps with updating your Kubernetes resources. It is designed to be used to update daemonset and deployment images, but can be used to update any spec property of these resources.

Usage

Image

The latest updater image can be found in the public Google Container Registry: gcr.io/edgedelta/agent-updater:latest.

You can also build the image yourself with several options.

Ko

Ko is a simple container image builder for Go applications. To install ko, run the following command:

go install github.com/google/ko@latest

To build the image, run the following command:

ko build --local --platform=all -B ./cmd/agent-updater

Docker

To build the image using Docker, you can use the Dockerfile under the root directory. To build the image, run the following command:

docker build . -t edgedelta/agent-updater:latest

Configuration

The updater can be configured using a YAML configuration file. The configuration file can be passed to the updater using the --config flag. The configuration file defines the resources to be updated, the API to be used to fetch the latest version, and the logging configuration.

Entities

Entities are the resources to be updated. The updater supports updating the following Kubernetes resources:

• DaemonSet
• Deployment

Entities are defined under the entities list in the configuration file. The following is an example of a configuration file with two entities:

entities:
- id: 111-222-333
  image: some-agent
  paths:
  - default:ds/my-agent:spec.template.spec.containers[0].image
- id: 444-555-666
  image: some-other-agent
  paths:
  - default:ds/my-other-agent:spec.template.spec.containers[0].image

Property	Type	Description	Required
id	string	Unique ID of the resource	Yes
image	string	Resource's image kind	Yes
paths	[]string	K8s object paths of the properties to be updated	Yes

API

The API is used to fetch the latest version of the resource. The updater supports HTTP REST APIs.

The API is defined under the api section in the configuration file. The following is an example API configuration:

api:
  base_url: http://localhost:8080
  auth:
    header_key: Authorization
    header_value: 'Some_token'
  latest_tag:
    endpoint: /latest-version
  metadata:
    endpoint: /metadata
  log_upload:
    enabled: true
    method: PUT
    encoding:
      type: raw
      options:
        delimiter: '\n'
    compression: gzip
    presigned_upload_url:
      endpoint: /log-upload-link
      params:
        query:
          size: '{{ .ctx.size }}'
          format: json
          compression: gzip

Property	Type	Description	Required
base_url	string	Base URL of the API	Yes
auth	APIAuth	Authentication configuration	No
latest_tag	EndpointConfig	Configuration for fetching the latest version	Yes
metadata	EndpointConfig	Configuration for fetching the metadata	Yes
log_upload	LogUploadConfig	Configuration for uploading logs	No

Installation

The updater can be deployed to a Kubernetes cluster using the latest image from the public Google Container Registry.

1. Replace the data.updater-config.yml under the examples/cronjob.yml with your configuration file content.
2. Run the following command to deploy the updater:

chmod +x ./examples/deploy.sh
./examples/deploy.sh

3. To verify that the updater is working, you can check the logs of the updater pod:

kubectl logs -f updater-<random-id>