Argo CD Image Updater¶
A tool to automatically update the container images of Kubernetes workloads that are managed by Argo CD.
A note on the current status
Argo CD Image Updater was born just recently. It is not suitable for production use yet, and it might break things in unexpected ways.
You are welcome to test it out on non-critical environments, and to contribute by sending bug reports, enhancement requests and - most appreciated - pull requests.
There will be (probably a lot of) breaking changes from release to release as development progresses until version 1.0. We will do our best to indicate any breaking change and how to un-break it in the Changelog
The Argo CD Image Updater can check for new versions of the container images
that are deployed with your Kubernetes workloads and automatically update them
to their latest allowed version using Argo CD. It works by setting appropriate
application parameters for Argo CD applications, i.e. similar to
argocd app set --helm-set image.tag=v1.0.1 - but in a fully automated
Usage is simple: You annotate your Argo CD
Application resources with a list
of images to be considered for update, along with a version constraint to
restrict the maximum allowed new version for each image. Argo CD Image Updater
then regularly polls the configured applications from Argo CD and queries the
corresponding container registry for possible new versions. If a new version of
the image is found in the registry, and the version constraint is met, Argo CD
Image Updater instructs Argo CD to update the application with the new image.
Depending on your Automatic Sync Policy for the Application, Argo CD will either automatically deploy the new image version or mark the Application as Out Of Sync, and you can trigger the image update manually by syncing the Application. Due to the tight integration with Argo CD, advanced features like Sync Windows, RBAC authorization on Application resources etc. are fully supported.
- Updates images of apps that are managed by Argo CD and are either generated from Helm or Kustomize tooling
- Update app images according to different update strategies
semver: update to highest allowed version according to given image constraint,
latest: update to the most recently created image tag,
name: update to the last tag in an alphabetically sorted list
- Default support for widely used container registries:
- Docker Hub (docker.io)
- Google Container Registry (gcr.io)
- Red Hat Quay (quay.io)
- GitHub Container Registry (docker.pkg.github.com)
- Support for private container registries via configuration
- Ability to filter list of tags returned by a registry using matcher functions
- Support for custom, per-image pull secrets (using generic K8s secrets, K8s pull secrets or environment variables)
- Runs in a Kubernetes cluster or can be used stand-alone from the command line
- Ability to perform parallel update of applications
The two most important limitations first. These will most likely not change anywhere in the near future, because they are limitations by design.
Please make sure to understand these limitations, and do not send enhancement requests or bug reports related to the following:
The applications you want container images to be updated must be managed using Argo CD. There is no support for workloads not managed using Argo CD.
Argo CD Image Updater can only update container images for applications whose manifests are rendered using either Kustomize or Helm and - especially in the case of Helm - the templates need to support specifying the image's tag (and possibly name) using a parameter (i.e.
Otherwise, current known limitations are:
- Image pull secrets must exist in the same Kubernetes cluster where Argo CD Image Updater is running in (or has access to). It is currently not possible to fetch those secrets from other clusters.
A short note about Git and write-back¶
In its current incarnation, Argo CD Image Updater does not write back any of the changes to a Git repo. We are investigating ways to implement this much requested feature, but this will still take some time. We know how important this feature is for the community.
However, as Argo CD Image Updater leverages the Argo CD API, consider that the
changes that are made by Argo CD Image Updater only affect the Argo CD
Application resource. More precisely, it will update the
Spec to modify application parameters. Whenever Argo CD renders
the application's resources' manifests, it will take the parameters in the
application's spec into the consideration and replace any container image
references to the values stored in the
As long as your
Application resource does not live in Git (i.e. you have
created the application using the Web UI or via
argocd app create ... using
the CLI), there will be no benefit what so ever from writing to Git.