ca-injector

FOR DEVELOPMENT AND TESTING PURPOSES ONLY

This is a kubernetes MutatingAdmissionWebhook to inject certificate bundles into pods based on labels and annotations. With that off-the-shelf containers can be deployed in clusters with custom certificate authorities, with minimal disruption and minimal maintenance. No more creating images from upstream base images just to ADD custom-ca.crt /usr/local/share/ca-certificates/ and RUN update-ca-certificates etc.

This webhook will be triggered in following cases:

• object label ca-injector.zeiss.com/inject: "true"
• namespace label ca-injector.zeiss.com/inject: "true" and object label ca-injector.zeiss.com/inject does not exist
• deployment setting admissionWebhook.enableNamespacesByDefault: true (helm chart) and namespace/object label ca-injector.zeiss.com/inject does not exist

If triggered, this webhook does three things:

1. Add a volume to the pod referencing a certificate bundle specified by the value of the object annotation ca-injector.zeiss.com/inject-ca-from or the deployment setting caBundle.configMap (helm chart). The value should correspond with a config map in the same namespace as the pod which has the key ca.crt containing the CA bundle content.
2. Add this volume to all containers and init containers as a volume mount
3. Add the SSL_CERT_FILE and NODE_EXTRA_CA_CERTS environment variable respected by OpenSSL and most tls libraries.

It is strongly recommended to use this webhook with replicator or trust-manager for a consistent experience across namespaces.

Usage

Helm must be installed to use the chart. Please refer to Helm's documentation to get started.

Once Helm has been set up correctly, add the repo as follows:

helm repo add ca-injector https://zeiss.github.io/ca-injector

If you had already added this repo earlier, run helm repo update to retrieve the latest versions of the packages. You can then run helm search repo ca-injector to see the charts.

To install the ca-injector chart:

helm install ca-injector ca-injector/ca-injector

To uninstall the chart:

helm delete ca-injector

Example

#TODO Deploy this in your cluster (see Usage chapter) and create a CA bundle as e.g. foo-crt config map, with the key ca.crt:

kubectl create configmap foo-crt --from-file=ca.crt=my-bundle.crt

Use this CA bundle by defining the label ca-injector.zeiss.com/inject:true and the annotation ca-injector.zeiss.com/inject-ca-from: foo-crt on your pod or in your helm chart's appropriate annotations section. ca.crt can be changed by configuration caBundle.crt in any of the typical ways (config files at /etc/ca-injector.yaml, $HOME/.config/ca-injector.yaml, or environment variable CAINJECTOR_CABUNDLE_CRT).

Release

App

To trigger a new tagged docker build, create a PR with label 'app-release'. The app Version within the helm chart will be used as reference for the container tag. This will be done automatically by below mentioned workflow.

Helm

In case the appVersion is increased, the helm Chart version should also be increased. In case the helm Chart version is increased, the appVersion does not have to be increased as well.

Option 1: Manually set version and/or appVersion within Helm Chart. The Helm release workflow will create a new release in case the helm Chart version has changed.

Option 2: Add one or two(app and helm) of the following labels to your PR:

• app-major
• app-minor
• app-patch
• helm-major
• helm-minor
• helm-patch

According to the label, appVersion and/or helm version will be bumped and a PullRequest will be created. The Pull request will include label 'app-release' to trigger above mentioned workflow. After this PR has benn closed, the Helm release workflow will create a new release in case the helm Chart version has changed.