Helm

Installing with Helm

cert-manager provides Helm charts as a first-class method of installation on both Kubernetes and OpenShift.

Be sure never to embed cert-manager as a sub-chart of other Helm charts; cert-manager manages non-namespaced resources in your cluster and care must be taken to ensure that it is installed exactly once.

Prerequisites

Install Helm version 3 or later.
Install a supported version of Kubernetes or OpenShift.
Read Compatibility with Kubernetes Platform Providers if you are using Kubernetes on a cloud platform.

Steps

1. Add the Helm repository

This repository is the only supported source of cert-manager charts. There are some other mirrors and copies across the internet, but those are entirely unofficial and could present a security risk.

Notably, the "Helm stable repository" version of cert-manager is deprecated and should not be used.

helm repo add jetstack https://charts.jetstack.io

2. Update your local Helm chart repository cache:

helm repo update

3. Install `CustomResourceDefinitions`

cert-manager requires a number of CRD resources, which can be installed manually using kubectl, or using the installCRDs option when installing the Helm chart. Both options are described below and will achieve the same result but with varying consequences. You should consult the CRD Considerations section below for details on each method.

Option 1: installing CRDs with `kubectl`

Recommended for production installations

kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.13.6/cert-manager.crds.yaml

Option 2: install CRDs as part of the Helm release

Recommended for ease of use & compatibility

To automatically install and manage the CRDs as part of your Helm release, you must add the --set installCRDs=true flag to your Helm installation command.

Uncomment the relevant line in the next steps to enable this.

Note that if you're using a helm version based on Kubernetes v1.18 or below (Helm v3.2), installCRDs will not work with cert-manager v0.16. See the v0.16 upgrade notes for more details.

4. Install cert-manager

To install the cert-manager Helm chart, use the Helm install command as described below.

helm install \
  cert-manager jetstack/cert-manager \
  --namespace cert-manager \
  --create-namespace \
  --version v1.13.6 \
  # --set installCRDs=true

A full list of available Helm values is on cert-manager's ArtifactHub page.

The example below shows how to tune the cert-manager installation by overwriting the default Helm values:

helm install \
  cert-manager jetstack/cert-manager \
  --namespace cert-manager \
  --create-namespace \
  --version v1.13.6 \
  # --set installCRDs=true
  --set prometheus.enabled=false \  # Example: disabling prometheus using a Helm parameter
  --set webhook.timeoutSeconds=4   # Example: changing the webhook timeout using a Helm parameter

Once you have deployed cert-manager, you can verify the installation.

Installing cert-manager as subchart

If you have configured cert-manager as a subchart all the components of cert-manager will be installed into the namespace of the helm release you are installing.

There may be a situation where you want to specify the namespace to install cert-manager different to the umbrella chart's namespace.

This is a known issue with helm and subcharts, that you can't specify the namespace for the subchart and is being solved by most public charts by allowing users to set the namespace via the values file, but needs to be a capability added to the chart by the maintainers.

This capability is now available in the cert-manager chart and can be set either in the values file or via the --set switch.

Example usage

Below is an example Chart.yaml with cert-manager as a subchart

apiVersion: v2
name: example_chart
description: A Helm chart with cert-manager as subchart
type: application
version: 0.1.0
appVersion: "0.1.0"
dependencies:
  - name: cert-manager
    version: v1.13.6
    repository: https://charts.jetstack.io
    alias: cert-manager
    condition: cert-manager.enabled

You can then override the namespace in 2 ways:

In Values.yaml file

cert-manager: #defined by either the name or alias of your dependency in Chart.yaml
  namespace: security

In the helm command using --set

helm install example example_chart \
  --namespace example \
  --create-namespace \
  --set cert-manager.namespace=security

The above example will install cert-manager into the security namespace.

Output YAML

Instead of directly installing cert-manager using Helm, a static YAML manifest can be created using the Helm template command. This static manifest can be tuned by providing the flags to overwrite the default Helm values:

helm template \
  cert-manager jetstack/cert-manager \
  --namespace cert-manager \
  --create-namespace \
  --version v1.13.6 \
  # --set prometheus.enabled=false \   # Example: disabling prometheus using a Helm parameter
  # --set installCRDs=true \           # Uncomment to also template CRDs
  > cert-manager.custom.yaml

Uninstalling

Warning: To uninstall cert-manager you should always use the same process for installing but in reverse. Deviating from the following process whether cert-manager has been installed from static manifests or Helm can cause issues and potentially broken states. Please ensure you follow the below steps when uninstalling to prevent this happening.

Before continuing, ensure that all cert-manager resources that have been created by users have been deleted. You can check for any existing resources with the following command:

kubectl get Issuers,ClusterIssuers,Certificates,CertificateRequests,Orders,Challenges --all-namespaces

Once all these resources have been deleted you are ready to uninstall cert-manager using the procedure determined by how you installed.

Uninstalling with Helm

Uninstalling cert-manager from a helm installation is a case of running the installation process, in reverse, using the delete command on both kubectl and helm.

helm --namespace cert-manager delete cert-manager

Next, delete the cert-manager namespace:

kubectl delete namespace cert-manager

Finally, delete the cert-manager CustomResourceDefinitions using the link to the version vX.Y.Z you installed:

Warning: This command will also remove installed cert-manager CRDs. All cert-manager resources (e.g. certificates.cert-manager.io resources) will be removed by Kubernetes' garbage collector.

kubectl delete -f https://github.com/cert-manager/cert-manager/releases/download/vX.Y.Z/cert-manager.crds.yaml

Note: If you used helm to install the CRDs with the installCRDs=true value for the chart, then the CRDs will have been automatically removed and you do not need to run this final kubectl command.

Namespace Stuck in Terminating State

If the namespace has been marked for deletion without deleting the cert-manager installation first, the namespace may become stuck in a terminating state. This is typically due to the fact that the APIService resource still exists however the webhook is no longer running so is no longer reachable. To resolve this, ensure you have run the above commands correctly, and if you're still experiencing issues then run:

kubectl delete apiservice v1beta1.webhook.cert-manager.io

CRD considerations

kubectl installation

When installing CRDs with kubectl, you will need to upgrade these in tandem with your cert-manager installation upgrades. This approach may be useful when you do not have the ability to install CRDs all the time in your environment. If you do not upgrade these as you upgrade cert-manager itself, you may miss out on new features for cert-manager.

Benefits:

CRDs will not change once applied

Drawbacks:

CRDs are not automatically updated and need to be reapplied before upgrading cert-manager
You may have different installation processes for CRDs compared to the other resources.

helm installation

cert-manager does not use the official helm method of installing CRD resources. This is because it makes upgrading CRDs impossible with helm CLI alone. The helm team explain the limitations of their approach here.

cert-manager actually bundles the CRDs along with the other templates in the Helm chart. This means that Helm manages these resources so they are upgraded with your cert-manager release when you use installCRDs: true in your values file or CLI command. This does also mean that if you uninstall the release, the CRDs will also be uninstalled. If that happens then you will loose all instances of those CRDs, e.g. all Certificate resources in the cluster. You should consider if this is likely to happen to you and have a mitigation, such as backups or a means to reapply resources from an Infrastructure as Code (IaC) pattern.

Note this also means a typo like installCRD: true would be an invalid value and helm would silently ignore this and remove the CRDs when you next run your helm upgrade.