Installing Linkerd with Helm

Linkerd can optionally be installed via Helm rather than with the linkerdinstall command.

Prerequisite: identity certificates

The identity component of Linkerd requires setting up a trust anchorcertificate, and an issuer certificate with its key. These need to be providedto Helm by the user (unlike when using the linkerd install CLI which cangenerate these automatically). You can provide your own, or follow theseinstructions to generate new ones.

Adding Linkerd’s Helm repository

  1. # To add the repo for Linkerd2 stable releases:
  2. helm repo add linkerd https://helm.linkerd.io/stable
  4. # To add the repo for Linkerd2 edge releases:
  5. helm repo add linkerd-edge https://helm.linkerd.io/edge

The following instructions use the linkerd repo. For installing an edgerelease, just replace with linkerd-edge.

Helm install procedure

  1. # set expiry date one year from now, in Mac:
  2. exp=$(date -v+8760H +"%Y-%m-%dT%H:%M:%SZ")
  3. # in Linux:
  4. exp=$(date -d '+8760 hour' +"%Y-%m-%dT%H:%M:%SZ")
  6. helm install \
  7.   --name=linkerd2 \
  8.   --set-file Identity.TrustAnchorsPEM=ca.crt \
  9.   --set-file Identity.Issuer.TLS.CrtPEM=issuer.crt \
  10.   --set-file Identity.Issuer.TLS.KeyPEM=issuer.key \
  11.   --set Identity.Issuer.CrtExpiry=$exp \
  12.   linkerd/linkerd2

The chart values will be picked from the chart’s values.yaml file.

You can override the values in that file by providing your own values.yamlfile passed with a -f option, or overriding specific values using the family of—set flags like we did above for certificates.

Setting High-Availability

The chart contains a file values-ha.yaml that overrides somedefault values as to set things up under a high-availability scenario, analogousto the —ha option in linkerd install. Values such as higher number ofreplicas, higher memory/cpu limits and affinities are specified in that file.

You can get ahold of values-ha.yaml by fetching the chart files:

  1. helm fetch --untar linkerd/linkerd2

Then use the -f flag to provide the override file, for example:

  1. ## see above on how to set $exp
  2. helm install \
  3.   --name=linkerd2 \
  4.   --set-file Identity.TrustAnchorsPEM=ca.crt \
  5.   --set-file Identity.Issuer.TLS.CrtPEM=issuer.crt \
  6.   --set-file Identity.Issuer.TLS.KeyPEM=issuer.key \
  7.   --set Identity.Issuer.CrtExpiry=$exp \
  8.   -f linkerd2/values-ha.yaml \
  9.   linkerd/linkerd2

Customizing the Namespace

To install Linkerd to a different namespace than the default linkerd,override the Namespace variable.

By default, the chart creates the control plane namespace with theconfig.linkerd.io/admission-webhooks: disabled label. It is required for thecontrol plane to work correctly. This means that the chart won’t work withHelm v2’s —namespace option. If you’re relying on a separate tool to createthe control plane namespace, make sure that:

  • The namespace is labeled with linkerd.io/admission-webhooks: disabled
  • The InstallNamespace is set to false
  • The Namespace variable is overridden with the name of your namespace

NoteIn Helm v3 the —namespace option must be used with an existing namespace.

Helm upgrade procedure

Make sure your local Helm repos are updated:

  1. helm repo update
  3. helm search linkerd2 -v stable-2.6.0
  4. NAME                    CHART VERSION          APP VERSION            DESCRIPTION
  5. linkerd/linkerd2        <chart-semver-version> stable-2.6.0    Linkerd gives you observability, reliability, and securit...

Use the helm upgrade command to upgrade the chart:

  1. helm upgrade linkerd2 linkerd/linkerd2 --reuse-values