Installing Linkerd with Helm
Linkerd can optionally be installed via Helm rather than with the linkerd install
command.
Prerequisite: identity certificates
The identity component of Linkerd requires setting up a trust anchor certificate, and an issuer certificate with its key. These must use the ECDSA P-256 algorithm and need to be provided to Helm by the user (unlike when using the linkerd install
CLI which can generate these automatically). You can provide your own, or follow these instructions to generate new ones.
Adding Linkerd’s Helm repository
# To add the repo for Linkerd2 stable releases:
helm repo add linkerd https://helm.linkerd.io/stable
# To add the repo for Linkerd2 edge releases:
helm repo add linkerd-edge https://helm.linkerd.io/edge
The following instructions use the linkerd
repo. For installing an edge release, just replace with linkerd-edge
.
Helm install procedure
# set expiry date one year from now, in Mac:
exp=$(date -v+8760H +"%Y-%m-%dT%H:%M:%SZ")
# in Linux:
exp=$(date -d '+8760 hour' +"%Y-%m-%dT%H:%M:%SZ")
helm install linkerd2 \
--set-file identityTrustAnchorsPEM=ca.crt \
--set-file identity.issuer.tls.crtPEM=issuer.crt \
--set-file identity.issuer.tls.keyPEM=issuer.key \
--set identity.issuer.crtExpiry=$exp \
linkerd/linkerd2
Note
For Helm versions < v3, --name
flag has to specifically be passed. In Helm v3, It has been deprecated, and is the first argument as specified above.
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.yaml
file passed with a -f
option, or overriding specific values using the family of --set
flags like we did above for certificates.
Disabling The Proxy Init Container
If installing with CNI, make sure that you add the --set cniEnabled=true
flag to your helm install
command.
Setting High-Availability
The chart contains a file values-ha.yaml
that overrides some default values as to set things up under a high-availability scenario, analogous to the --ha
option in linkerd install
. Values such as higher number of replicas, higher memory/cpu limits and affinities are specified in that file.
You can get ahold of values-ha.yaml
by fetching the chart files:
helm fetch --untar linkerd/linkerd2
Then use the -f
flag to provide the override file, for example:
## see above on how to set $exp
helm install linkerd2 \
--set-file identityTrustAnchorsPEM=ca.crt \
--set-file identity.issuer.tls.crtPEM=issuer.crt \
--set-file identity.issuer.tls.keyPEM=issuer.key \
--set identity.issuer.crtExpiry=$exp \
-f linkerd2/values-ha.yaml \
linkerd/linkerd2
Note
For Helm versions < v3, --name
flag has to specifically be passed. In Helm v3, It has been deprecated, and is the first argument as specified above.
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 the config.linkerd.io/admission-webhooks: disabled
label. It is required for the control plane to work correctly. This means that the chart won’t work with Helm v2’s --namespace
option. If you’re relying on a separate tool to create the control plane namespace, make sure that:
- The namespace is labeled with
config.linkerd.io/admission-webhooks: disabled
- The
installNamespace
is set tofalse
The
namespace
variable is overridden with the name of your namespaceNote
In Helm v3 the --namespace
option must be used with an existing namespace.
Helm upgrade procedure
Make sure your local Helm repos are updated:
helm repo update
helm search linkerd2 -v stable-2.10.2
NAME CHART VERSION APP VERSION DESCRIPTION
linkerd/linkerd2 <chart-semver-version> stable-2.10.2 Linkerd gives you observability, reliability, and securit...
The helm upgrade
command has a number of flags that allow you to customize its behaviour. The ones that special attention should be paid to are --reuse-values
and --reset-values
and how they behave when charts change from version to version and/or overrides are applied through --set
and --set-file
. To summarize there are the following prominent cases that can be observed:
--reuse-values
with no overrides - all values are reused--reuse-values
with overrides - all except the values that are overridden are reused--reset-values
with no overrides - no values are reused and all changes from provided release are applied during the upgrade--reset-values
with overrides - no values are reused and changed from provided release are applied together with the overrides- no flag and no overrides -
--reuse-values
will be used by default - no flag and overrides -
--reset-values
will be used by default
Bearing all that in mind, you have to decide whether you want to reuse the values in the chart or move to the values specified in the newer chart. The advised practice is to use a values.yaml
file that stores all custom overrides that you have for your chart. Before upgrade, check whether there are breaking changes to the chart (i.e. renamed or moved keys, etc). You can consult the edge or the stable chart docs, depending on which one your are upgrading to. If there are, make the corresponding changes to your values.yaml
file. Then you can use:
helm upgrade linkerd2 linkerd/linkerd2 --reset-values -f values.yaml --atomic
The --atomic
flag will ensure that all changes are rolled back in case the upgrade operation fails