Похоже, что функция поиска репозитория Helm доступна только с версии 3.0.0.
Даже я попытался использовать последнюю версию v2.16.7, все равно не повезло.
$ helm version
Client: &version.Version{SemVer:"v2.16.7", GitCommit:"5f2584fd3d35552c4af26036f0c464191287986b", GitTreeState:"clean"}"
$ helm repo add bitnami https://charts.bitnami.com/bitnami
"bitnami" has been added to your repositories
$ helm repo update --debug
Hang tight while we grab the latest from your chart repositories...
...Skip local chart repository
...Successfully got an update from the "stable" chart repository
...Successfully got an update from the "bitnami" chart repository
Update Complete.
$ helm repo list
NAME URL
stable https://kubernetes-charts.storage.googleapis.com
local http://127.0.0.1:8879/charts
bitnami https://charts.bitnami.com/bitnami
$ helm search repo bitnami/postgresql
No results found
Но это хорошо работает с версией 3.0.0 и выше.
$ helm version
version.BuildInfo{Version:"v3.0.0", GitCommit:"e29ce2a54e96cd02ccfce88bee4f58bb6e2a28b6", GitTreeState:"clean", GoVersion:"go1.13.4"}
$ helm repo add bitnami https://charts.bitnami.com/bitnami
"bitnami" has been added to your repositories
$ helm repo update --debug
Hang tight while we grab the latest from your chart repositories...
...Successfully got an update from the "bitnami" chart repository
Update Complete. ⎈ Happy Helming!⎈
$ helm repo list
NAME URL
bitnami https://charts.bitnami.com/bitnami
$ helm search repo bitnami/postgresql
NAME CHART VERSION APP VERSION DESCRIPTION
bitnami/postgresql 8.10.2 11.8.0 Chart for PostgreSQL, an object-relational data...
bitnami/postgresql-ha 3.2.7 11.8.0 Chart for PostgreSQL with HA architecture (usin...