Hi, so by default, the chart will create a secret for you (based on the username and password supplied in the chart). It will be named the same as your helm deployment, so if you do helm install foo, it will create a secret called foo.
If the password is not specified, the chart will generate a password for you and create an initial secret. As that password is regenerated with each update of the helm chart, the password would normally be rotated, which is undesirable. To prevent this happening, if the secret already exists, then the chart will reuse any existing password it finds. See https://github.com/couchbase-partners/helm-charts/blob/master/couchbase-operator/templates/_helpers.tpl#L126
Therefore, to create a cluster with admin credentials that are not created by the helm chart, if the cluster is named foo, create a secret named foo in the namespaces you wish to create the cluster in, with the username and password keys populated.
To update to “doing your own thing” on an existing cluster, the same applies, do nothing, unset the password in the chart and it will still function, using what is already set. The helm chart will always use the chart defined username, so ensure the secret and chard variable match, Also you cannot change the admin username.
I should point out that changing the password is not supported until 2.1 is released.