When acme issuer sets "disableAccountKeyGeneration: true", updating privateKeySecretRef secret won't change the acme account.

cert-manager installed with cert-manager-operator-bundle-container-v1.10.2-18 on OCP 4.13.0-0.nightly-2023-02-27-101545

Always

1. Install OCP env. Then install cert-manager Operator for Red Hat OpenShift.

2. Prepare secrets
$ aws_access_key_id=$(grep aws_access_key_id ~/.aws/credentials | cut -d = -f 2)
$ aws_secret_access_key=$(grep aws_secret_access_key ~/.aws/credentials | cut -d = -f 2)

$ oc create secret generic route53-creds --from-literal=aws_access_key_id="$aws_access_key_id" --from-literal=aws_secret_access_key="$aws_secret_access_key" -n cert-manager

3. Create clusterissuer one
$ cat cluster-issuer-one.yaml
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-one
spec:
  acme:
    preferredChain: ""
    privateKeySecretRef:
      name: letsencrypt-one
    server: https://acme-staging-v02.api.letsencrypt.org/directory
    solvers:
    - selector:
        dnsZones:
          - qe1.devcluster.openshift.com
      dns01:
        route53:
          accessKeyIDSecretRef:
            key: aws_access_key_id
            name: route53-creds
          hostedZoneID: <snipped_hosted_zone_id>
          region: us-east-1
          secretAccessKeySecretRef:
            key: aws_secret_access_key
            name: route53-creds

$ oc create -f cluster-issuer-one.yaml

$ oc get clusterissuer -o wide
NAME              READY   STATUS                                                 AGE
letsencrypt-one   True    The ACME account was registered with the ACME server   2m11s

$ oc get clusterissuer letsencrypt-one -o yaml
...
    uri: https://acme-staging-v02.api.letsencrypt.org/acme/acct/90569434
...

Save the secret letsencrypt-one:
$ oc get secret letsencrypt-one -n cert-manager -o yaml > secret-letsencrypt-one.yaml

4. Create cluster issuer two
$ sed 's/letsencrypt-one/letsencrypt-two/g' cluster-issuer-one.yaml | oc create -f -
clusterissuer.cert-manager.io/letsencrypt-two created

$ oc get clusterissuer letsencrypt-two -o yaml
...
    uri: https://acme-staging-v02.api.letsencrypt.org/acme/acct/90750464
...

Save the secret letsencrypt-two:
$ oc get secret letsencrypt-two -n cert-manager -o yaml > secret-letsencrypt-two.yaml

5. Create a new clusterissuer using existing privateKeySecretRef account of "letsencrypt-one" with disableAccountKeyGeneration:
$ sed 's/letsencrypt-one/letsencrypt-one/g' secret-letsencrypt-one.yaml | oc create -n cert-manager -f -
secret/letsencrypt created

$ cat cluster-issuer-using-existing-account.yaml # it uses secret "letsencrypt" which includes same account as secret "letsencrypt-one"
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt
spec:
  acme:
    disableAccountKeyGeneration: true
    preferredChain: ""
    privateKeySecretRef:
      key: tls.key
      name: letsencrypt
...snipped lines which are same as previous yaml file...

$ oc create -f cluster-issuer-using-existing-account.yaml
clusterissuer.cert-manager.io/letsencrypt created

$ oc get clusterissuer letsencrypt -o yaml
...
    uri: https://acme-staging-v02.api.letsencrypt.org/acme/acct/90569434
...

We can see it uses same account 90569434 as previous.

6. Update the content of secret "letsencrypt" to be the content of secret letsencrypt-two.
$ sed 's/letsencrypt-two/letsencrypt/g' secret-letsencrypt-two.yaml | oc replace -n cert-manager -f -
secret/letsencrypt replaced

Wait a moment, check the account in clusterissuer "letsencrypt" again, it is still account 90569434.

7. Change privateKeySecretRef secret name
$ oc edit clusterissuer letsencrypt # change secret name from "letsencrypt" to "letsencrypt-two" 

Wait a moment, check the account in clusterissuer "letsencrypt" again, it is still account 90569434.

8. Check logs of cert-manager
$ oc logs cert-manager-d464b7449-5m7nn -n cert-manager
I0302 04:18:03.215124       1 setup.go:202] cert-manager/clusterissuers "msg"="skipping re-verifying ACME account as cached registration details look sufficient" "related_resource_kind"="Secret" "related_resource_name"="letsencrypt" "related_resource_namespace"="cert-manager" "resource_kind"="ClusterIssuer" "resource_name"="letsencrypt" "resource_namespace"="" "resource_version"="v1"
I0302 05:19:51.202405       1 setup.go:202] cert-manager/clusterissuers "msg"="skipping re-verifying ACME account as cached registration details look sufficient" "related_resource_kind"="Secret" "related_resource_name"="letsencrypt-two" "related_resource_namespace"="cert-manager" "resource_kind"="ClusterIssuer" "resource_name"="letsencrypt" "resource_namespace"="" "resource_version"="v1"

In step 6 and 7, no matter updating content of existing secret or changing secret name to another one, the clusterissuer won't change the acme account.

Given the secret content of privateKeySecretRef changed to another account's secret key, the clusterissuer should change the acme account accordingly.