I have installed Gitlab CE using Helm, but our AD users can't login to the platform. The following error is shown in the login UI: Could not authenticate you from Ldapmain because "Invalid credentials for userX" Invalid credentials for user (but credentials are ok!)

Installation:

helm upgrade --install gitlab gitlab/gitlab --namespace my-ns --tiller-namespace tiller-ns  --timeout 600 --set global.edition=ce --set global.hosts.domain=example.com --set global.hosts.externalIP=<ExternalIPAddressAllocatedToTheNGINXIngressControllerLBService> --set nginx-ingress.enabled=false --set global.ingress.class=mynginx-ic --set certmanager.install=false --set global.ingress.configureCertmanager=false --set gitlab-runner.install=false --set prometheus.install=false --set registry.enabled=false --set gitlab.gitaly.persistence.enabled=false --set postgresql.persistence.enabled=false --set redis.persistence.enabled=false --set minio.persistence.enabled=false --set global.appConfig.ldap.servers.main.label='LDAP' --set global.appConfig.ldap.servers.main.host=<IPAddressOfMyDomainController> --set global.appConfig.ldap.servers.main.port='389' --set global.appConfig.ldap.servers.main.uid='sAMAccountName' --set global.appConfig.ldap.servers.main.bind_dn='CN=testuser,OU=sampleOU3,OU=sampleOU2,OU=sampleOU1,DC=example,DC=com' --set global.appConfig.ldap.servers.main.password.secret='gitlab-ldap-secret' --set global.appConfig.ldap.servers.main.password.key='password' 

Notes:
-I have installed previously my own NGINX Ingress Controller separately:

helm install stable/nginx-ingress --name nginx-ingress --namespace my-ns --tiller-namespace tiller-ns --set controller.ingressClass=mynginx-ic  

-I have previously created a secret with the password for the user configured as bind_dn ('CN=testuser,OU=sampleOU3,OU=sampleOU2,OU=sampleOU1,DC=example,DC=com'). The password is encoded using base64, as indicated in the documentation

File: gitlab-ldap-secret.yaml

apiVersion: v1  
kind: Secret  
metadata:  
 name: gitlab-ldap-secret  
data:  
 password: encodedpass-blablabla 

-Instead of providing all these parameters in the commandline during the chart installation, I have tried just configuring everything in the various values.yaml that this Gitlab Helm chart provides, but it just seemed easier to document here this way, for reproduction purposes.

-I have tried adding these parameters, no luck:

--set global.appConfig.ldap.servers.main.encryption='plain'  
--set global.appConfig.ldap.servers.main.base='OU=sampleOU1,DC=example,DC=com'  

-To make it even simpler, we are not considering persistency for any component. That is why, these are all set to false:

--set gitlab.gitaly.persistence.enabled=false  
--set postgresql.persistence.enabled=false  
--set redis.persistence.enabled=false  
--set minio.persistence.enabled=false   

*I do need persistency, but let's just focus on LDAP authentication this time, which is my main issue at the moment.

-I have checked with my sysadmin, and we use plain 389 in Active Directory. No encryption

My environment

kubectl.exe version  
Client Version: version.Info{Major:"1", Minor:"15", GitVersion:"v1.15.1", GitCommit:"4485c6f18cee9a5d3c3b4e523bd27972b1b53892", GitTreeState:"clean", BuildDate:"2019-07-18T09:18:22Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"windows/amd64"}  
Server Version: version.Info{Major:"1", Minor:"15", GitVersion:"v1.15.1", GitCommit:"4485c6f18cee9a5d3c3b4e523bd27972b1b53892", GitTreeState:"clean", BuildDate:"2019-07-18T09:09:21Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}  

helm version  
Client: &version.Version{SemVer:"v2.14.3", GitCommit:"0e7f3b6637f7af8fcfddb3d2941fcc7cbebb0085", GitTreeState:"clean"}  
Server: &version.Version{SemVer:"v2.14.3", GitCommit:"0e7f3b6637f7af8fcfddb3d2941fcc7cbebb0085", GitTreeState:"clean"}  

helm ls --tiller-namespace tiller-ns  
NAME                    REVISION        UPDATED                         STATUS          CHART                   APP VERSION     NAMESPACE
gitlab                  1               Tue Oct 29 18:16:06 2019        DEPLOYED        gitlab-2.3.7            12.3.5          my-ns

kubectl.exe get nodes
NAME                                    STATUS   ROLES    AGE     VERSION
kubernetes01.example.com                Ready    master   102d    v1.15.1
kubernetes02.example.com                Ready    <none>   7h16m   v1.15.1
kubernetes03.example.com                Ready    <none>   102d    v1.15.1
kubernetes04.example.com                Ready    <none>   11d     v1.15.1

After installing this chart, everything seems to work fine:

kubectl.exe get pods
NAME                                                   READY   STATUS      RESTARTS   AGE
gitlab-gitaly-0                                        1/1     Running     0          65m
gitlab-gitlab-exporter-5b649bfbb-5pn7q                 1/1     Running     0          65m
gitlab-gitlab-shell-7d9497fcd7-h5478                   1/1     Running     0          65m
gitlab-gitlab-shell-7d9497fcd7-jvt9p                   1/1     Running     0          64m
gitlab-migrations.1-gf8jr                              0/1     Completed   0          65m
gitlab-minio-cb5945f79-kztmj                           1/1     Running     0          65m
gitlab-minio-create-buckets.1-d2bh5                    0/1     Completed   0          65m
gitlab-postgresql-685b68b4d7-ns2rw                     2/2     Running     0          65m
gitlab-redis-5cb5c8b4c6-jtfnr                          2/2     Running     0          65m
gitlab-sidekiq-all-in-1-5b997fdffd-n5cj2               1/1     Running     0          65m
gitlab-task-runner-5777748f59-gkf9v                    1/1     Running     0          65m
gitlab-unicorn-764f6548d5-fmggl                        2/2     Running     0          65m
gitlab-unicorn-764f6548d5-pqcm9                        2/2     Running     0          64m

Now, if I try to login with a LDAP user, I get the error mentioned before. If I go inside the unicorn pod, I can see the following messages in the /var/log/gitlab/production.log: Production.log

What am I missing? Do I need to configure anything else? I have configured all the parameters for LDAP Authentication mentioned here but still I'm having trouble trying to authenticate.

Sorry, but I am new with Gitlab and all its internal components. I can't seem to find where to edit this file for example: /etc/gitlab/gitlab.rb (in which pod should I enter? I literally entered each one of them, and did not find this configuration file). Also, I noticed some of the documentation says that some diagnostics tools can be executed such as gitlab-rake gitlab:ldap:check, or utilities such as gitlab-ctl reconfigure, but again.... where to run these?? On the unicorn pod? gitlab-shell? I noticed various Gitlab documentation pages reference to some of these tools to troubleshoot incidents, but I don't think this chart follows the same architecture.

I have looked this post for example, because it seems the same issue, but I can't find /etc/gitlab/gitlab.rb

Any help will be much appreciated. It's been a couple of weeks since I've been dealing with this issue.