Openshift SSO with Gitlab

Configure Openshift Cluster to use Gitlab as a user backend for login with oauth2 and SSO.

Parts of the Openshift series

• Part1: Install Opeshift
• Part2: How to Enable Auto Approval of CSR in Openshift v3.11
• Part3: Add new workers to Openshift cluster
• Part4: Chane the certificates of the Openshift cluster
• Part5: LDAP authentication for Openshift
• Part6: Keycloak SSO authentication for Openshift
• Part7: Gitlab SSO authentication for Openshift
• Part8a: Ceph persistent storage for Openshift
• Part8b: vSphere persistent storage for Openshift
• Part9: Helm on Openshift
• Part10: Tillerless Helm on Openshift
• Part11: Use external docker registry on Openshift
• Part12: Secondary router on Openshift
• Part13a: Use Letsencrypt on Openshift
• Part13b: Install cert-managger on Openshift
• Part14: Create Openshift operators
• Part15: Convert docker-compose file to Opeshift
• Part16a: Opeshift elasticsearch search-guard error
• Part16b: Openshift: Log4Shell - Remote Code Execution (CVE-2021-44228) (CVE-2021-4104)

With Ansible-openshift you can not change the authetication method after Install !! If you installed the cluster with htpasswd, then change to LDAP the playbook trys to add a second authentication methot for the config. It is forbidden to add a second type of identity provider in the version 3.11 of Ansible-openshift. To solve this problem we must change the configuration manually.

Environment

192.168.1.40    deployer
192.168.1.41    openshift01 # master node
192.168.1.42    openshift02 # infra node
192.168.1.43    openshift03 # worker node

Configuration Gitlab

Login to Gitlab and create client for the app:

Configurate The cluster

# on all openshift hosts
nano /etc/origin/master/master-config.yaml
...
  identityProviders:
  - name: gitlabsso
    challenge: true
    login: true
    mappingMethod: claim
    provider:
      apiVersion: v1
      kind: GitLabIdentityProvider
      legacy: true
      clientID: 7305abce637a123654a2c9dd4f8caec1156a1bc41cd80be4db0f14253fe24e58
      clientSecret: 2d5aebe7831c99383d876cc235febb401906263de748a29b03b058f62f15c2f7
      url: https://gitlab.devopstales.intra/
  - challenge: true

Reconfigurate the cluster

# on all openshift hosts
master-restart api
master-restart controllers