Authentik
Authentik is deployed as the central identity provider, providing OIDC and LDAP authentication for services in the cluster.
Components
- Authentik Server — Helm chart deployment (
apps/templates/authentik-helm.yaml) - PostgreSQL — CloudNativePG cluster (
postgresql-cluster.yaml) - Secrets — ExternalSecrets from Vault (
external-secret.yaml) - Blueprints — Auto-configured providers:
blueprint-ldap.yaml— LDAP provider (base DN:DC=ldap,DC=goauthentik,DC=io)blueprint-mail-oidc.yaml— OAuth2/OIDC provider for Stalwart mailblueprint-vault-oidc.yaml— OIDC provider for Vault
LDAP Outpost
The LDAP outpost exposes Authentik's user directory over LDAP. It is used by:
- SOGo-mail (in-cluster) — connects via
ak-outpost-ldap-outpost.authentik.svc.cluster.local:3389 - Stalwart (NixOS, external) — connects via
ldap.rubenhensen.nl:389
NodePort Service
The outpost is exposed externally via a NodePort service (ldap-outpost-lb.yaml):
- LDAP:
389 → 3389(NodePort30389) - LDAPS:
636 → 6636(NodePort30636)
The router port-forwards 389 → 30389 on the cluster node to make it reachable at ldap.rubenhensen.nl.
Important: The pod selector is app.kubernetes.io/name: authentik-outpost-ldap (set by Authentik's outpost controller, not the outpost name).
MicroK8s CA Certificate Fix
Authentik's outpost controller needs to talk to the Kubernetes API to deploy the LDAP outpost pod. This fails on MicroK8s because the default CA certificate is missing the keyUsage extension, which Python 3.13+ enforces strictly.
Error:
SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed:
CA cert does not include key usage extension (_ssl.c:1081)
Root cause: https://github.com/canonical/microk8s/issues/4864
Fix applied (2026-03-21): Regenerated the MicroK8s CA certificate with the keyUsage extension using the script from the issue above:
#!/bin/bash
set -euo pipefail
cert_workspace="$HOME/fixed-certs"
mkdir -p "$cert_workspace"
cd "$cert_workspace"
# Generate new CA key
openssl genrsa -out ca.key 2048
# Generate CA cert WITH keyUsage extension
openssl req -x509 -new -nodes -key ca.key -sha256 -days 3650 \
-out ca.crt \
-addext "keyUsage=critical,digitalSignature,keyCertSign" \
-subj "/CN=microk8s-ca"
# Verify the certificate has the extension
openssl x509 -in ca.crt -text -noout | grep -A 1 "Key Usage"
# Rotate the cluster CA
microk8s refresh-certs "$cert_workspace"
# Regenerate kubeconfig
mkdir -p ~/.kube
microk8s config > ~/.kube/config
Note: This must be re-applied after MicroK8s upgrades or cert rotations, as MicroK8s may regenerate the CA without the extension. The fix needs to run on every node in the cluster.