okd-configure-htpasswd

idp.sh

#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

# not sure this is still necessary, but can't hurt...
# kick the console pods because they cache oauth metadata (temporary, should not be required)
oc delete pods -n openshift-console --all --force --grace-period=0

# kick the monitoring pods because they cache oauth metadata (temporary, should not be required)
oc delete pods -n openshift-monitoring --all --force --grace-period=0

### The 2 steps below are the 'real' steps you will need in 4.0 ###

# create a secret with htpasswd file data for user 'test' with password 'test'
oc apply -f - <<EOF
apiVersion: v1
kind: Secret
metadata:
  name: htpass-secret
  namespace: openshift-config
data:
  htpasswd: dGVzdDokYXByMSRxa0Zvb203dCRSWFIuNHhTV0lhL3h6dkRRUUFFUG8w
EOF

# configure HTPasswd IDP
oc apply -f - <<EOF
apiVersion: config.openshift.io/v1
kind: OAuth
metadata:
  name: cluster
spec:
  identityProviders:
  - name: htpassidp
    challenge: true
    login: true
    mappingMethod: claim
    type: HTPasswd
    htpasswd:
      fileData:
        name: htpass-secret
EOF

be sure you have exported KUBECONFIG

Shortcut for the secret creation:

kubectl create secret -n openshift-config generic htpasswd-secret --from-literal=htpasswd="$(htpasswd -nb testuser hunter13)" -o yaml --dry-run