Add Dockerfile based on Red Hat UBI (#10958)

See https://connect.redhat.com/zones/containers/container-certification-policy-guide
for details

Co-authored-by: Harshavardhana <harsha@minio.io>

dockerscripts/docker-entrypoint.ubi.sh

@@ -0,0 +1,84 @@
+#!/bin/sh
+#
+# MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# If command starts with an option, prepend minio in UBI container image
+if [ "${1}" != "minio" ]; then
+    if [ -n "${1}" ]; then
+        set -- minio "$@"
+    fi
+fi
+
+## Look for docker secrets at given absolute path or in default documented location.
+docker_secrets_env() {
+    if [ -f "$MINIO_ACCESS_KEY_FILE" ]; then
+        ACCESS_KEY_FILE="$MINIO_ACCESS_KEY_FILE"
+    else
+        ACCESS_KEY_FILE="/run/secrets/$MINIO_ACCESS_KEY_FILE"
+    fi
+    if [ -f "$MINIO_SECRET_KEY_FILE" ]; then
+        SECRET_KEY_FILE="$MINIO_SECRET_KEY_FILE"
+    else
+        SECRET_KEY_FILE="/run/secrets/$MINIO_SECRET_KEY_FILE"
+    fi
+
+    if [ -f "$ACCESS_KEY_FILE" ] && [ -f "$SECRET_KEY_FILE" ]; then
+        if [ -f "$ACCESS_KEY_FILE" ]; then
+            MINIO_ACCESS_KEY="$(cat "$ACCESS_KEY_FILE")"
+            export MINIO_ACCESS_KEY
+        fi
+        if [ -f "$SECRET_KEY_FILE" ]; then
+            MINIO_SECRET_KEY="$(cat "$SECRET_KEY_FILE")"
+            export MINIO_SECRET_KEY
+        fi
+    fi
+}
+
+## Set KMS_MASTER_KEY from docker secrets if provided
+docker_kms_encryption_env() {
+    if [ -f "$MINIO_KMS_MASTER_KEY_FILE" ]; then
+        KMS_MASTER_KEY_FILE="$MINIO_KMS_MASTER_KEY_FILE"
+    else
+        KMS_MASTER_KEY_FILE="/run/secrets/$MINIO_KMS_MASTER_KEY_FILE"
+    fi
+
+    if [ -f "$KMS_MASTER_KEY_FILE" ]; then
+        MINIO_KMS_MASTER_KEY="$(cat "$KMS_MASTER_KEY_FILE")"
+        export MINIO_KMS_MASTER_KEY
+    fi
+}
+
+## Legacy
+## Set SSE_MASTER_KEY from docker secrets if provided
+docker_sse_encryption_env() {
+    SSE_MASTER_KEY_FILE="/run/secrets/$MINIO_SSE_MASTER_KEY_FILE"
+
+    if [ -f "$SSE_MASTER_KEY_FILE" ]; then
+        MINIO_SSE_MASTER_KEY="$(cat "$SSE_MASTER_KEY_FILE")"
+        export MINIO_SSE_MASTER_KEY
+    fi
+}
+
+## Set access env from secrets if necessary.
+docker_secrets_env
+
+## Set kms encryption from secrets if necessary.
+docker_kms_encryption_env
+
+## Set sse encryption from secrets if necessary. Legacy
+docker_sse_encryption_env
+
+exec "$@"