diff --git a/.gitignore b/.gitignore
index 5fbadf7962..e3add1fc02 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,7 @@
 build/
 **/build/
+build/certs/nginx-repo.key
+build/certs/nginx-repo.crt
 bin/
 whitesource/
 .vscode/
diff --git a/Makefile b/Makefile
index 0eefceef74..67d27e6096 100644
--- a/Makefile
+++ b/Makefile
@@ -23,8 +23,8 @@ DATE = $(shell date +%F_%H-%M-%S)
 # | suse             | sles12sp5, sle15              |                                                                |
 # | freebsd          |                               | Not supported                                                  |
 # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
-OS_RELEASE  ?= ubuntu
-OS_VERSION  ?= 22.04
+OS_RELEASE  ?= debian
+OS_VERSION  ?= bullseye-slim
 BASE_IMAGE  = "${CONTAINER_REGISTRY}/${OS_RELEASE}:${OS_VERSION}"
 IMAGE_TAG   = "agent_${OS_RELEASE}_${OS_VERSION}"
 
@@ -83,7 +83,7 @@ show-env: $(addprefix show-var-, $(SHOW_ENV_VARS)) ## Show environment
 all: clean build run ## Compile and run code.
 
 clean: ## Remove build directory
-	rm -rf ./build
+	if [ -d "./build" ]; then find ./build -mindepth 1 ! -path '${CERTS_DIR}/nginx-repo.crt' ! -path '${CERTS_DIR}/nginx-repo.key' -delete; fi
 
 run: ## Run code
 	go run -ldflags=${LDFLAGS} main.go
@@ -252,8 +252,8 @@ image: ## Build agent container image for NGINX Plus, need nginx-repo.crt and ng
 	@echo Building image with $(CONTAINER_CLITOOL); \
 	$(CONTAINER_BUILDENV) $(CONTAINER_CLITOOL) build -t ${IMAGE_TAG} . \
 		--no-cache -f ./scripts/docker/nginx-plus/${OS_RELEASE}/Dockerfile \
-		--secret id=nginx-crt,src=build/nginx-repo.crt \
-		--secret id=nginx-key,src=build/nginx-repo.key \
+		--secret id=nginx-crt,src=${CERTS_DIR}/nginx-repo.crt \
+		--secret id=nginx-key,src=${CERTS_DIR}/nginx-repo.key \
 		--build-arg BASE_IMAGE=${BASE_IMAGE} \
 		--build-arg PACKAGES_REPO=${PACKAGES_REPO} \
 		--build-arg OS_RELEASE=${OS_RELEASE} \
diff --git a/scripts/docker/nginx-plus/debian/Dockerfile b/scripts/docker/nginx-plus/debian/Dockerfile
index bbf3dc1562..3ac1005394 100644
--- a/scripts/docker/nginx-plus/debian/Dockerfile
+++ b/scripts/docker/nginx-plus/debian/Dockerfile
@@ -17,7 +17,7 @@ RUN --mount=type=secret,id=nginx-crt,dst=/nginx-repo.crt \
     && apt-get update \
     && apt-get install --no-install-recommends --no-install-suggests -y \
                         ca-certificates \
-                        gnupg1 \
+                        gnupg \
                         lsb-release \
     && \
     NGINX_GPGKEY=573BFD6B3D8FBC641079A6ABABF5BD827BD9BF62; \
@@ -52,7 +52,10 @@ RUN --mount=type=secret,id=nginx-crt,dst=/nginx-repo.crt \
                         $nginxPackages \
                         curl \
                         gettext-base \
-    && apt-get remove --purge -y lsb-release \
+    && apt-get autoremove --purge -y \
+       gnupg \
+       lsb-release \
+    && rm -rf /root/.gnupg \
     && apt-get remove --purge --auto-remove -y && rm -rf /var/lib/apt/lists/* /etc/apt/sources.list.d/nginx-plus.list \
     && rm -rf /etc/apt/apt.conf.d/90nginx /etc/ssl/nginx