diff --git a/Dockerfile b/Dockerfile
index 2445d31..a8962f7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,12 +5,10 @@ COPY requirements.txt .
 ARG VENV=/opt/netbox-sync/venv
 
 # Install dependencies
-RUN apt-get update && \
-    rm -rf /var/lib/apt/lists/* && \
-    python3 -m venv $VENV && \
+RUN python3 -m venv $VENV && \
     $VENV/bin/python3 -m pip install --upgrade pip && \
     $VENV/bin/pip install -r requirements.txt && \
-    $VENV/bin/pip install --upgrade vcf-sdk && \
+    $VENV/bin/pip install vmware-vcenter==9.1.1.0 && \
     find $VENV -type d -name "__pycache__" -print0 | xargs -0 -n1 rm -rf
 
 FROM python:3.14-slim AS netbox-sync
@@ -25,11 +23,14 @@ RUN groupadd --gid 1000 netbox-sync && \
     useradd --uid 1000 --gid netbox-sync --shell /bin/sh \
     --no-create-home --system netbox-sync
 
-USER netbox-sync
-
-# Prepare the application
+# Prepare the application: the code belongs to root and is read-only for the
+# service user; only the cache directory is writable (group 0 as well, so an
+# arbitrary uid in group 0 can use it)
 WORKDIR /app
-COPY --chown=netbox-sync:netbox-sync . .
+COPY . .
+RUN mkdir -p /app/cache && chown netbox-sync:0 /app/cache && chmod 0770 /app/cache
+
+USER netbox-sync
 
 # Use virtual env packages and allow timezone setup
 ENV PATH=$VENV/bin:$PATH