diff --git a/Dockerfile b/Dockerfile
index f701e5c2..068cb1ad 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:3.19.1
+FROM alpine:3.23
 
 ADD target/bundle /lrsql
 ADD .java_modules /lrsql/.java_modules
@@ -8,10 +8,10 @@ RUN apk update \
         && apk upgrade \
         && apk add ca-certificates \
         && update-ca-certificates \
-        && apk add --no-cache openjdk11 \
+        && apk add --no-cache openjdk25 \
         && mkdir -p /lrsql/runtimes \
         && jlink --output /lrsql/runtimes/linux/ --add-modules $(cat /lrsql/.java_modules) \
-        && apk del openjdk11 \
+        && apk del openjdk25 \
         && rm -rf /var/cache/apk/*
 
 # delete bench utils for leaner container
diff --git a/doc/docker.md b/doc/docker.md
index 4fc3b6e1..08f77609 100644
--- a/doc/docker.md
+++ b/doc/docker.md
@@ -101,4 +101,66 @@ CMD ["/lrsql/bin/run_postgres.sh"]
 
 The resulting image will use the provided configuration file and run Postgres. See [Getting Started](startup.md) for more configuration information.
 
+### Building the Docker Image
+
+To build the Docker image locally from source:
+
+#### Prerequisites
+
+- Java 25+ (must match the JDK used in the Dockerfile)
+- [Clojure CLI tools](https://clojure.org/guides/install_clojure)
+- Docker
+- `make`
+
+#### Steps
+
+1. **Download the Admin UI assets:**
+
+``` shell
+make resources/public/admin
+```
+
+2. **Build the uberjar:**
+
+``` shell
+clojure -X:build uber
+```
+
+This creates `target/bundle/lrsql.jar`.
+
+3. **Assemble the bundle directory:**
+
+The Dockerfile expects a `target/bundle` directory containing the jar, run scripts and config. You can build the full bundle with:
+
+``` shell
+make bundle
+```
+
+Or assemble a minimal bundle manually:
+
+``` shell
+mkdir -p target/bundle/config
+cp -r bin target/bundle/bin
+cp resources/lrsql/config/lrsql.json.example target/bundle/config/
+cp resources/lrsql/config/authority.json.template target/bundle/config/authority.json.template.example
+cp -r resources/public/admin target/bundle/admin
+```
+
+4. **Build the Docker image:**
+
+``` shell
+docker build -t lrsql .
+```
+
+5. **Run it:**
+
+``` shell
+docker run -d -p 8080:8080 \
+    -e LRSQL_API_KEY_DEFAULT=my_key \
+    -e LRSQL_API_SECRET_DEFAULT=my_secret \
+    -e LRSQL_ADMIN_USER_DEFAULT=my_username \
+    -e LRSQL_ADMIN_PASS_DEFAULT=my_password \
+    lrsql
+```
+
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