diff --git a/Dockerfile b/Dockerfile
index 407d1c6..0b81825 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,18 +1,27 @@
 # syntax=docker/dockerfile:1
 
-FROM focs.ji.sjtu.edu.cn:5000/gitea/runner-images:ubuntu-latest
+FROM focs.ji.sjtu.edu.cn:5000/gitea/runner-images:ubuntu-latest-slim
+
+# use sjtug mirror for faster download
+RUN rm -rf /etc/apt/sources.list.d/* && cat <<EOF > /etc/apt/sources.list
+deb http://mirror.sjtu.edu.cn/debian bookworm main
+deb http://mirror.sjtu.edu.cn/debian-security bookworm-security main
+deb http://mirror.sjtu.edu.cn/debian bookworm-updates main
+EOF
 
 RUN apt-get update && \
-    apt-get install -y sudo && \
+    apt-get install -y sudo python3-minimal pipx git && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/* && \
+    userdel -r node && \
     useradd -u 1000 -ms /bin/bash tt && \
     useradd -u 1001 -ms /bin/bash student && \
     echo "student ALL=(tt) NOPASSWD:/usr/local/bin/joj3" > /etc/sudoers.d/joj
 
 # install joint-teapot
 # TODO: change it to FOCS gitea mirror for deployment
-RUN pip install --no-cache-dir git+https://mirror.ghproxy.com/https://github.com/BoYanZh/Joint-Teapot
+RUN pipx install git+https://mirror.ghproxy.com/https://github.com/BoYanZh/Joint-Teapot && \
+    ln -s /root/.local/bin/joint-teapot /usr/local/bin/joint-teapot
 
 # install joj3 binary
 COPY bin/joj3 /usr/local/bin/
diff --git a/Makefile b/Makefile
index 28862c9..94e0769 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@
 all: build
 
 build:
-	docker build -t focs.ji.sjtu.edu.cn:5000/gitea/runner-images:focs-ubuntu-latest .
+	docker build -t focs.ji.sjtu.edu.cn:5000/gitea/runner-images:focs-ubuntu-latest-slim .
 
 push:
-	docker push focs.ji.sjtu.edu.cn:5000/gitea/runner-images:focs-ubuntu-latest
+	docker push focs.ji.sjtu.edu.cn:5000/gitea/runner-images:focs-ubuntu-latest-slim