diff --git a/dockerfiles/alpine-jenkins.txt b/dockerfiles/alpine-jenkins.txt
index 7e98ff3..6f678ac 100644
--- a/dockerfiles/alpine-jenkins.txt
+++ b/dockerfiles/alpine-jenkins.txt
@@ -13,6 +13,6 @@ RUN wget -q -O- http://ftp.cuhk.edu.hk/pub/packages/apache.org/tomcat/tomcat-9/v
 RUN rm -rf /opt/tomcat/webapps/ROOT
 RUN wget -q -O /opt/tomcat/webapps/jenkins.war http://mirrors.jenkins.io/war-stable/latest/jenkins.war
 ENV JAVA_HOME="/usr"
-ENV JAVA_OPTS="-Djava.awt.headless=true"
+ENV JAVA_OPTS="-Djava.awt.headless=true -Xmx2g -Dhudson.DNSMultiCast.disabled=true -Duser.timezone=Asia/Hong_Kong"
 EXPOSE 8080
 CMD ["/opt/tomcat/bin/catalina.sh", "run"]