diff --git a/Dockerfile b/Dockerfile
index 1dbf28e..a4941c7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -329,6 +329,25 @@ RUN set -eux; \
     echo 'date.timezone=Asia/Bangkok'; \
   } | tee /usr/local/etc/php/conf.d/core.ini;
 
+# install phpredis
+RUN set -eux; \
+    PHPREDIS_VERSION="2.2.8"; \
+    cd /tmp; \
+    mkdir phpredis; \
+    curl -sL "https://pecl.php.net/get/redis-${PHPREDIS_VERSION}.tgz" -o phpredis.tar.gz; \
+    tar -xzf phpredis.tar.gz -C phpredis --strip-components=1; \
+    cd /tmp/phpredis; \
+    phpize; \
+    ./configure; \
+    make install; \
+    rm -rf /tmp/*
+RUN set -eux; \
+  { \
+    echo '[Core]'; \
+    echo 'session.save_handler = redis'; \
+    echo 'session.save_path = "tcp://valkey:6379"'; \
+  } | tee /usr/local/etc/php/conf.d/session.ini;
+
 # Override stop signal to stop process gracefully
 # https://github.com/php/php-src/blob/17baa87faddc2550def3ae7314236826bc1b1398/sapi/fpm/php-fpm.8.in#L163
 STOPSIGNAL SIGQUIT