diff --git a/centos/5/Dockerfile b/centos/5/Dockerfile
index a78934f..1adedb3 100644
--- a/centos/5/Dockerfile
+++ b/centos/5/Dockerfile
@@ -6,6 +6,7 @@ RUN chmod +x /tini
 
 RUN set -x \
     && yum install -y ruby-devel rubygems gcc make rpmdevtools \
+    && gem install json -v 1.8.3 \
     && gem install fpm -v 1.4.0 \
     && yum clean all \
     && mkdir /src
diff --git a/centos/6/Dockerfile b/centos/6/Dockerfile
index 64f7511..e557624 100644
--- a/centos/6/Dockerfile
+++ b/centos/6/Dockerfile
@@ -6,6 +6,7 @@ RUN chmod +x /tini
 
 RUN set -x \
     && yum install -y ruby-devel rubygems gcc make rpmdevtools \
+    && gem install json -v 1.8.3 \
     && gem install fpm -v 1.4.0 \
     && yum clean all \
     && mkdir /src