show how to uninstall jenkins if there are issues upgrading
diff --git a/tools/jenkins/jenkins_home/build_jenkins.sh b/tools/jenkins/jenkins_home/build_jenkins.sh
index 9a32a0a..7d68679 100755
--- a/tools/jenkins/jenkins_home/build_jenkins.sh
+++ b/tools/jenkins/jenkins_home/build_jenkins.sh
@@ -25,6 +25,13 @@
wget -q -O - http://pkg.jenkins-ci.org/debian/jenkins-ci.org.key | sudo apt-key add -
apt-get update
+
+# Clean out old jenkins - useful if you are having issues upgrading
+CLEAN_JENKINS=${CLEAN_JENKINS:-no}
+if [ "$CLEAN_JENKINS" = "yes" ] then;
+ apt-get remove jenkins jenkins-common
+fi
+
# Install software
DEPS="jenkins cloud-utils"
apt-get install -y --force-yes $DEPS