Document URL: 
https://docs.openshift.com/container-platform/3.3/install_config/downgrade.html

Section Number and Name: 

Describe the issue: 
The containerized etcd use different service name and systemd configure file. so it is better to adjust the document for it.

Suggestions for improvement: 

A single containerized etcd downgrade steps is as following. 

1) systemctl stop etcd_container
2) copy backup etcd data file
# ETCD_DIR=/var/lib/etcd/
# mv $ETCD_DIR /var/lib/etcd.orig
# cp -Rp /var/lib/origin/etcd-backup-<timestamp>/ $ETCD_DIR
# chcon -R --reference /var/lib/etcd.orig/ $ETCD_DIR
# chown -R etcd:etcd $ETCD_DIR

3) Modify /etc/systemd/system/etcd_container.service;
  3.1)  set correct image version
  3.2)  add --force-new-cluster
  For example
   ExecStart=/usr/bin/docker run --name etcd_container --rm -v /var/lib/etcd:/var/lib/etcd:z -v /etc/etcd:/etc/etcd:z --env-file=/etc/etcd/etcd.conf --net=host --entrypoint=/usr/bin/etcd registry.access.redhat.com/rhel7/etcd3:3.0.14
   ExecStart=/usr/bin/docker run --name etcd_container --rm -v /var/lib/etcd:/var/lib/etcd:z -v /etc/etcd:/etc/etcd:z --env-file=/etc/etcd/etcd.conf --net=host --entrypoint=/usr/bin/etcd registry.access.redhat.com/rhel7/etcd --force-new-cluster
4) systemctl daemon-reload
5) systemctl start etcd_container
6) remove the --force-new-cluster in /etc/systemd/system/etcd_container.service
   
7)  systemctl daemon-reload; systemctl restart etcd_container


Additional information: