Restoring the Undercloud

Restoring the Undercloud

The following restore process assumes you are recovering from a failed Undercloud node where you have to reinstall it from scratch. It assumes that the hardware layout is the same, and the hostname and Undercloud settings of the machine will be the same as well. Once the machine is installed and is in a clean state, re-enable all the subscriptions/repositories needed to install and run TripleO.

Note that unless specified, all commands should run as the stack user.

NTP service

OpenStack services are time sensitive, users need to be sure their environment have the time synchronized correctly before proceeding with any backup task.

By default, both Undercloud and Overcloud should have configured correctly the NTP service as there are parameters specifically defined to manage this service.

The user is responsible to ensure that the Undercloud restore is consistent in time. For example, a user installs the Undercloud at the time ‘m’, then they deploy the Undercloud and the Overcloud at the time ‘n’, and they create an Undercloud backup at the time ‘o’. When the user restore the Undercloud it needs to be sure is restored at a time later than ‘o’. So, before and after restoring the Undercloud node is important to have all the deployment with the time updated and synchronized correctly.

In case this is done manually, execute:

sudo yum install -y ntp
sudo chkconfig ntpd on
sudo service ntpd stop
sudo ntpdate pool.ntp.org
sudo service ntpd restart

After ensuring the environment have the time synchronized correctly you can continue with the restore tasks.

Downloading automated Undercloud backups

If the user has executed the Undercloud backup from the TripleO CLI, it will need to download it to a local folder and from there execute the restore steps.

# From the Undercloud
source stackrc
mkdir /var/tmp/test_bk_down
cd /var/tmp/test_bk_down
openstack container save undercloud-backups

Now, in the restore_uc_backup folder there must be a file with the following naming convention UC-backup-<timestamp>.tar.

After getting the backup file and unzipping it in any selected folder, the user can proceed with the Undercloud restore.

The following is an example of how to extract the Undercloud backup content:

sudo tar -xvf /var/tmp/test_bk_down/UC-backup-*.tar -C /var/tmp/test_bk_down || true

There, the user will have a tar file with the content of the file system backup and another gz file with the content of the database backup.

The user can proceed to unzip the database and filesystem backup by executing:

sudo gunzip /var/tmp/test_bk_down/*.gz -c > /var/tmp/test_bk_down/all-databases.sql
sudo tar -xvf /var/tmp/test_bk_down/filesystem-*.tar -C /var/tmp/test_bk_down

Restoring a backup of your Undercloud on a Fresh Machine

Assuming that the user has a fresh installed Undercloud node, the user is able to log in as the stack user, and have the Backup restored in the folder /var/tmp/test_bk_down, follow the next steps.

Syncronize the stack home directory, haproxy configuration, certificates and hieradata with the backup content:

sudo rsync -a /var/tmp/test_bk_down/home/stack/ /home/stack
sudo rsync -a /var/tmp/test_bk_down/etc/haproxy/ /etc/haproxy/
sudo rsync -a /var/tmp/test_bk_down/etc/pki/instack-certs/ /etc/pki/instack-certs/
sudo mkdir -p /etc/puppet/hieradata/
sudo rsync -a /var/tmp/test_bk_down/etc/puppet/hieradata/ /etc/puppet/hieradata/
sudo rsync -a /var/tmp/test_bk_down/srv/node/ /srv/node/
sudo rsync -a /var/tmp/test_bk_down/var/lib/glance/ /var/lib/glance/

The Keystone configuration files need to be synchronized before reinstalling the Undercloud node. This is needed because we need to have the same keys in the folders credential-keys and fernet-keys so they don’t get regenerated when running the puppet Undercloud configuration. Take into account that the package openstack-keystone needs to be installed before synchronizing its configuration data:

sudo rsync -a /var/tmp/test_bk_down/etc/keystone/ /etc/keystone/

If the user is using SSL, you need to refresh the CA certificate:

sudo mkdir -p /etc/pki/instack-certs || true
sudo cp /home/stack/undercloud.pem /etc/pki/instack-certs
sudo cp /home/stack/cacert.pem /etc/pki/ca-trust/source/anchors/
sudo cp /home/stack/overcloud-cacert.pem /etc/pki/ca-trust/source/anchors/
sudo semanage fcontext -a -t etc_t "/etc/pki/instack-certs(/.*)?"
sudo restorecon -R /etc/pki/instack-certs
sudo update-ca-trust extract

Install the required packages with:

sudo yum install -y mariadb mariadb-server python-tripleoclient

If you are using Pike and Ceph will be used in the Overcloud, install ceph-ansible on the Undercloud:

sudo yum install -y ceph-ansible

Restart MySQL:

sudo systemctl restart mariadb

Allow restore big dump DB files:

mysql -uroot -e"set global max_allowed_packet = 1073741824;"

Restore the DB backup:

mysql -u root < /var/tmp/test_bk_down/all-databases.sql

Restart Mariadb to refresh the permissions from the backup file:

sudo systemctl restart mariadb

Register the root password from the configuration file and clean the DB password to be able to reinstall the Undercloud:

oldpassword=$(sudo cat /var/tmp/test_bk_down/root/.my.cnf | grep -m1 password | cut -d'=' -f2 | tr -d "'")
mysqladmin -u root -p$oldpassword password ''

Remove old user permisology if it exists, replace <node> with the host related to each user.

mysql -e 'select host, user, password from mysql.user;'
for i in ceilometer glance heat ironic keystone neutron nova mistral zaqar;do mysql -e "drop user $i@<node>" || true ;done
mysql -e 'flush privileges'

We have to now install the swift and glance base packages, and then restore their data:

sudo yum install -y openstack-glance openstack-swift
# Restore data from the Backup to: srv/node and var/lib/glance/images
# Confirm data is owned by correct user
sudo chown -R swift: /srv/node
sudo chown -R glance: /var/lib/glance/images

Finally, we rerun the Undercloud installation from the stack user, making sure to run it in the stack user home dir:

# Double check hostname is correctly set in /etc/hosts
openstack undercloud install

Reconnect the restored Undercloud to the Overcloud

Having completed the steps above, the Undercloud can be expected to automatically restore its connection to the Overcloud. The nodes will continue to poll Orchestration (heat) for pending tasks, using a simple HTTP request issued every few seconds.

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