Upgrade Guide - Scylla 3.x.y to 3.x.z for Debian 8

This document is a step by step procedure for upgrading from Scylla 3.x.y to Scylla 3.x.z.

Applicable versions

This guide covers upgrading Scylla from the following versions: 3.x.y to Scylla version 3.x.z on the following platform:

  • Debian 8

Upgrade Procedure

Note

Execute the following commands one node at the time, moving to the next node only after the upgrade procedure completed successfully.

A Scylla upgrade is a rolling procedure which does not require full cluster shutdown. For each of the nodes in the cluster, you will:

  • Drain node and backup the data
  • Check your current release
  • Backup configuration file
  • Stop Scylla
  • Download and install new Scylla packages
  • Start Scylla
  • Validate that the upgrade was successful

Apply the following procedure serially on each node. Do not move to the next node before validating the node is up and running with the new version.

During the rolling upgrade it is highly recommended:

  • Not to use new 3.x.z features
  • Not to run administration functions, like repairs, refresh, rebuild or add or remove nodes
  • Not to apply schema changes

Upgrade steps

Drain node and backup the data

Before any major procedure, like an upgrade, it is recommended to backup all the data to an external device. In Scylla, backup is done using the nodetool snapshot command. For each node in the cluster, run the following command:

nodetool drain
nodetool snapshot

Take note of the directory name that nodetool gives you, and copy all the directories having this name under /var/lib/scylla to a backup device.

When the upgrade is complete (all nodes), the snapshot should be removed by nodetool clearsnapshot -t <snapshot>, or you risk running out of space.

Backup configuration file

sudo cp -a /etc/scylla/scylla.yaml /etc/scylla/scylla.yaml.backup-3.x.z

Gracefully stop the node

sudo service scylla-server stop

Download and install the new release

Before upgrading, check what version you are running now using dpkg -s scylla-server. You should use the same version in case you want to rollback the upgrade. If you are not running a 3.x.y version, stop right here! This guide only covers 3.x.y to 3.x.z upgrades.

To upgrade:

  1. Update the Scylla deb repo to 3.x
  2. Install
sudo apt-get update
sudo apt-get dist-upgrade scylla

Answer ‘y’ to the first two questions.

Start the node

sudo service scylla-server start

Validate

  1. Check cluster status with nodetool status and make sure all nodes, including the one you just upgraded, are in UN status.
  2. Use curl -X GET "http://localhost:10000/storage_service/scylla_release_version" to check scylla version.
  3. Check scylla-server log (check /var/log/upstart/scylla-server.log for Ubuntu 14.04, execute journalctl _COMM=scylla for Ubuntu 16.04 and Ubuntu 18.04) and /var/log/syslog to validate there are no errors.
  4. Check again after 2 minutes, to validate no new issues are introduced.

Once you are sure the node upgrade is successful, move to the next node in the cluster.

Rollback Procedure

Note

Execute the following commands one node at the time, moving to the next node only after the rollback procedure completed successfully.

The following procedure describes a rollback from Scylla release 3.x.z to 3.x.y. Apply this procedure if an upgrade from 3.x.y to 3.x.z failed before completing on all nodes. Use this procedure only for nodes you upgraded to 3.x.z

Scylla rollback is a rolling procedure which does not require full cluster shutdown. For each of the nodes rollback to 3.x.y, you will:

  • Drain the node and stop Scylla
  • Downgrade to previous release
  • Restore the configuration file
  • Restart Scylla
  • Validate the rollback success

Apply the following procedure serially on each node. Do not move to the next node before validating the node is up and running with the new version.

Rollback steps

Gracefully shutdown Scylla

nodetool drain
sudo service scylla-server stop

Downgrade to previous release

  1. install
sudo apt-get install scylla=3.x.y\* scylla-server=3.x.y\* scylla-jmx=3.x.y\* scylla-tools=3.x.y\* scylla-tools-core=3.x.y\* scylla-kernel-conf=3.x.y\* scylla-conf=3.x.y\*

Answer ‘y’ to the first two questions.

Restore the configuration file

sudo rm -rf /etc/scylla/scylla.yaml
sudo cp -a /etc/scylla/scylla.yaml.backup-3.x.z /etc/scylla/scylla.yaml

Start the node

sudo service scylla-server start

Validate

Check upgrade instruction above for validation. Once you are sure the node rollback is successful, move to the next node in the cluster.