Upgrade Guide - Scylla Enterprise 2019.x.y to 2019.x.z for Red Hat Enterprise 7 or CentOS 7

This document is a step by step procedure for upgrading from Scylla Enterprise 2019.x.y to 2019.x.z.

Applicable versions

This guide covers upgrading Scylla Enterprise from the following versions: 2019.x.y to 2019.x.z, on the following platforms:

  • Red Hat Enterprise Linux, version 7 and later

  • CentOS, version 7 and later

  • No longer provide packages for Fedora

Upgrade Procedure

Note

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

Note

If any of your instances are running Scylla Enterprise 2019.1.6 or earlier, and one of your Scylla nodes is up for more than a year, you might have been exposed to issue #6063. One way to check this is by comparing Generation No (from nodetool gossipinfo output) with the current time in Epoch format (date +%s), and check if the difference is higher than one year (31536000 seconds). See scylla-check-gossiper-generation for a script to do just that.

If this is the case, do not initiate the upgrade process before consulting with Scylla Support for further instructions.

Note

Scylla Enterprise 2019.1.6 added a new configuration to restrict the memory usage cartesian product IN queries. If you are using IN in SELECT operations and hitting a “cartesian product size … is greater than maximum” error, you can either update the query (recommended) or bypass the warning temporarily by adding the following parameters to scylla.yaml:

  • max_clustering_key_restrictions_per_query: 1000

  • max_partition_key_restrictions_per_query: 1000

The higher the values, the more likely you will hit an out of memory issue.

Note

Scylla Enterprise 2019.1.8 added a new configuration to restrict the memory usage of reverse queries. If you are using reverse queries and hitting an error “Aborting reverse partition read because partition … is larger than the maximum safe size of … for reversible partitions” see the reverse queries FAQ section.

A Scylla upgrade is a rolling procedure that does not require a full cluster shutdown. For each of the nodes in the cluster, serially (i.e. one at a time), 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 2019.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-2019.x.z

Stop Scylla

sudo systemctl stop scylla-server

Download and install the new release

Before upgrading, check what version you are running now using rpm -qa | grep scylla-server. You should use the same version in case you want to rollback the upgrade. If you are not running a 2019.x.y version, stop right here! This guide only covers 2019.x.y to 2019.x.z upgrades.

To upgrade:

  1. Update the Scylla Enterprise RPM repo to 2019.x

  2. install

sudo yum update scylla\* -y

Start the node

sudo systemctl start scylla-server

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. Use journalctl _COMM=scylla to check there are no new errors in the log.

  4. Check again after two 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 Enterprise release 2019.x.z to 2019.x.y. Apply this procedure if an upgrade from 2019.x.y to 2019.x.z failed before completing on all nodes. Use this procedure only for nodes you upgraded to 2019.x.z

Scylla rollback is a rolling procedure that does not require a full cluster shutdown. For each of the nodes rollback to 2019.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 systemctl stop scylla-server

Downgrade to previous release

  1. Install

sudo yum downgrade scylla\*-2019.x.y -y

Restore the configuration file

sudo rm -rf /etc/scylla/scylla.yaml
sudo cp -a /etc/scylla/scylla.yaml.backup-2019.x.z /etc/scylla/scylla.yaml

Start the node

sudo systemctl start scylla-server

Validate

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