This document is a step by step procedure for upgrading from Scylla 3.x.y to Scylla 3.x.z.
This guide covers upgrading Scylla from the following versions: 3.x.y to Scylla version 3.x.z on the following platform:
Debian 8
Note
Ubuntu 14 is not supported in the following versions of Scylla Open Source: 3.1.x and 3.0.11 and above
Warning
If and only if you installed a fresh Scylla 3.1.0, you must add the following line to scylla.yaml of each node before upgrading to a later Scylla version:
enable_3_1_0_compatibility_mode: true
This is not relevant if your cluster was upgraded to 3.1.0 from an older version, or you are upgrading from or to any other Scylla release.
Note
Execute the following commands one node at the time, moving to the next node only after the upgrade procedure completed successfully.
Warning
If you are using CDC and upgrading Scylla 4.3 to 4.4, please review the API updates in querying CDC streams and CDC stream generations. In particular, you should update applications that use CDC according to CDC Upgrade notes before upgrading the cluster to 4.4.
If you are using CDC and upgrading from pre 4.3 version to 4.3, note the upgrading from experimental CDC.
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
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.
sudo cp -a /etc/scylla/scylla.yaml /etc/scylla/scylla.yaml.backup-3.x.z
sudo service scylla-server stop
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:
Update the Scylla deb repo to 3.x
Install
sudo apt-get update
sudo apt-get dist-upgrade scylla
Answer ‘y’ to the first two questions.
sudo service scylla-server start
Check cluster status with nodetool status and make sure all nodes, including the one you just upgraded, are in UN status.
Use curl -X GET "http://localhost:10000/storage_service/scylla_release_version" to check scylla version.
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.
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.
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.
nodetool drain
sudo service scylla-server stop
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.
sudo rm -rf /etc/scylla/scylla.yaml
sudo cp -a /etc/scylla/scylla.yaml.backup-3.x.z /etc/scylla/scylla.yaml
sudo service scylla-server start
Check upgrade instruction above for validation. Once you are sure the node rollback is successful, move to the next node in the cluster.