This procedure explains how to add additional clusters to an existing v6.x (or newer) Composite Active/Active configuration.
The example in this procedure adds a new 3-node cluster consisting of nodes db7, db8 and db9 within a service called Tokyo. The existing cluster contains two dataservices, NYC and London, made up of nodes db1, db2, db3 and db4, db5, db6 respectively.
Ensure the new nodes have all the necessary pre-requisites in place, specifically paying attention to the following:
MySQL auto_increment parameters set appropriately on existing and new clusters
All new nodes have full connectivity to the existing nodes and the hosts file contains correct hostnames
All existing nodes have full connectivity to the new nodes and hosts file contains correct hostnames
We need to provision all the new nodes in the new cluster with a backup taken from one node in any of the existing clusters. In this example we are using db6 in the London dataservice as the source for the backup.
Shun and stop the services on the node used for the backup
db6-shell>cctrlcctrl>datasource db6 shuncctrl>replicator db6 offlinecctrl>exitdb6-shell>stopalldb6-shell>sudo service mysqld stop
Next, use whichever method you wish to copy the mysql datafiles from db6 to all the nodes in the new cluster (scp, rsync, xtrabackup etc). Ensure ALL database files are copied.
Once backup copied across, restart the services on db6
db6-shell>sudo service mysqld startdb6-shell>startalldb6-shell>cctrlcctrl>datasource db6 recovercctrl>exit
Ensure all files copied to the target nodes have the correct file ownership
Start mysql on the new nodes
Next we need to change the configuration on the existing hosts to include the configuration of the new cluster.
You need to add a new service block that includes the new nodes and append
the new service to the composite-datasource parameter in the composite
dataservice, all within /etc/tungsten/tungsten.ini
Example of a new service block and composite-datasource change added to existing hosts configuration:
[tokyo] topology=clustered master=db7 members=db7,db8,db9 connectors=db7,db8,db9 [global] topology=composite-multi-master composite-datasources=nyc,london,tokyo
To avoid any differences in configuration, once the changes have been made to the tungsten.ini on the existing hosts, copy this file from one of the nodes to all the nodes in the new cluster.
Ensure start-and-report is
false or not set in the config.
On the 3 new nodes, validate the software:
shell>cd /opt/continuent/software/shell>tungsten-clustering-7.1.4-10tools/tpm validate
This may produce Warnings that the tracking schemas for the existing cluster already exist - this is OK and they can be ignored. Assuming no other unexpected errors are reported, then go ahead and install the software:
shell> tools/tpm installBefore we start the new cluster, we now need to update the existing clusters
Put entire cluster into MAINTENANCE
shell>cctrlcctrl>use {composite-dataservice}cctrl>set policy maintenancecctrl>lsCOORDINATOR[db3:MAINTENANCE:ONLINE] london:COORDINATOR[db4:MAINTENANCE:ONLINE] nyc:COORDINATOR[db3:MAINTENANCE:ONLINE] cctrl>exit
Update the software on each node. This needs to be executed from the software staging directory using the replace-release option as this will ensure the new cross-site dataservices are setup correctly. Update the Primaries first followed by the Replicas, cluster by cluster:
shell>cd /opt/continuent/software/shell>tungsten-clustering-7.1.4-10tools/tpm update --replace-release
On all the nodes in the new cluster, start the software:
shell> startallUsing cctrl, check that the new cluster appears and that all services are correctly showing online, it may take a few moments for the cluster to settle down and start everything
shell>cctrlcctrl>use {composite-dataservice}cctrl>lscctrl>exit
Check the output of trepctl and ensure all replicators are online and new cross-site services appear in the pre-existing clusters
shell>trepctl -service {service} statusshell>trepctl services
Place entire cluster back into AUTOMATIC
shell>cctrlcctrl>use {composite-dataservice}cctrl>set policy automaticcctrl>lsCOORDINATOR[db2:AUTOMATIC:ONLINE] london:COORDINATOR[db5:AUTOMATIC:ONLINE] nyc:COORDINATOR[db2:AUTOMATIC:ONLINE] cctrl>exit