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Converting a MySQL standalone cluster to a Composite Primary/DR topology using INI configuration

In this blog post, we demonstrate how to convert a single standalone MySQL cluster into a Composite Primary/DR topology running in two data centers.

Our example starting cluster has 5 nodes (1 master and 4 slaves) and uses service name alpha. Our target cluster will have 6 nodes (3 per cluster) in 2 member clusters alpha_east and alpha_west in composite service alpha.

This means that we will reuse the existing service name alpha as the name of the new composite service, and create two new service names, one for each cluster (alpha_east and alpha_west).

Below is an INI file extract example for our starting standalone cluster with 5 nodes:

[defaults]
...
 
[alpha]
connectors=db1,db2,db3,db4,db5
master=db1
members=db1,db2,db3,db4,db5
topology=clustered

To convert the above configuration to a Composite Primary/DR:

  1. First you must stop all services on all existing nodes:
    shell> stopall
  2. Update tungsten.ini on all nodes.
    Create the two new services and put the correct information into all three stanzas.
    For example, below is an INI file extract example for our target composite cluster with 6 nodes:
    [defaults]
    start-and-report=false
    start=false
    ...
     
    [alpha_east]
    connectors=db1,db2,db3
    master=db1
    members=db1,db2,db3
    topology=clustered
     
    [alpha_west]
    connectors=db4,db6
    master=db4
    members=db4,db5,db6
    topology=clustered
    relay-source=alpha_east
     
    [alpha]
    composite-datasources=alpha_east,alpha_west
  3. Invoke the conversion using the tpm command from the software extraction directory:
    shell> tpm query staging
    shell> cd {software_staging_dir_from_tpm_query}
    shell> ./tools/tpm update --replace-release
    shell> rm /opt/cont/tung/cluster-home/conf/cluster/*/datasource/*
  4. Finally, start all services on all existing nodes.
    shell> startall

In future articles, we will continue to cover more advanced subjects of interest!

Questions? Contact Continuent

About the Author

Eric M. Stone
COO

Eric is a veteran of fast-paced, large-scale enterprise environments with 35 years of Information Technology experience. With a focus on HA/DR, from building data centers and trading floors to world-wide deployments, Eric has architected, coded, deployed and administered systems for a wide variety of disparate customers, from Fortune 500 financial institutions to SMB’s.

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