In early 2013, Yahoo! introduced multi-tenancy to HBase to offer it as a platform service for all Hadoop users. A certain degree of customization per tenant (a user or a project) was achieved through RegionServer groups, namespaces, and customized configs for each tenant. This talk covers how to accommodate diverse needs to individual tenants on the cluster, as well as operational tips and techniques that allow Yahoo! to automate the management of multi-tenant clusters at petabyte scale without errors.