Apache Kudu administration You can perform the following common administrative tasks and workflows with Apache Kudu: Starting and stopping Kudu processesYou can start, stop, and configure Kudu services to start automatilcally by using the CLI commands.Kudu web interfacesKudu tablet servers and masters expose useful operational information on a built-in web interface. Kudu metricsKudu daemons expose a large number of metrics. Some metrics are associated with an entire server process, whereas others are associated with a particular tablet replica.Rack awareness (Location awareness)Kudu supports a rack awareness feature. Kudu’s ordinary re-replication methods ensure the availability of the cluster in the event of a single node failure. However, clusters can be vulnerable to correlated failures of multiple nodes. For example, all of the physical hosts on the same rack in a datacenter may become unavailable simultaneously if the top-of-rack switch fails. Kudu’s rack awareness feature provides protection from certain kinds of correlated failures, such as the failure of a single rack in a datacenter.Common Kudu workflowsSome common Kudu administrative tasks include migrating to multiple Kudu masters, recovering from a dead Kudu master, removing unwanted masters from a multi-master deployment, adding or updating hostnames of the masters within the clusters without aliases, monitoring the health of the cluster using ksck, changing directory configuration, recovering from disk failures, bringing a tablet that has lost a majority of replicas back online, rebuilding a Kudu filesystem layout, taking physical backups of an entire node, and scale the storage for the Kudu master and the tablet severs in the cloud.Migrating Kudu data from one directory to another on the same hostTake the following steps to move the entire Kudu data from one directory to another.Minimizing cluster disruption during temporary planned downtime of a single tablet serverIf a single tablet server is brought down temporarily in a healthy cluster, all tablets will remain available and clients will function as normal, after potential short delays due to leader elections. However, if the downtime lasts for more than --follower_unavailable_considered_failed_sec (default 300) seconds, the tablet replicas on the down tablet server will be replaced by new replicas on available tablet servers. This will cause stress on the cluster as tablets re-replicate and, if the downtime lasts long enough, significant reduction in the number of replicas on the down tablet server, which may require the rebalancer to fix. Running tablet rebalancing toolThe kudu CLI contains a rebalancing tool that can be used to rebalance tablet replicas among tablet servers. For each table, the tool attempts to balance the number of replicas per tablet server. It will also, without unbalancing any table, attempt to even out the number of replicas per tablet server across the cluster as a whole.Decommissioning or permanently removing a tablet server from a clusterKudu does not currently support an automated way to remove a tablet server from a cluster permanently. Use the following steps to manually remove a tablet server:Using cluster names in the kudu command line toolWhen using the kudu command line tool, it can be difficult to remember the precise list of Kudu master RPC addresses needed to communicate with a cluster, especially when managing multiple clusters. As an alternative, you can use the command line tool to identify clusters by name.Managing Kudu with Cloudera ManagerThis topic describes the tasks you can perform to manage the Kudu service using Cloudera Manager. You can use Cloudera Manager to start and stop the Kudu service, monitor operations, and configure the Kudu master and tablet servers, among other tasks. Depending on your deployment, there are several different configuration settings you may need to modify.Kudu securityKudu includes security features that allow Kudu clusters to be hardened against access from unauthorized users. Kudu uses strong authentication with Kerberos, while communication between Kudu clients and servers can now be encrypted with TLS. Kudu also allows you to use HTTPS encryption to connect to the web UI.Apache Kudu background maintenance tasksKudu relies on running background tasks for many important maintenance activities. These tasks include flushing data from memory to disk, compacting data to improve performance, freeing up disk space, and more.
