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commit 3b60ddf1a3f039647db589aa641995cc81dd6857 Author: Andrew Wong <[email protected]> AuthorDate: Fri May 15 16:09:59 2020 -0700 docs: mention how to decommission a tablet server using the rebalancer Change-Id: I6f90eb352c4dce6d200cec33dde91c4bdb4aa522 Reviewed-on: http://gerrit.cloudera.org:8080/15929 Tested-by: Kudu Jenkins Reviewed-by: Alexey Serbin <[email protected]> Reviewed-by: Grant Henke <[email protected]> --- docs/administration.adoc | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-) diff --git a/docs/administration.adoc b/docs/administration.adoc index b4ca19f..48f7d71 100644 --- a/docs/administration.adoc +++ b/docs/administration.adoc @@ -1663,8 +1663,32 @@ movement. [[tablet_server_decommissioning]] === Decommissioning or Permanently Removing a Tablet Server From a Cluster -Kudu does not currently have an automated way to remove a tablet server from -a cluster permanently. Instead, use the following steps: +Starting with Kudu 1.12, the Kudu rebalancer tool can be used to decommission a +tablet server by supplying the `--ignored_tservers` and +`--move_replicas_from_ignored_tservers` arguments. + +WARNING: Do not decommission multiple tablet servers at once. To remove +multiple tablet servers from the cluster, follow the below instructions for +each tablet server, ensuring that the previous tablet server is removed from +the cluster and `ksck` is healthy before shutting down the next. + +. Ensure the cluster is in good health by using `ksck`. See <<ksck>>. +. Put the tablet server into + <<minimizing_cluster_disruption_during_temporary_single_ts_downtime,maintenance + mode>> by using the `kudu tserver state enter_maintenance` tool. +. Run `kudu cluster rebalance` tool, supplying the `--ignored_tservers` + argument with the UUIDs of the tablet servers to be decommissioned, and the + `--move_replicas_from_ignored_tservers` flag. +. Wait for the moves to complete and for `ksck` to show the cluster in a + healthy state. +. The decommissioned tablet server can be brought offline. +. To completely remove it from the cluster so `ksck` shows the cluster as + completely healthy, restart the masters. In the case of a single master, + this will cause cluster downtime. With multi-master, restart the masters in + sequence to avoid cluster downtime. + +In Kudu versions that do not support the above tooling, different steps must be +followed to decommission a tablet server: . Ensure the cluster is in good health using `ksck`. See <<ksck>>. . If the tablet server contains any replicas of tables with replication factor @@ -1682,11 +1706,6 @@ a cluster permanently. Instead, use the following steps: master, this will cause cluster downtime. With multi-master, restart the masters in sequence to avoid cluster downtime. -WARNING: Do not shut down multiple tablet servers at once. To remove multiple -tablet servers from the cluster, follow the above instructions for each tablet -server, ensuring that the previous tablet server is removed from the cluster and -`ksck` is healthy before shutting down the next. - [[using_cluster_names_in_kudu_tool]] === Using cluster names in the `kudu` command line tool
