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https://issues.apache.org/jira/browse/HBASE-24833?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17411588#comment-17411588
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Zach York commented on HBASE-24833:
-----------------------------------
Give me a day to review please. I was working with this on this problem for 2.4
as well and want to make sure we include everything I found related to this.
> Bootstrap should not delete the META table directory if it's not partial
> ------------------------------------------------------------------------
>
> Key: HBASE-24833
> URL: https://issues.apache.org/jira/browse/HBASE-24833
> Project: HBase
> Issue Type: Sub-task
> Affects Versions: 3.0.0-alpha-1, 2.3.0, 2.3.1, 2.3.3
> Reporter: Tak-Lon (Stephen) Wu
> Assignee: Tak-Lon (Stephen) Wu
> Priority: Major
>
> this issues were discussed in
> [PR#2113|https://github.com/apache/hbase/pull/2113] as part of HBASE-24286,
> and it is a dependencies before we solve HBASE-24286.
> The changes were introduced in [HBASE-24471
> |https://github.com/apache/hbase/commit/4d5efec76718032a1e55024fd5133409e4be3cb8#diff-21659161b1393e6632730dcbea205fd8R70-R89]
> that partial meta was introduced and `partial` was defined as
> InitMetaProcedure did not succeed and INIT_META_ASSIGN_META was not completed.
> {code:java}
> private static void writeFsLayout(Path rootDir, Configuration conf) throws
> IOException {
> LOG.info("BOOTSTRAP: creating hbase:meta region");
> FileSystem fs = rootDir.getFileSystem(conf);
> Path tableDir = CommonFSUtils.getTableDir(rootDir,
> TableName.META_TABLE_NAME);
> if (fs.exists(tableDir) && !fs.delete(tableDir, true)) {
> LOG.warn("Can not delete partial created meta table, continue...");
> }
> {code}
> however, in the cloud use case where HFiles store on S3, WALs store on HDFS,
> ZK data are stored within the cluster, this partial meta becomes a block when
> cluster recreate on existing HFiles; Here, Zk data and WALs cannot be
> retained (HDFS was associated with cloud instance and was terminated
> together) when cluster recreates on the flushed HFiles, and existing meta are
> always considered as partial and deleted in `INIT_META_WRITE_FS_LAYOUT`
> during bootstrap. As a result, the recreate cluster starts with a empty meta
> table, either the cluster hangs during the master initialization (branch-2)
> because table states of namespace table cannot be assigned, or starts as a
> fresh cluster without any region assigned and table opens (may need HBCK to
> rebuild the meta).
> Potential solution suggested by Anoop
> {quote}In case of HM start and the bootstrap we create the ClusterID and
> write to FS and then to zk and then create the META table FS layout. So in a
> cluster recreate, we will see clusterID is there in FS and also the META FS
> layout but no clusterID in zk. Ya seems we can use this as indication for
> cluster recreate over existing data. In HM start, this is some thing we need
> to check at 1st itself and track. If this mode is true, later when (if) we do
> INIT_META_WRITE_FS_LAYOUT , we should not delete the META dir. As part of the
> Bootstrap when we write that proc to MasterProcWal, we can include this mode
> (boolean) info also. This is a protobuf message anyways. So even if this HM
> got killed and restarted (at a point where the clusterId was written to zk
> but the Meta FS layout part was not reached) we can use the info added as
> part of the bootstrap wal entry and make sure NOT to delete the meta dir.
> {quote}
> In this JIRA, we're going to fix the `partial` definition when we found
> cluster ID was stored in HFiles but ZK were deleted or fresh on cluster
> creates.
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