How do Zookeeper save HBase Column and Column Family metadata in Znode?

[#1]

I am trying to write a zookeeper watcher to monitor hbase column family and hbase column modification.

I know Hbase table is saved as a znode under the /table znode, but I did not get much info about how do zookeeper save the metadata of hbase column family and hbase column, so How can I get notified when there is any modification in hbase column family or hbase columns ?

[#2]

Table metadata is stored as table descriptor in the corresponding table directory and is read and altered there itself. I don't think that we have any znode where we keep the information of columnfamily during alter or create table.

[#3]

Where is that table directory? Is it also in Zookeeper？

[#4]

it is in hdfs and if you are using HDP then it may be under /apps/hbase/data/data/<namespace>/<tableName>/.tabledesc/

[#5 · Accepted solution]

The best way to observe and run custom logic when a table is modified would be to write a master coprocessor. Your MasterObserver will be called before and after any table is modified (see https://hbase.apache.org/book.html#cp).

However, unlike column families, columns in HBase are not predefined. So you cannot observe column changes since there is no fixed "schema". Please read up on the HBase data model.

[#6]

Thanks I think that solves my problem, I used to use the Zookeeper watcher but it can only get the hbase table modification.