question Re: can reisntallation wipe hdfs data ? in Archives of Support Questions (Read Only)

can reisntallation wipe hdfs data ?

tdamineni — Tue, 26 Sep 2017 04:47:42 GMT

We are still building this 7 node cluster, and before we finish building it, our name node and the ambari-server which are co-existing on the same node died due to manual error related to OS. If I perform a re-installation (of both Ambari-server and Namenode) on the same node with fresh OS installed, will it wipe my data ? What about the services ? do I have to completely remove all services and re-install them ? Please note that this cluster is still under work, while this happened, and we did not configure HA.

Re: can reisntallation wipe hdfs data ?

ajay_kumar — Tue, 26 Sep 2017 06:22:53 GMT

@Teja Damineni

If I perform a re-installation (of both Ambari-server and Namenode) on the same node with fresh OS installed, will it wipe my data ?

If you have taken backup of NameNode metadata you can use it to reset the NameNode. Without the backup you can't recover your data.

What about the services ?do I have to completely remove all services and re-install them ?

If you have backup of ambari database you can use it to reinitialize ambari to its old state, else you have to reinstall everything.

Re: can reisntallation wipe hdfs data ?

tdamineni — Tue, 26 Sep 2017 08:47:41 GMT

@Ajay I absolutely do not have any backup of this cluster of any sort. However, the secondary Name node seems to be up more days than Primary Name node. Our UNIX admins, did a OS refresh without touching /data, so the data was safe. Before starting anything on this cluster, I did put it on safe mode. I did a re-install and luckily I had the document from the first install and I have chosen . YARN and HBase are acting up crazy, but all the Hdfs data is right there.... adn the cluster is up and green. We will have to integrate AD and Kerberos. But so far so good.

Re: can reisntallation wipe hdfs data ?

ajay_kumar — Tue, 26 Sep 2017 09:36:43 GMT

@Teja Damineni

Good to know that your data is safe. Recommend taking regular backup of NameNode metadata to avoid any future issues.