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12-12-2024
09:40 AM
Though one can do the manual intervention to fix the under replicated blocks, HDFS has matured a lot and the NameNode will take care of fixing the under replicated blocks on its own. The drawback for doing the manual step is that it may add additional load to the NameNode Operations and may cause performance degradation with existing jobs. So if you plan to do manually you may do it at least business hours or over the weekend.
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08-02-2018
07:29 PM
Bless you!!
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04-16-2019
01:08 PM
Referring to the PUT command used for triggering the alert manually, Is it possible to pass some parameters/custom information to the script which gets trigged by the alert ? If yes, is it via headers OR body of the PUT request ? Thanks.
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08-27-2018
08:30 PM
The article doesn't indicate this, so for reference, the listed HDFS settings do not exist by default. These settings, as shown below, need to go into hdfs-site.xml, which is done in Ambari by adding fields under "Custom hdfs-site". dfs.namenode.rpc-bind-host=0.0.0.0 dfs.namenode.servicerpc-bind-host=0.0.0.0 dfs.namenode.http-bind-host=0.0.0.0 dfs.namenode.https-bind-host=0.0.0.0 Additionally, I found that after making this change, both NameNodes under HA came up as stand-by; the article at https://community.hortonworks.com/articles/2307/adding-a-service-rpc-port-to-an-existing-ha-cluste.html got me the missing step of running a ZK format. I have not tested the steps below against a Production cluster and if you foolishly choose to follow these steps, you do so at a very large degree of risk (you could lose all of the data in your cluster). That said, this worked for me in a non-Prod environment: 01) Note the Active NameNode. 02) In Ambari, stop ALL services except for ZooKeeper. 03) In Ambari, make the indicated changes to HDFS. 04) Get to the command line on the Active NameNode (see Step 1 above). 05) At the command line you opened in Step 4, run: `sudo -u hdfs hdfs zkfc -formatZK` 06) Start the JournalNodes. 07) Start the zKFCs. 08) Start the NameNodes, which should come up as Active and Standby. If they don't, you're on your own (see the "high risk" caveat above). 09) Start the DataNodes. 10) Restart / Refresh any remaining HDFS components which have stale configs. 11) Start the remaining cluster services. It would be great if HWX could vet my procedure and update the article accordingly (hint, hint).
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