Information and discussion related to the Kognitio on Hadoop product
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Configure Kognitio to work with Namenode High Availability

by tajones » Thu Jul 26, 2018 7:14 pm

We currently have High Availability enabled for our Namenode in our non-prod environment. We would like to implement this in production but need to know what, if anything will need to be changed/configured in Kognitio. I've searched the documentation and I've looked through configs and settings on the edge node and in the console but don't see anything specifically referencing our namenode. Are there changes we will need to make? Any direction would be appreciated. Thank you!
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Re: Configure Kognitio to work with Namenode High Availability

by skkirkham » Thu Aug 02, 2018 10:18 am

Hi tajones

When you turn on HA for an Hadoop system that already has Kognitio installed you will need to conduct a Slider rebuild for Kognitio to get the cluster working again. This is because Slider hard codes things like the namenode's uri into its cluster definitions and this changes when you turn on HA. A Slider rebuild requires the cluster to be stopped first. The following commands should be run:

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kodoop cluster <cluster name> stop
# Turn on HA at this point
kodoop cluster <cluster name> rebuild_slider
kodoop cluster <cluster name> start 
For Kognitio 8.2.1 onwards the cluster start command will also automatically restart the server too. Otherwise you will have to restart your server using:

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kodoop server <cluster name> start
Once the server is up if you have any connectors created you should also check they do not have the namenode uri hardcoded into their target definition. These will need editing if they do:

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ALTER CONNECTOR <your connector> SET TARGET TO 'namenode <new ha name:port>, user <hdfsuser>'
Once these are altered you should test each before recreating any RAM images based on external tables.
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