Hi all,
I've been reading the docs and the code, but I'm still somewhat hazy as
to what is the exact step-by-step procedure to perform a failover
between a primary NameNode and a SecondaryNameNode, in case the former
explodes or catches fire.
So far I learned that the secondary namenode keeps refreshing
periodically its backup copies of fsimage and editlog files, and if the
primary namenode disappears, it's the responsibility of the cluster
admin to notice this, shut down the cluster, switch the configs across
the cluster to point to the secondary namenode, start a primary namenode
on the secondary namenode's host, and restart the rest of the daemons.
In the meantime the other admin person frantically tries to restore the
primary namenode machine, and when it's ready we apply the process in
reverse, or we make it into a secondary namenode.
Any comments, clarifications and/or automation of this procedure are
welcome. ;)
--
Best regards,
Andrzej Bialecki <><
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