RE: NameNode failover procedure
It seems there is no answer yet for all these questions and the wiki has not been updated. I do not understand the statement of just changing the DNS settings. How will that work exactly? We would have to change the masters list so that the secondary namenode is first on the list and it would work automatically? The files in the secondary namenode directory are quite different, how do they get used by a primary name node? It is still quite confusing to me. Thanks, Ankur -Original Message- From: Ted Dunning [mailto:[EMAIL PROTECTED] Sent: Friday, 20 July, 2007 1:07 PM To: hadoop-user@lucene.apache.org Subject: Re: NameNode failover procedure This is now on the wiki under NameNodeFailover and linked from the main page. There are some questions unanswered on that page, however. Could somebody who actually knows the answers (unlike me) edit that page to fill it out a bit? On 7/20/07 9:53 AM, Doug Cutting [EMAIL PROTECTED] wrote: 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. If you use DNS to switch the namenode from the primary to the secondary, then no configuration changes or other daemon restarts are required. I think that is the best practice.
Re: NameNode failover procedure
Andrzej Bialecki wrote: 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. If you use DNS to switch the namenode from the primary to the secondary, then no configuration changes or other daemon restarts are required. I think that is the best practice. Doug
Re: NameNode failover procedure
This is now on the wiki under NameNodeFailover and linked from the main page. There are some questions unanswered on that page, however. Could somebody who actually knows the answers (unlike me) edit that page to fill it out a bit? On 7/20/07 9:53 AM, Doug Cutting [EMAIL PROTECTED] wrote: 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. If you use DNS to switch the namenode from the primary to the secondary, then no configuration changes or other daemon restarts are required. I think that is the best practice.
