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From "Jayush Luniya (JIRA)" <>
Subject [jira] [Commented] (AMBARI-16028) Namenode marked as INITIAL standby could potentially never start if other namenode is down
Date Thu, 21 Apr 2016 22:14:12 GMT


Jayush Luniya commented on AMBARI-16028:

# The fix is to maintain a bootstrap marker file (similar to the way we keep a name node formatted
marker file)
# In the INITIAL_START phase (during cluster deployment) we will always force bootstrap so
as to enforce the name node marked as Standby to wait for the Active name node to come up,
bootstrap and start in STANDBY node.
# Once we are out of INITIAL_START phase, we will bootstrap only if this name node has not
been bootstrapped in the past. 
# We will not enforce bootstrapping only in the INITIAL_START phase because there is a possibility
during cluster deployment that both name nodes don’t start and hence bootstrapping out of
INITIAL_START phase would be required in this case.

> Namenode marked as INITIAL standby could potentially never start if other namenode is
> ------------------------------------------------------------------------------------------
>                 Key: AMBARI-16028
>                 URL:
>             Project: Ambari
>          Issue Type: Bug
>          Components: stacks
>    Affects Versions: 2.2.0
>            Reporter: Jayush Luniya
>            Priority: Critical
>             Fix For: 2.4.0
> *Issue:*
> # During Namenode HA blueprint deployment, we configure the name nodes to start in active/standby
mode based on the following properties
> {code}
>      {
>         "hadoop-env": {
>           "properties" : {
>             "dfs_ha_initial_namenode_active" : "jay-msft-1.c.pramod-thangali.internal",
>             "dfs_ha_initial_namenode_standby" : "jay-msft-2.c.pramod-thangali.internal”
>           }
>         }
>       }
> {code}
> # The current logic is to always bootstrap the name node marked as standby. 
> # This will lead to the Namenode marked as Standby to never start under the following
> - Cluster is deployed successfully
> - Both name nodes are stopped
> - Start the name node marked as standby. Namenode will never start.
> - This is because the standby name node will try to bootstrap again. 
> - However to bootstrap a name node an active name node is required. Based on the HDFS
logic the first step done when bootstrapping is to connect to the Active Namenode. 
> - Also there is no need to bootstrap here as the name node should already be bootstrapped
and should come back up as “Active"

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