7. Configure NameNode HA for RHEL Cluster

Follow the tasks listed below to configure NameNode HA:

7.1. Install NameNode monitoring component

Step 1: Stop all the HDP services that are currently running on your cluster.

Use the instructions provided here.

Step 2: Stop the RHEL cluster NameNodeService service.

Use the RHEL Cluster administration tools (RHEL v5.x., RHEL v6.x.).

Step 3: Install the NameNode monitoring component on all the nodes in your RHEL HA cluster.

Ensure that you have set up the HDP repository on the RHEL HA cluster nodes as part of the HDP installation. Use the instructions provided here.

Install the RPMs.

For RHEL/CentOS 5

        wget http://public-repo-1.hortonworks.com/HDP/centos5/1.x/updates/1.2.1/hamonitor_redhat/hmonitor-resource-agent-1.1.0.23-1.el5.x86_64.rpm
        wget http://public-repo-1.hortonworks.com/HDP/centos5/1.x/updates/1.2.1/hamonitor_redhat/hmonitor-1.1.0.23-1.el5.x86_64.rpm
yum install hmonitor-1.1.0.23-1.el5.x86_64.rpm
yum install hmonitor-resource-agent-1.1.0.23*.rpm

For RHEL/CentOS 6

        wget http://public-repo-1.hortonworks.com/HDP/centos5/1.x/updates/1.2.1/hamonitor_redhat/hmonitor-resource-agent-1.1.0.23-1.el6.x86_64.rpm
        wget http://public-repo-1.hortonworks.com/HDP/centos5/1.x/updates/1.2.1/hamonitor_redhat/hmonitor-1.1.0.23-1.el6.x86_64.rpm
yum install hmonitor-1.1.0.23-1.el6.x86_64.rpm
yum install hmonitor-resource-agent-1.1.0.23*.rpm

7.2. Configure NameNode service in clustering configuration

Edit the /etc/cluster/cluster.conf file to add the service domain specifications. You can use the following sample configuration. (Note that this sample configuration is for a small cluster and the timeouts for booting, probing, and stopping have been reduced to a minimum.)

<service domain="HANameNode" name="NameNodeService" recovery="restart">
  <ip address="10.10.10.89" sleeptime="10"/>
  <netfs export="/hdp/hadoop-nfs" force_unmount="1" fstype="nfs"
         host="10.10.10.88" mountpoint="/hdp/hadoop/hdfs/nn"
         name="HDFS data" options="rw,soft,nolock"/>
  <hadoop
         __independent_subtree="1" __max_restarts="10"
         __restart_expire_time="600" name="NameNode Process"
         daemon="namenode" boottime="10000" probetime="10000"
         stoptime="10000"
         url="http://10.0.0.30:50070/dfshealth.jsp"
         pid="/var/run/hadoop/hdfs/hadoop-hdfs-namenode.pid"
         path="/"/>
</service>

The following table explains the parameters used in the above configuration:

Table 3.1. Parameters for configuring NameNode service in clustering configuration
Name	Description	Mandatory/Optional
daemon	Name of the hadoop service which will be started by `bin/hadoop-daemon`.	Mandatory
url	URL to check for the service web page. This should be on the floating IP address.	Mandatory
pid	Process ID of the NameNode process. (Default: “”)	Optional
path	Path under DFS to probe. (Default: /)	Optional
boottime	Time (in milliseconds) to allow for the service to boot up. This must include any activities that take place before the service web pages and IPC services are reachable. For the NameNode, it must include the time for the edit log to be replayed. (Default: 180000)	Optional
probetime	Time (in milliseconds) to allow for a process to respond to liveness probes. This duration must be longer than the maximum expected GC pause. (Default: 120000)	Optional
stoptime	Time (in milliseconds) to allow for a clean shutdown before forcibly killing a process. (Default: 60000)	Optional

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