How to find active namenode from cli

khanarshadazmat — Sun, 30 May 2021 11:31:43 GMT

Hi Team,

How to find active name node from cli and also want to know where to check automatic namenode failover triggered in the cluster?

Re: How to find active namenode from cli

vamsi_redd — Sun, 30 May 2021 13:19:22 GMT

Hi,

You can use the below ambari api to get the Active NN:

http://{HOST}:8080/api/v1/clusters/{CLUSTER_NAME}/host_components?HostRoles/component_name=NAMENODE&...

Re: How to find active namenode from cli

khanarshadazmat — Mon, 31 May 2021 06:39:25 GMT

Thanks to @vamsi_redd for helping us with Ambari API.

Do you have the same API for Cloudera Manager as well?

Re: How to find active namenode from cli

tjangid — Mon, 31 May 2021 07:42:44 GMT

Hello @khanarshadazmat ,

You may get the role information using CM API for HDFS service.

API:

https://archive.cloudera.com/cm7/7.2.4/generic/jar/cm_api/apidocs/resource_RolesResource.html#resource_RolesResource_ClustersResourceV43_ServicesResourceV42_RolesResourceV41_readRoles_GET

See the below example for a better understanding:

• When I execute the above API, I would get the below details for HDFS service:

 "name" : "HDFS-1-NAMENODE-cb7144bc695976e34cfbaaf26c176d21",
    "type" : "NAMENODE",
    "serviceRef" : {
      "clusterName" : "Cluster 1",
      "serviceName" : "HDFS-1",
      "serviceDisplayName" : "HDFS-1",
      "serviceType" : "HDFS"
    },
...
    "roleState" : "STARTED",
    "healthSummary" : "GOOD",
    "configStalenessStatus" : "FRESH",
    "haStatus" : "STANDBY",
    "maintenanceMode" : false,
    "commissionState" : "COMMISSIONED",
    "roleConfigGroupRef" : {
      "roleConfigGroupName" : "HDFS-1-NAMENODE-BASE"
    },

• and, for the second namenode, I'll get something as below:

"name" : "HDFS-1-NAMENODE-b1d777dd6714507397225b07ea9057ce",
    "type" : "NAMENODE",
    "serviceRef" : {
      "clusterName" : "Cluster 1",
      "serviceName" : "HDFS-1",
      "serviceDisplayName" : "HDFS-1",
      "serviceType" : "HDFS"
    },
...
   "roleState" : "STARTED",
    "healthSummary" : "GOOD",
    "configStalenessStatus" : "FRESH",
    "haStatus" : "ACTIVE",
    "maintenanceMode" : false,
    "commissionState" : "COMMISSIONED",
    "roleConfigGroupRef" : {
      "roleConfigGroupName" : "HDFS-1-NAMENODE-BASE"
    },
    "entityStatus" : "GOOD_HEALTH"

• In both the above examples, check for the keyword "haStatus". The namenode with haStatus as Active would be your Active Namenode.

Let me know if this helps.

Cheers!

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