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Checking the status of your nodes


You can use the node status command to check the status of a target node in your HCP system. Any user can perform the node status command. System-level users with the administrator role can enable and disable the node status API. For more information on enabling this service, see Setting network security.

The request to check the status of a node requires a URL specifying the front-end IP address of the target node. You enter the command in the following format:

http://node-front-end-ip-address/node_status

You can also request node metrics to be returned with the node HTTP status return code. To request node metrics, you additionally need to:

Specify a type URL query parameter with a value of metrics.

Specify the format URL query parameter with a value of xml or json.

If you omit the format parameter, you are only returned a response status code.

© 2015, 2019 Hitachi Vantara Corporation. All rights reserved.

Request-specific return codes (node status)


The table below describes the HTTP return status codes that can be returned from a node status request.

Code HTTP status Description
204 OK Node is configured to return node status
403 Forbidden

The HCP node status check returns a 403 forbidden message for the following reasons: 

The system administrator has not enabled node status through the System Management Console. For more information on enabling node status, see Setting network security.

The HCP system does not have a load balancer or the system administrator has not added the load balancer IP address to the Security Console Allow list. For more information on adding the load balancer IP address to the all list, see Controlling access to the System Management Console.

540   System is in Read Only mode
541   Node is not available

© 2015, 2019 Hitachi Vantara Corporation. All rights reserved.

Response body (node status)


The table below describes the properties included in the node status metrics.

Property name Data type Description
httpConnections integer

The number of HTTP connections.

cpuUser float The percentage of CPU capacity used by HCP processes.
cpuSystem float The percentage of CPU capacity used by the operating system kernel.
iowait float The percentage of CPU capacity spent waiting to access logical volumes that are in use by other processes.
swapout float The average number of pages swapped out of memory per second.
id float The volume name.
blocksRead float The average number of blocks read from the logical volume per second.
blocksWrite float The average number of blocks written to the logical volume per second.
diskUtilization float The usage of the communication channel between the operating system and the logical volume as a percent of the channel bandwidth.
frontendBytesRead float The average number of bytes read from the node per second over the front-end network.
frontendBytesWrite float The average number of bytes written to the node per second over the front-end network.
backendBytesRead float The average number of bytes read from the node per second over the back-end network.
backendBytesWrite float The average number of bytes written to the node per second over the back-end network.
requestTimestamp integer The exact time that the timestamp request was issued in milliseconds.
metricsTimestamp integer The exact time that the metrics were collected in milliseconds.

© 2015, 2019 Hitachi Vantara Corporation. All rights reserved.

Example: Retrieving node status


Here's a sample request that retrieves a return status code and node metrics for a node in the system. In this example, the target node IP address is 192.168.210.16 and the requested output format is JSON.

Request with cURL command line

curl -i http://192.168.210.16/node_status?ty...cs&format=json

Response headers

HTTP/1.1 200 OK

Response body in JSON

{
    "httpConnections" : "10000",
    "cpuUser" : "0.36",
    "cpuSystem" : "0.56",
    "iowait" : "0.05",
    "swapout" : "0.00",
    "volume" : [ {
        "id" : "archive034",
        "blocksRead" : "0.00",
        "blocksWrite" : "0.29",
        "diskUtilization" : "0.00"
    }, {
        "id" : "archive033",
        "blocksRead" : "0.00",
        "blocksWrite" : "0.59",
        "diskUtilization" : "0.00"
    } ],
    "frontendBytesRead" : "0.14",
    "frontendBytesWrite" : "0.00",
    "backendBytesRead" : "0.83",
    "backendBytesWrite" : "0.59",
    "requestTimestamp" : "1509726379318",
    "metricsTimestamp" : "1509726014000"
}

© 2015, 2019 Hitachi Vantara Corporation. All rights reserved.