Retrieving Metric Data¶

Filtering the Metric Data Output¶

You can also use the following query parameters with these methods to filter the output:

Results of calls to retrieve metrics are returned in the following format:

{
  [<node_ip>: | <device>: | <keyspace.columnfamily>:]
    {
      <function>:
        [
          [<timestamp> <value>],
          ...
        ]
    }
}

By default, the output is metric data points at 60-second intervals over a 24-hour period. Data points are listed in chronological order, starting with the oldest data point first.

GET /{cluster_id}/cluster-metrics/{dc}/{metric}¶

Aggregate a metric across multiple nodes in the cluster rather than retrieving data about a single node.

Path arguments:	cluster_id -- A Cluster Config ID. dc -- The name of the data center for the nodes. Use the name all to aggregate a metric across all data centers. metric -- One of the Cluster Metrics Keys.
Query params:	parameters -- The parameters listed in Filtering the Metric Data Output.

Returns metric data across multiple nodes in a cluster.

Example

Get the average write requests per second over to the cluster over all data centers on May 1, 2012 from 8 AM to 5 PM GMT. Show data points at 2-hour (120-minute) intervals.

curl -G
  http://127.0.0.1:8888/Test_Cluster/cluster-metrics/all/write-ops
    -d 'step=120'
    -d 'start=1335859200'
    -d 'end=1335891600'
    -d 'function=average'

Output:

Data points at 2-hour (7200 seconds) intervals show the number of write requests per second during business hours on May 1.

{
  "Total": {
    "AVERAGE": [
      [
        1335859200,
        null
      ],
      [
        1335866400,
        13.376885890960693
      ],
      [
        1335873600,
        13.372154712677002
      ],
      [
        1335880800,
        13.365732669830322
      ],
      [
        1335888000,
        13.392115592956543
      ]
    ]
  }
}

GET /{cluster_id}/cluster-metrics/{dc}/{metric}/{device}¶

Aggregate a disk or network metric, which pertains to a specific device, across multiple nodes in the cluster rather than retrieving data about a single node.

Path arguments:

cluster_id -- A Cluster Config ID. dc -- The name of the data center for the nodes. Use the name all to aggregate a metric across all data centers. metric -- One of the Cluster Metrics Keys or Operating System Metrics Keys. device -- The device to be measured, which the Node object lists. Use the name all to measure all devices, For example, when requesting a disk metric, all will aggregate metrics from all disk devices.

Query params:

parameters -- The parameters listed in Filtering the Metric Data Output.

Examples of Device Arguments

To determine the set of network interfaces that metrics are available for, you can run a query similar to the following:

curl http://localhost:8888/Test_Cluster/nodes/192.168.1.1/network_interfaces

["lo0", "eth0", "eth1"]

In this case, lo0, eth0, and eth1 can all be used.

Disk devices can be discovered in a similar way.

curl http://localhost:8888/Test_Cluster/nodes/192.168.1.1/devices

{
  "commitlog": "sdb",
  "data": ["sda"],
  "saved_caches": "sda",
  "other": ["sdc"]
}

In this case, any of sda, sdb, or sdc may be used.

Finally, metrics are also captured for disk partitions and filesystems:

curl http://localhost:8888/Test_Cluster/nodes/192.168.1.1/partitions

{
  "commitlog": "/dev/sdb1",
  "data": ["/dev/sda1"],
  "saved_caches": "/dev/sda1",
  "other": ["/dev/sdc1"]
}

Here, the available partitions are /dev/sda1, /dev/sdb1, and /dev/sdc1. Keep in mind that you will need to URL-encode the items, so /dev/sda1 will become %2Fdev%2Fsda1.

Using a partition, network interface, or other device name for the device argument returns disk or network metric data about a specific device across multiple nodes. Using all for the device name returns a dictionary of keys (device names) and the values (results for that device).

Example

Get the average GB of space on all disks in all data centers used each day by the cluster from April 11, 2012 00:00:00 to April 26, 2012 00:00:00 GMT.

curl -G
  http://127.0.0.1:8888/Test_Cluster/cluster-metrics/all/os-disk-used/all
    -d 'step=1440'
    -d 'start=1334102400'
    -d 'end=1335398400'
    -d 'function=average'

Output:

{
  "Total": {
    "AVERAGE": [
      [
        1334102400,
        null
      ],
      [
        1334188800,
        21.000694274902344
      ],
      [
        1334275200,
        8.736943244934082
      ],
      [
        1334361600,
        9.0
      ],
      [
        1334448000,
        19.0
      ],
      [
        1334534400,
        19.0
      ],
      [
        1334620800,
        19.0
      ],
      [
        1334707200,
        19.0
      ],
      [
        1334793600,
        18.629029273986816
      ],
      [
        1334880000,
        19.923184394836426
      ],
      [
        1334966400,
        25.0
      ],
      [
        1335052800,
        25.0
      ],
      [
        1335139200,
        25.923053741455078
      ],
      [
        1335225600,
        26.0
      ],
      [
        1335312000,
        26.549484252929688
      ]
    ]
  }
}

GET /{cluster_id}/cluster-metrics/{dc}/{ks_name}/{cf_name}/{metric}¶

Aggregate a column family metric across multiple nodes in the cluster rather than retrieving data about a single node.

Path arguments:	cluster_id -- A Cluster Config ID. dc -- The name of the data center for the nodes. Use the name all to aggregate a metric across all data centers. ks_name -- The keyspace that contains the column family to be measured. cf_name -- The column family to be measured. metric -- One of the Column Family Metrics Keys.
Query params:	parameters -- The parameters listed in Filtering the Metric Data Output.

Returns metric data for multiple nodes.

Example

Get the maximum bytes of disk space used for live data by the Users column family in the Keyspace1 keyspace of the cluster over all data centers from May 1, 2012 00:00:00 to May 5, 2012 00:00:00 GMT:

curl -G
  http://127.0.0.1:8888/Test_Cluster/cluster-metrics/all/Keyspace1/Users/cf-live-disk-used
  -d 'function=max'
  -d 'start=1335830400'
  -d 'end=1336176000'
  -d 'step=1440'

Output:

Data points at 24-hour intervals show the metrics for the period.

{

  "Total": {
    "MAX": [
      [
        1335830400,
        9740462592.0
      ],
      [
        1335916800,
        9932527616.0
      ],
      [
        1336003200,
        null
      ],
      [
        1336089600,
        10644448512.0
      ]
    ]
  }
}

GET /{cluster_id}/metrics/{node_ip}/{metric}¶

Retrieve metric data for a single node.

Path arguments:	cluster_id -- A Cluster Config ID. node_ip -- IP address of the target Node. metric -- One of the Cluster Metrics Keys.
Query params:	parameters -- The parameters listed in Filtering the Metric Data Output.

Returns metric data for a single node.

Example

Get the daily average data load on cluster node 10.11.12.150 from April 20, 2012 00:00:00 to April 26, 2012 00:00:00 GMT:

curl -G
http://127.0.0.1:8888/Test_Cluster/metrics/10.11.12.150/data-load
  -d 'step=1440'
  -d 'start=1334880000'
  -d 'end=1335398400'
  -d 'function=average'

Output:

{
  "10.11.12.150": {
    "AVERAGE": [
      [
        1334880000,
        null
      ],
      [
        1334966400,
        6353770496.0
      ],
      [
        1335052800,
        6560092672.0
      ],
      [
        1335139200,
        6019291136.0
      ],
      [
        1335225600,
        6149050880.0
      ],
      [
        1335312000,
        6271239680.0
      ]
    ]
  }
}

GET /{cluster_id}/metrics/{node_ip}/{metric}/{device}¶

Aggregate a disk or network metric for a single node.

Path arguments:	cluster_id -- A Cluster Config ID. node_ip -- IP address of the target Node. metric -- One of the Cluster Metrics Keys or Operating System Metrics Keys. device -- The device to be measured. Use the name all to measure all devices associated with a disk metric. See GET /{cluster_id}/cluster-metrics/{dc}/{metric}/{device} for examples of devices.
Query params:	parameters -- The parameters listed in Filtering the Metric Data Output.

Returns disk or network metrics data for a single node.

Example

Get the maximum GB of disk space for all disks used by cluster node 10.11.12.150 from April 30, 2012 at 22:05 to May 1, 2012 8:00:00 GMT:

curl -G
http://127.0.0.1:8888/Test_Cluster/metrics/10.11.12.150/os-disk-used/all
  -d 'start=1335823500'
  -d 'end=1335859200'
  -d 'step=120'
  -d 'function=max'

Output:

Data points at 2-minute intervals show the disk space used by device /dev/sda1.

{
  "/dev/sda1": {
    "MAX": [
      [
        1335823200,
        null
      ],
      [
        1335830400,
        17.0
      ],
      [
        1335837600,
        16.0
      ],
      [
        1335844800,
        17.0
      ],
      [
        1335852000,
        16.0
      ]
    ]
  }
}

GET /{cluster_id}/metrics/{node_ip}/{ks_name}/{cf_name}/{metric}¶

Retrieve metric data about a column family on a single node.

Path arguments:	cluster_id -- A Cluster Config ID. node_ip -- IP address of the target Node. ks_name -- The keyspace that contains the column family to be measured. cf_name -- The column family to be measured. metric -- One of the Column Family Metrics Keys.
Query params:	parameters -- The parameters listed in Filtering the Metric Data Output.

Example

Get the daily, maximum response time (in microseconds) to write requests on the Users column family in the Keyspace1 keyspace by cluster node 10.11.12.150 from May 1, 2012 at 00:00:00 to May 5, 2012 00:00:00 GMT.

curl -G
http://127.0.0.1:8888/Test_Cluster/metrics/10.11.12.150/Keyspace1/Users/cf-write-latency-op
  -d 'function=max'
  -d 'start=1335830400'
  -d 'end=1336176000'
  -d 'step=1440'

Output:

{
  "OpsCenter.rollups60": {
    "MAX": [
      [
        1335830400,
        102.28681945800781
      ],
      [
        1335916800,
        124.86614227294922
      ],
      [
        1336003200,
        null
      ],
      [
        1336089600,
        127.14733123779297
      ]
    ]
  }
}

Metrics Attribute Key Lists¶

This section contains these tables of metric keys to use with resources that retrieve OpsCenter performance data:

• Cluster Metrics Keys
• Column Family Metrics Keys
• Operating System Metrics Keys