vmpooler

vmpooler provides configurable 'pools' of available (running) virtual machines.

Usage

At Puppet Labs we run acceptance tests on thousands of disposable VMs every day. Dynamic cloning of VM templates initially worked fine for this, but added several seconds to each test run and was unable to account for failed clone tasks. By pushing these operations to a backend service, we were able to both speed up tests and eliminate test failures due to underlying infrastructure failures.

Installation

Prerequisites

vmpooler requires the following Ruby gems be installed:

• json
• rbvmomi
• redis
• sinatra

It also requires that a Redis server exists somewhere, as this is the datastore used for vmpooler's inventory and queueing services.

Configuration

The following YAML configuration sets up two pools, debian-7-i386 and debian-7-x86_64, which contain 5 running VMs each:

---
:vsphere:
  server: 'vsphere.company.com'
  username: 'vmpooler'
  password: 'swimsw1msw!m'

:redis:
  server: 'redis.company.com'

:config:
  logfile: '/var/log/vmpooler.log'

:pools:
  - name: 'debian-7-i386'
    template: 'Templates/debian-7-i386'
    folder: 'Pooled VMs/debian-7-i386'
    pool: 'Pooled VMs/debian-7-i386'
    datastore: 'vmstorage'
    size: 5
  - name: 'debian-7-x86_64'
    template: 'Templates/debian-7-x86_64'
    folder: 'Pooled VMs/debian-7-x86_64'
    pool: 'Pooled VMs/debian-7-x86_64'
    datastore: 'vmstorage'
    size: 5

See the provided YAML configuration example, vmpooler.yaml.example, for additional configuration options and parameters.

Template set-up

Template set-up is left as an exercise to the reader. Somehow, either via PXE, embedded bootstrap scripts, or some other method -- clones of VM templates need to be able to set their hostname, register themselves in your DNS, and be resolvable by the vmpooler application after completing the clone task and booting up.

API and Dashboard

vmpooler provides an API and web front-end (dashboard) on port :4567. See the provided YAML configuration example, vmpooler.yaml.example, to specify an alternative port to listen on.

API

vmpooler provides a REST API for VM management. The following examples use curl for communication.

VM operations

GET /vm

Retrieve a list of available VM pools.

$ curl --url vmpooler.company.com/vm

[
  "debian-7-i386",
  "debian-7-x86_64"
]

POST /vm

Useful for batch operations; post JSON (see format below), get back VMs.

$ curl -d '{"debian-7-i386":"2","debian-7-x86_64":"1"}' --url vmpooler.company.com/vm

{
  "ok": true,
  "debian-7-i386": {
    "hostname": [
      "o41xtodlvnvu5cw",
      "khirruvwfjlmx3y"
    ]
  },
  "debian-7-x86_64": {
    "hostname": "y91qbrpbfj6d13q"
  }
}

POST /vm/<pool>

Check-out a VM or VMs.

$ curl -d --url vmpooler.company.com/vm/debian-7-i386

{
  "ok": true,
  "debian-7-i386": {
    "hostname": "fq6qlpjlsskycq6"
  }
}

Multiple VMs can be requested by using multiple query parameters in the URL:

$ curl -d --url vmpooler.company.com/vm/debian-7-i386+debian-7-i386+debian-7-x86_64

{
  "ok": true,
  "debian-7-i386": {
    "hostname": [
      "sc0o4xqtodlul5w",
      "4m4dkhqiufnjmxy"
    ]
  },
  "debian-7-x86_64": {
    "hostname": "zb91y9qbrbf6d3q"
  }
}

GET /vm/<hostname>

Query a checked-out VM.

$ curl --url vmpooler.company.com/vm/pxpmtoonx7fiqg6

{
  "ok": true,
  "pxpmtoonx7fiqg6": {
    "template": "centos-6-x86_64",
    "lifetime": 12,
    "running": 3,
    "domain": "company.com"
  }
}

PUT /vm/<hostname>

Modify a checked-out VM.

The following are valid PUT parameters and their required data structures:

parameter	description	required structure
lifetime	VM TTL (in hours)	integer
tags	free-form VM tagging	hash

Any modifications can be verified using the GET /vm/<hostname> endpoint.

$ curl -X PUT -d '{"lifetime":"2"}' --url vmpooler.company.com/vm/fq6qlpjlsskycq6

{
  "ok": true
}

$ curl -X PUT -d '{"tags":{"department":"engineering","user":"sschneid"}}' --url vmpooler.company.com/vm/fq6qlpjlsskycq6

{
  "ok": true
}

DELETE /vm/<hostname>

Schedule a checked-out VM for deletion.

$ curl -X DELETE --url vmpooler.company.com/vm/fq6qlpjlsskycq6

{
  "ok": true
}

Status and metrics

GET /status

A "live" status endpoint, representing the current state of the service.

$ curl --url vmpooler.company.com/status

{
  "capacity": {
    "current": 716,
    "total": 717,
    "percent": 99.9
  },
  "clone": {
    "duration": {
      "average": 8.8,
      "min": 2.79,
      "max": 69.76
    },
    "count": {
      "total": 1779
    }
  },
  "queue": {
    "pending": 1,
    "cloning": 0,
    "booting": 1,
    "ready": 716,
    "running": 142,
    "completed": 0,
    "total": 859
  },
  "status": {
    "ok": true,
    "message": "Battle station fully armed and operational."
  }
}

If there are empty pools, the "status" section will convey this:

  "status": {
    "ok": false,
    "message": "Found 2 empty pools.",
    "empty": [
      "centos-6-x86_64",
      "debian-7-x86_64"
    ]
  }

GET /summary[?from=YYYY-MM-DD[&to=YYYY-MM-DD]]

Returns a summary, or report, for the timespan between from and to (inclusive) parameters. The response includes both an overall and daily view of tracked metrics, such as boot and cloning durations.

Any omitted query parameter will default to now/today. A request without any parameters will result in the current day's summary.

$ curl --url vmpooler.company.com/summary

{
  "boot": {
    "duration": {
      "average": 106.6,
      "min": 83.09,
      "max": 121.06,
      "total": 639.36,
    },
    "count": {
      "average": 6,
      "min": 6,
      "max": 6,
      "total": 6,
    }
  },
  "clone": {
    "duration": {
      "average": 4.6,
      "min": 2.78,
      "max": 8.1,
      "total": 63.94,
    },
    "count": {
      "average": 14,
      "min": 14,
      "max": 14,
      "total": 14,
    }
  },
  "daily": [
    {
      "date": "2015-03-11",
      "boot": {
        "duration": {
          "average": 106.6,
          "min": 83.09,
          "max": 121.06,
          "total": 639.36
        },
        "count": {
          "total": 6
        }
      },
      "clone": {
        "duration": {
          "average": 4.6,
          "min": 2.78,
          "max": 8.1,
          "total": 63.94
        },
        "count": {
          "total": 14
        }
      }
    }
  ]
}

$ curl -G -d 'from=2015-03-10' -d 'to=2015-03-11' --url vmpooler.company.com/summary

{
  "boot": {...},
  "clone": {...},
  "daily": [
    {
      "date": "2015-03-10",
      "boot": {
        "duration": {
          "average": 0,
          "min": 0,
          "max": 0,
          "total": 0
        },
        "count": {
          "total": 0
        }
      },
      "clone": {
        "duration": {
          "average": 0,
          "min": 0,
          "max": 0,
          "total": 0
        },
        "count": {
          "total": 0
        }
      }
    },
    {
      "date": "2015-03-11",
      "boot": {
        "duration": {
          "average": 106.6,
          "min": 83.09,
          "max": 121.06,
          "total": 639.36
        },
        "count": {
          "total": 6
        }
      },
      "clone": {
        "duration": {
          "average": 4.6,
          "min": 2.78,
          "max": 8.1,
          "total": 63.94
        },
        "count": {
          "total": 14
        }
      }
    }
  ]
}

Dashboard

A dashboard is provided to offer real-time statistics and historical graphs. It looks like this in a large installation on a fairly busy day:

Graphite is required for historical data retrieval. See the provided YAML configuration example, vmpooler.yaml.example, for details.

License

vmpooler is distributed under the Apache License, Version 2.0. See the LICENSE file for more details.