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#!/usr/bin/env python |
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# |
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# Copyright (C) 2011 Greek Research and Technology Network |
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# |
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# This program is free software; you can redistribute it and/or modify |
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# it under the terms of the GNU General Public License as published by |
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# the Free Software Foundation; either version 2 of the License, or |
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# (at your option) any later version. |
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# |
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# This program is distributed in the hope that it will be useful, but |
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# WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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# General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with this program; if not, write to the Free Software |
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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# 02110-1301, USA. |
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|
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"""Map an existing rbd Image to a block device |
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|
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This program maps an existing rbd Image to a block device |
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e.g. /dev/rbd{X} and returns the device path. If the mapping |
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already exists, it returns the corresponding device path. |
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|
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It takes it's input from environment variables. Specifically the |
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following variables should be present: |
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|
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- VOL_NAME: The name of the Image to map |
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- POOL: The RADOS pool in which the Image resides |
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|
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Returns the block device path (which maps the Image) as a string |
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upon success, or 1 upon failure |
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|
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""" |
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|
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import os |
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import sys |
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import re |
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|
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sys.path.insert(0, "/etc/ganeti/share") |
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|
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from ganeti import utils |
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|
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|
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def ReadEnv(): |
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"""Read the mandatory enviromental variables |
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|
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""" |
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name = os.getenv("VOL_NAME") |
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if name is None: |
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sys.stderr.write('The environment variable VOL_NAME is missing.\n') |
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return None |
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# pool = os.getenv("POOL") |
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pool = "rbd" |
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if pool is None: |
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sys.stderr.write('The environment variable POOL is missing.\n') |
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return None |
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|
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return (name, pool) |
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|
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|
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def main(): |
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env = ReadEnv() |
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if env is None: |
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sys.stderr.write('Wrong environment. Aborting...\n') |
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return 1 |
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|
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name, pool = env |
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|
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# Check if the mapping already exists |
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cmd1 = ["rbd", "showmapped"] |
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result = utils.RunCmd(cmd1) |
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if result.failed: |
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sys.stderr.write("rbd showmapped failed (%s): %s" % |
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(result.fail_reason, result.output)) |
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return 1 |
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else: |
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cmd2 = "echo '%s' | grep %s | grep %s" % (result.output, pool, name) |
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result = utils.RunCmd(cmd2) |
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if not result.failed: |
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# The mapping already exists. |
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# Parse the result and return the rbd device |
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try: |
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rbd_dev = re.search("(/dev/rbd\d+)", result.output).group(1) |
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except: |
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sys.stderr.write("The rbd mapping exists but couldn't parse " |
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"the result of rbd showmapped to find the " |
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"corresponding rbd block device (/dev/rbd*)") |
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return 1 |
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|
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#return str(rbd_dev) |
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sys.stdout.write("%s" % str(rbd_dev)) |
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sys.exit(0) |
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|
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else: |
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# The mapping doesn't exist. Create it |
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cmd = ["rbd", "map", "-p", "%s" % pool, "%s" % name] |
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result = utils.RunCmd(cmd) |
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if result.failed: |
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sys.stderr.write("rbd map failed (%s): %s" % |
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(result.fail_reason, result.output)) |
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return 1 |
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# Use rbd showmapped again to find the rbd device |
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# the image was mapped to |
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cmd3 = "rbd showmapped | grep %s | grep %s" % (pool, name) |
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result = utils.RunCmd(cmd3) |
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if result.failed: |
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sys.stderr.write("Can't find mapped device. " |
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"rbd showmapped failed (%s): %s" % |
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(result.fail_reason, result.output)) |
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return 1 |
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try: |
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rbd_dev = re.search("(/dev/rbd\d+)", result.output).group(1) |
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except: |
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sys.stderr.write("The rbd mapping was created succesfully, but " |
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"couldn't parse the result of rbd showmapped to " |
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"find the corresponding rbd block device " |
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"(/dev/rbd*)") |
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return 1 |
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|
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# The device was successfully mapped. Return it |
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#return str(rbd_dev) |
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sys.stdout.write("%s" % str(rbd_dev)) |
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sys.exit(0) |
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|
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if __name__ == "__main__": |
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sys.exit(main()) |