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'''Functions related to charm storage maintenance'''
import glob
import os
import subprocess
# pylint can't find the modules # pylint: disable=F0401
from charmhelpers.contrib.storage.linux import utils as Storage
from charmhelpers.core import (
fstab,
hookenv,
host,
)
# pylint: enable=F0401
LOG = hookenv.log
SERVICE = 'ubuntu-repository-cache'
def setup():
'''Set up storage for the charm'''
config = hookenv.config()
_setup_ephemeral(config['ephemeral-devices'])
try:
primary_mount = config['ephemeral-mounts'][0]
secondary_mounts = config['ephemeral-mounts'][1:]
except KeyError:
primary_mount = '/'.join(('/srv', hookenv.service_name()))
secondary_mounts = []
# Make file system directories
LOG('Creating filesystem entries for %s' % SERVICE)
_mkdir(primary_mount, perms=0o775)
_setup_metadata_path(primary_mount)
_setup_packages_path(primary_mount, secondary_mounts)
def _setup_metadata_path(rootdir):
'''Create the directory structure for metadata served by apache'''
config = hookenv.config()
apache_root = config['apache-root'] = '/'.join((rootdir, 'apache'))
# Apache serves from www/ and metadata is in data/
_mkdir(apache_root, owner='www-data', group='www-data', perms=0o775)
_mkdir('/'.join((apache_root, 'www')),
owner='www-data', group='www-data', perms=0o775)
_mkdir('/'.join((apache_root, 'data')),
owner='www-data', group='www-data', perms=0o775)
host.symlink('/'.join((apache_root, 'data', 'ubuntu_active')),
'/'.join((apache_root, 'www', 'ubuntu')))
def _setup_packages_path(primary_mount, secondary_mounts):
'''Create the squid cache directorys for package caches.
The config 'squid-disk-caches' is populated with the path to each
cache directory and the maximum space available, in MB, for that mount.
In this list the primary device is added last and the maximum space
calculation reserves room for the OS and metadata mirror.
The order of the list is important because squid disk caches will
be sized based on system memory, so some available disk space may
not be used. In that case, having the mount used for metadata
mirrors last would let any additional space be used for that.
'''
config = hookenv.config()
config['squid-disk-caches'] = []
for mnt in secondary_mounts:
squid_cache = '/'.join((mnt, 'squid'))
_mkdir(squid_cache, owner='proxy', group='proxy', perms=0o770)
max_size = _disk_free(squid_cache) * 0.95
if max_size:
config['squid-disk-caches'].append([squid_cache, max_size])
# Add the primary mount last for squid. This allocates it last
# and saves additional space for metadata mirrors
squid_cache = '/'.join((primary_mount, 'squid'))
_mkdir(squid_cache, owner='proxy', group='proxy', perms=0o770)
max_size = _disk_free(squid_cache)
# Reserve 8GB for metadata and 4GB for the OS
reserve = 8192 + 4092
if max_size < reserve:
LOG('Less than {}MB disk free @ {} for mirror.'.format(reserve,
primary_mount),
hookenv.ERROR)
else:
max_size = max_size - reserve
config['squid-disk-caches'].append([squid_cache, max_size])
config.save()
def _setup_ephemeral(devices=None):
'''Formats and mounts ephemeral devices
Each ephemeral device is formated with ext4 and provided a label
of the format '<service_name>_<#>'
Devices are mounted at:
/srv/<service_name>/ephemeral/<#>
An fstab entry is added for each device to ensure the device is
mounted on reboot.
'''
if not devices:
LOG('No ephemeral devices provided')
return
base_dir = '/'.join(('/srv', hookenv.service_name()))
_mkdir(base_dir, perms=0o775)
ephemeral_dir = '/'.join((base_dir, 'ephemeral'))
_mkdir(ephemeral_dir, perms=0o775)
config = hookenv.config()
config['ephemeral-mounts'] = []
devno = 0
for dev in devices.split(','):
dev = dev.strip()
LOG('Configuring ephemeral device {}.'.format(dev), hookenv.DEBUG)
if not Storage.is_block_device(dev):
LOG('%s is not a block device, skipping' % dev, hookenv.ERROR)
continue
partitions = glob.glob(dev + '*').remove(dev) or []
for part in partitions:
if Storage.is_device_mounted(part):
LOG('Ephemeral device had a mounted partition %s skipping' %
part, hookenv.ERROR)
continue
if Storage.is_device_mounted(dev):
LOG('Unmounting %s' % dev)
host.umount(dev)
label = '_'.join(('urc', str(devno)))
mountpoint = '/'.join((ephemeral_dir, str(devno)))
Storage.zap_disk(dev)
subprocess.check_call(['mkfs', '-F', '-t', 'ext4', '-L', label, dev])
# Remove any existing fstab entry
ftab = fstab.Fstab()
entry = ftab.get_entry_by_attr('device', dev)
if entry:
ftab.remove_entry(entry)
# Add to fstab by label, not device name
_mkdir(mountpoint, perms=0o775)
devname = '='.join(('LABEL', label))
ftab.add_entry(fstab.Fstab.Entry(devname, mountpoint, 'ext4',
options=None))
ftab.close()
subprocess.check_call(['mount', mountpoint])
os.chmod(mountpoint, 0o775)
config['ephemeral-mounts'].append(mountpoint)
devno += 1
LOG('Ephemeral storage mounted @ {}'.format(config['ephemeral-mounts']),
hookenv.DEBUG)
config.save()
def _mkdir(path, owner='root', group='root', perms=0o555, force=False):
'''Make directories recursively with a umask=0o000.
This storage module makes calls to mkdir repeatedly with permissions
that include group write permission. This would be masked by the
default 0o022 umask. This simple helper function will clear
the umask prior to calling host.mkdir and then restore it when done.
'''
prev_umask = os.umask(0o000)
host.mkdir(path, owner=owner, group=group, perms=perms, force=force)
os.umask(prev_umask)
def _disk_free(path):
'''Return disk space free, in MB, for the specified path'''
output = subprocess.check_output(['df', '-BM', path]).decode().split('\n')
_, _, _, avail, _, _ = output[1].split()
LOG('disk free for {} is {}MB'.format(path, avail), hookenv.DEBUG)
return int(avail.rstrip('M'))
def update_checks(nrpe_config):
'''Update nagios check for ephemeral storage space if present'''
config = hookenv.config()
try:
LOG('Adding check for ephemeral stoage {}'.format(
config['ephemeral-mounts']),
hookenv.DEBUG)
except KeyError:
LOG('No checks added for ephemeral storage', hookenv.DEBUG)
return
nrpe_config.add_check(
shortname='disks-ephemeral',
description='disk space on ephemeral volumes',
check_cmd='check_disk -w 15 -c 5 -r '
'^/srv/ubuntu-repository-cache/ephemeral/[0-9].*$',
)
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