def create_cluster():
'''Sets the postgresql.cluster.created state.'''
assert not os.path.exists(postgresql.postgresql_conf_path()), \
'inhibit_default_cluster_creation() failed'
assert not os.path.exists(postgresql.data_dir())
postgresql.create_cluster()
reactive.set_state('postgresql.cluster.created')
def remount():
if reactive.is_state('postgresql.cluster.is_running'):
# Attempting this while PostgreSQL is live would be really, really bad.
service.stop()
old_data_dir = postgresql.data_dir()
new_data_dir = os.path.join(external_volume_mount, 'postgresql',
postgresql.version(), 'main')
backup_data_dir = '{}-{}'.format(old_data_dir, int(time.time()))
if os.path.isdir(new_data_dir):
hookenv.log('Remounting existing database at {}'.format(new_data_dir),
WARNING)
else:
status_set('maintenance',
'Migrating data from {} to {}'.format(old_data_dir,
new_data_dir))
helpers.makedirs(new_data_dir, mode=0o770,
user='******', group='postgres')
try:
rsync_cmd = ['rsync', '-av',
old_data_dir + '/',
new_data_dir + '/']
hookenv.log('Running {}'.format(' '.join(rsync_cmd)), DEBUG)
subprocess.check_call(rsync_cmd)
except subprocess.CalledProcessError:
status_set('blocked',
'Failed to sync data from {} to {}'
''.format(old_data_dir, new_data_dir))
return
os.replace(old_data_dir, backup_data_dir)
os.symlink(new_data_dir, old_data_dir)
fix_perms(new_data_dir)
reactive.remove_state('postgresql.storage.needs_remount')
def test_simple_paths(self, version):
# We have a pile of trivial helpers to get directory and file
# paths. We use these for consistency and ease of mocking.
version.return_value = "9.9"
self.assertEqual(postgresql.config_dir(), "/etc/postgresql/9.9/main")
self.assertEqual(postgresql.data_dir(), "/var/lib/postgresql/9.9/main")
self.assertEqual(postgresql.postgresql_conf_path(), "/etc/postgresql/9.9/main/postgresql.conf")
self.assertEqual(postgresql.pg_hba_conf_path(), "/etc/postgresql/9.9/main/pg_hba.conf")
self.assertEqual(postgresql.pg_ident_conf_path(), "/etc/postgresql/9.9/main/pg_ident.conf")
self.assertEqual(postgresql.recovery_conf_path(), "/var/lib/postgresql/9.9/main/recovery.conf")
self.assertEqual(postgresql.pg_ctl_path(), "/usr/lib/postgresql/9.9/bin/pg_ctl")
self.assertEqual(postgresql.postgres_path(), "/usr/lib/postgresql/9.9/bin/postgres")
def test_simple_paths(self, version):
# We have a pile of trivial helpers to get directory and file
# paths. We use these for consistency and ease of mocking.
version.return_value = '9.9'
self.assertEqual(postgresql.config_dir(), '/etc/postgresql/9.9/main')
self.assertEqual(postgresql.data_dir(), '/var/lib/postgresql/9.9/main')
self.assertEqual(postgresql.postgresql_conf_path(),
'/etc/postgresql/9.9/main/postgresql.conf')
self.assertEqual(postgresql.pg_hba_conf_path(),
'/etc/postgresql/9.9/main/pg_hba.conf')
self.assertEqual(postgresql.pg_ident_conf_path(),
'/etc/postgresql/9.9/main/pg_ident.conf')
self.assertEqual(postgresql.recovery_conf_path(),
'/var/lib/postgresql/9.9/main/recovery.conf')
self.assertEqual(postgresql.pg_ctl_path(),
'/usr/lib/postgresql/9.9/bin/pg_ctl')
self.assertEqual(postgresql.postgres_path(),
'/usr/lib/postgresql/9.9/bin/postgres')
def migrate_pgdata():
'''
Copy the data from /var/lib/postgresql/9.x/main to the
new path and replace the original PGDATA with a symlink.
Note that the original may already be a symlink, either from
the block storage broker or manual changes by admins.
'''
if reactive.is_state('postgresql.cluster.is_running'):
# Attempting this while PostgreSQL is live would be really, really bad.
service.stop()
old_data_dir = postgresql.data_dir()
new_data_dir = unitdata.kv().get(pgdata_path_key)
backup_data_dir = '{}-{}'.format(old_data_dir, int(time.time()))
if os.path.isdir(new_data_dir):
# This never happens with Juju storage, at least with 2.0,
# because we have no way of reusing old partitions.
hookenv.log('Remounting existing database at {}'.format(new_data_dir),
WARNING)
else:
status_set('maintenance',
'Migrating data from {} to {}'.format(old_data_dir,
new_data_dir))
helpers.makedirs(new_data_dir, mode=0o770,
user='******', group='postgres')
try:
rsync_cmd = ['rsync', '-av',
old_data_dir + '/',
new_data_dir + '/']
hookenv.log('Running {}'.format(' '.join(rsync_cmd)), DEBUG)
subprocess.check_call(rsync_cmd, universal_newlines=True)
except subprocess.CalledProcessError:
status_set('blocked',
'Failed to sync data from {} to {}'
''.format(old_data_dir, new_data_dir))
return
os.replace(old_data_dir, backup_data_dir)
os.symlink(new_data_dir, old_data_dir)
fix_perms(new_data_dir)
reactive.set_state('postgresql.storage.pgdata.migrated')
def main():
if not (reactive.is_state("postgresql.cluster.created") or reactive.is_state("postgresql.cluster.initial-check")):
# We need to check for existance of an existing database,
# before the main PostgreSQL package has been installed.
# If there is one, abort rather than risk destroying data.
# We need to do this here, as the apt layer may pull in
# the main PostgreSQL package through dependencies, per
# lp:1749284
if os.path.exists(postgresql.postgresql_conf_path()):
hookenv.status_set(
"blocked",
"PostgreSQL config from previous install found at {}".format(postgresql.postgresql_conf_path()),
)
elif os.path.exists(postgresql.data_dir()):
hookenv.status_set(
"blocked",
"PostgreSQL database from previous install found at {}".format(postgresql.postgresql.data_dir()),
)
else:
hookenv.log("No pre-existing PostgreSQL database found")
reactive.set_state("postgresql.cluster.initial-check")
# Don't trust this state from the last hook. Daemons may have
# crashed and servers rebooted since then.
if reactive.is_state("postgresql.cluster.created"):
try:
reactive.toggle_state("postgresql.cluster.is_running", postgresql.is_running())
except subprocess.CalledProcessError as x:
if not reactive.is_state("workloadstatus.blocked"):
status_set(
"blocked",
"Local PostgreSQL cluster is corrupt: {}".format(x.stderr),
)
# Reconfigure PostgreSQL. While we don't strictly speaking need
# to do this every hook, we do need to do this almost every hook,
# since even things like the number of peers or number of clients
# can affect minimum viable configuration settings.
reactive.remove_state("postgresql.cluster.configured")
log_states() # Debug noise.
def remount():
if reactive.is_state("postgresql.cluster.is_running"):
# Attempting this while PostgreSQL is live would be really, really bad.
service.stop()
old_data_dir = postgresql.data_dir()
new_data_dir = os.path.join(external_volume_mount, "postgresql",
postgresql.version(), "main")
backup_data_dir = "{}-{}".format(old_data_dir, int(time.time()))
if os.path.isdir(new_data_dir):
hookenv.log("Remounting existing database at {}".format(new_data_dir),
WARNING)
else:
status_set(
"maintenance",
"Migrating data from {} to {}".format(old_data_dir, new_data_dir),
)
helpers.makedirs(new_data_dir,
mode=0o770,
user="******",
group="postgres")
try:
rsync_cmd = [
"rsync", "-av", old_data_dir + "/", new_data_dir + "/"
]
hookenv.log("Running {}".format(" ".join(rsync_cmd)), DEBUG)
subprocess.check_call(rsync_cmd)
except subprocess.CalledProcessError:
status_set(
"blocked",
"Failed to sync data from {} to {}"
"".format(old_data_dir, new_data_dir),
)
return
os.replace(old_data_dir, backup_data_dir)
os.symlink(new_data_dir, old_data_dir)
fix_perms(new_data_dir)
reactive.remove_state("postgresql.storage.needs_remount")
def attach():
mount = hookenv.storage_get()['location']
pgdata = os.path.join(mount, postgresql.version(), 'main')
unitdata.kv().set(pgdata_mount_key, mount)
unitdata.kv().set(pgdata_path_key, pgdata)
hookenv.log('PGDATA storage attached at {}'.format(mount))
# Never happens with Juju 2.0 as we can't reuse an old mount. This
# check is here for the future.
existingdb = os.path.exists(pgdata)
required_space = shutil.disk_usage(postgresql.data_dir()).used
free_space = shutil.disk_usage(mount).free
if required_space > free_space and not existingdb:
hookenv.status_set('blocked',
'Not enough free space in pgdata storage')
else:
apt.queue_install(['rsync'])
coordinator.acquire('restart')
reactive.set_state('postgresql.storage.pgdata.attached')
def needs_remount():
mounted = os.path.isdir(external_volume_mount)
linked = os.path.islink(postgresql.data_dir())
return mounted and not linked
def wal_e_backup_command():
return 'envdir {} wal-e backup-push {}'.format(wal_e_env_dir(),
postgresql.data_dir())
def wal_e_restore():
reactive.remove_state("action.wal-e-restore")
params = hookenv.action_get()
backup = params["backup-name"].strip().replace("-", "_")
storage_uri = params["storage-uri"].strip()
ship_uri = hookenv.config().get("wal_e_storage_uri")
if storage_uri == ship_uri:
hookenv.action_fail(
"The storage-uri parameter is identical to "
"the wal_e_storage_uri config setting. Your "
"restoration source cannot be the same as the "
"folder you are archiving too to avoid corrupting "
"the backups."
)
return
if not params["confirm"]:
m = "Recovery from {}.".format(storage_uri)
if ship_uri:
m += "\nContents of {} will be destroyed.".format(ship_uri)
m += "\nExisting local database will be destroyed."
m += "\nRerun action with 'confirm=true' to proceed."
hookenv.action_set({"info": m})
return
with tempfile.TemporaryDirectory(prefix="wal-e", suffix="envdir") as envdir:
update_wal_e_env_dir(envdir, storage_uri)
# Confirm there is a backup to restore
backups = wal_e_list_backups(envdir)
if not backups:
hookenv.action_fail("No backups found at {}".format(storage_uri))
return
if backup != "LATEST" and backup not in (b["name"] for b in backups):
hookenv.action_fail("Backup {} not found".format(backup))
return
# Shutdown PostgreSQL. Note we want this action to run synchronously,
# so there is no opportunity to ask permission from the leader. If
# there are other units cloning this database, those clone operations
# will fail. Which seems preferable to blocking a recovery operation
# in any case, because if we are doing disaster recovery we generally
# want to do it right now.
status_set("maintenance", "Stopping PostgreSQL for backup restoration")
postgresql.stop()
# Trash the existing database. Its dangerous to do this first, but
# we probably need the space.
data_dir = postgresql.data_dir() # May be a symlink
for content in os.listdir(data_dir):
cpath = os.path.join(data_dir, content)
if os.path.isdir(cpath) and not os.path.islink(cpath):
shutil.rmtree(cpath)
else:
os.remove(cpath)
# WAL-E recover
status_set("maintenance", "Restoring backup {}".format(backup))
wal_e_run(["backup-fetch", data_dir, backup], envdir=envdir)
# Create recovery.conf to complete recovery
is_master = reactive.is_state("postgresql.replication.is_master")
standby_mode = "off" if is_master else "on"
if params.get("target-time"):
target_time = "recovery_target_time='{}'" "".format(params["target-time"])
else:
target_time = ""
target_action = "promote" if is_master else "shutdown"
immediate = "" if is_master else "recovery_target='immediate'"
helpers.write(
postgresql.recovery_conf_path(),
dedent(
"""\
# Managed by Juju. PITR in progress.
standby_mode = {}
restore_command='{}'
recovery_target_timeline = {}
recovery_target_action = {}
{}
{}
"""
).format(
standby_mode,
wal_e_restore_command(envdir=envdir),
params["target-timeline"],
target_action,
target_time,
immediate,
),
mode=0o600,
user="******",
group="postgres",
)
# Avoid circular import. We could also avoid the import entirely
# with a sufficiently complex set of handlers in the replication
# module, but that seems to be a worse solution. Better to break
# out this action into a separate module.
from reactive.postgresql import replication
if is_master:
if ship_uri:
# If master, trash the configured wal-e storage. This may
# contain WAL and backups from the old cluster which will
# conflict with the new cluster. Hopefully it does not
# contain anything important, because we have no way to
# prompt the user for confirmation.
wal_e_run(["delete", "--confirm", "everything"])
# Then, wait for recovery and promotion.
postgresql.start()
con = postgresql.connect()
cur = con.cursor()
while True:
if postgresql.has_version("10"):
cur.execute(
"""SELECT pg_is_in_recovery(),
pg_last_wal_replay_lsn()"""
)
else:
cur.execute(
"""SELECT pg_is_in_recovery(),
pg_last_xlog_replay_location()"""
)
in_rec, loc = cur.fetchone()
if not in_rec:
break
status_set("maintenance", "Recovery at {}".format(loc))
time.sleep(10)
else:
# If standby, startup and wait for recovery to complete and
# shutdown.
status_set("maintenance", "Recovery")
# Startup might shutdown immediately and look like a failure.
postgresql.start(ignore_failure=True)
# No recovery point status yet for standbys, as we would need
# to handle connection failures when the DB shuts down. We
# should do this.
while postgresql.is_running():
time.sleep(5)
replication.update_recovery_conf(follow=replication.get_master())
# Reactive handlers will deal with the rest of the cleanup.
# eg. ensuring required users and roles exist
replication.update_replication_states()
reactive.remove_state("postgresql.cluster.configured")
reactive.toggle_state("postgresql.cluster.is_running", postgresql.is_running())
reactive.remove_state("postgresql.nagios.user_ensured")
reactive.remove_state("postgresql.replication.replication_user_created")
reactive.remove_state("postgresql.client.published")
def wal_e_backup_command():
return "/snap/bin/wal-e.envdir {} /snap/bin/wal-e backup-push {}".format(wal_e_env_dir(), postgresql.data_dir())
def clone_master():
master = get_master()
peer_rel = helpers.get_peer_relation()
master_relinfo = peer_rel[master]
# Be paranoid since we are about to destroy data.
assert not reactive.helpers.is_state("postgresql.replication.is_master")
assert not reactive.helpers.is_state("postgresql.cluster.is_running")
# We use realpath on data_dir as it may have been replaced with
# a symbolic link, so we empty and recreate the actual directory
# and the links remain in place.
data_dir = os.path.realpath(postgresql.data_dir())
if os.path.exists(data_dir):
hookenv.log("Removing {} in preparation for clone".format(data_dir))
shutil.rmtree(data_dir)
helpers.makedirs(data_dir, mode=0o700, user="******", group="postgres")
if postgresql.has_version("10"):
wal_method = "--wal-method=stream"
else:
wal_method = "--xlog-method=stream"
cmd = [
"sudo",
"-H", # -H needed to locate $HOME/.pgpass
"-u",
"postgres",
"pg_basebackup",
"-D",
postgresql.data_dir(),
"-h",
master_relinfo["host"],
"-p",
master_relinfo["port"],
"--checkpoint=fast",
"--progress",
wal_method,
"--no-password",
"--username=_juju_repl",
]
hookenv.log("Cloning {} with {}".format(master, " ".join(cmd)))
status_set("maintenance", "Cloning {}".format(master))
try:
# Switch to a directory the postgres user can access.
with helpers.switch_cwd("/tmp"):
subprocess.check_call(cmd, universal_newlines=True)
except subprocess.CalledProcessError as x:
hookenv.log("Clone failed with {}".format(x), ERROR)
# We failed, and the local cluster is broken.
status_set("blocked", "Failed to clone {}".format(master))
postgresql.drop_cluster()
reactive.remove_state("postgresql.cluster.configured")
reactive.remove_state("postgresql.cluster.created")
# Terminate. We need this hook to exit, rather than enter a loop.
raise SystemExit(0)
update_recovery_conf(follow=master)
reactive.set_state("postgresql.replication.cloned")
update_replication_states()
def needs_remount():
mounted = os.path.isdir(external_volume_mount)
linked = os.path.islink(postgresql.data_dir())
return mounted and not linked
