Files
patroni/.github/workflows/install_deps.py
T
Alexander KukushkinandGitHub c7173aadd7 Failover logical slots (#1820)
Effectively, this PR consists of a few changes:

1. The easy part:
  In case of permanent logical slots are defined in the global configuration, Patroni on the primary will not only create them, but also periodically update DCS with the current values of `confirmed_flush_lsn` for all these slots.
  In order to reduce the number of interactions with DCS the new `/status` key was introduced. It will contain the json object with `optime` and `slots` keys. For backward compatibility the `/optime/leader` will be updated if there are members with old Patroni in the cluster.

2. The tricky part:
  On replicas that are eligible for a failover, Patroni creates the logical replication slot by copying the slot file from the primary and restarting the replica. In order to copy the slot file Patroni opens a connection to the primary with `rewind` or `superuser` credentials and calls `pg_read_binary_file()`  function.
  When the logical slot already exists on the replica Patroni periodically calls `pg_replication_slot_advance()` function, which allows moving the slot forward.

3. Additional requirements:
  In order to ensure that primary doesn't cleanup tuples from pg_catalog that are required for logical decoding, Patroni enables `hot_standby_feedback` on replicas with logical slots and on cascading replicas if they are used for streaming by replicas with logical slots.

4. When logical slots are copied from to the replica there is a timeframe when it could be not safe to use them after promotion. Right now there is no protection from promoting such a replica. But, Patroni will show the warning with names of the slots that might be not safe to use.

Compatibility.
The `pg_replication_slot_advance()` function is only available starting from PostgreSQL 11. For older Postgres versions Patroni will refuse to create the logical slot on the primary.

The old "permanent slots" feature, which creates logical slots right after promotion and before allowing connections, was removed.

Close: https://github.com/zalando/patroni/issues/1749
2021-03-25 16:18:23 +01:00

183 lines
5.6 KiB
Python

import inspect
import os
import shutil
import subprocess
import stat
import sys
import tarfile
import time
import zipfile
def install_requirements(what):
old_path = sys.path[:]
w = os.path.join(os.getcwd(), os.path.dirname(inspect.getfile(inspect.currentframe())))
sys.path.insert(0, os.path.dirname(os.path.dirname(w)))
try:
from setup import EXTRAS_REQUIRE, read
finally:
sys.path = old_path
requirements = ['mock>=2.0.0', 'flake8', 'pytest', 'pytest-cov'] if what == 'all' else ['behave']
requirements += ['psycopg2-binary', 'coverage']
for r in read('requirements.txt').split('\n'):
r = r.strip()
if r != '':
extras = {e for e, v in EXTRAS_REQUIRE.items() if v and r.startswith(v[0])}
if not extras or what == 'all' or what in extras:
requirements.append(r)
subprocess.call([sys.executable, '-m', 'pip', 'install', '--upgrade', 'pip'])
r = subprocess.call([sys.executable, '-m', 'pip', 'install'] + requirements)
s = subprocess.call([sys.executable, '-m', 'pip', 'install', '--upgrade', 'setuptools'])
return s | r
def install_packages(what):
packages = {
'zookeeper': ['zookeeper', 'zookeeper-bin', 'zookeeperd'],
'consul': ['consul'],
}
packages['exhibitor'] = packages['zookeeper']
packages = packages.get(what, [])
ver = str({'etcd': '9.6', 'etcd3': '13', 'consul': 12, 'exhibitor': 11, 'kubernetes': 13, 'raft': 12}.get(what))
subprocess.call(['sudo', 'apt-get', 'update', '-y'])
return subprocess.call(['sudo', 'apt-get', 'install', '-y', 'postgresql-' + ver, 'expect-dev', 'wget'] + packages)
def get_file(url, name):
try:
from urllib.request import urlretrieve
except ImportError:
from urllib import urlretrieve
print('Downloading ' + url)
urlretrieve(url, name)
def untar(archive, name):
with tarfile.open(archive) as tar:
f = tar.extractfile(name)
dest = os.path.basename(name)
with open(dest, 'wb') as d:
shutil.copyfileobj(f, d)
return dest
def unzip(archive, name):
with zipfile.ZipFile(archive, 'r') as z:
name = z.extract(name)
dest = os.path.basename(name)
shutil.move(name, dest)
return dest
def unzip_all(archive):
print('Extracting ' + archive)
with zipfile.ZipFile(archive, 'r') as z:
z.extractall()
def chmod_755(name):
os.chmod(name, stat.S_IRUSR | stat.S_IWUSR | stat.S_IXUSR |
stat.S_IRGRP | stat.S_IXGRP | stat.S_IROTH | stat.S_IXOTH)
def unpack(archive, name):
print('Extracting {0} from {1}'.format(name, archive))
func = unzip if archive.endswith('.zip') else untar
name = func(archive, name)
chmod_755(name)
return name
def install_etcd():
version = os.environ.get('ETCDVERSION', '3.3.13')
platform = {'linux2': 'linux', 'win32': 'windows', 'cygwin': 'windows'}.get(sys.platform, sys.platform)
dirname = 'etcd-v{0}-{1}-amd64'.format(version, platform)
ext = 'tar.gz' if platform == 'linux' else 'zip'
name = '{0}.{1}'.format(dirname, ext)
url = 'https://github.com/etcd-io/etcd/releases/download/v{0}/{1}'.format(version, name)
get_file(url, name)
ext = '.exe' if platform == 'windows' else ''
return int(unpack(name, '{0}/etcd{1}'.format(dirname, ext)) is None)
def install_postgres():
version = os.environ.get('PGVERSION', '12.1-1')
platform = {'darwin': 'osx', 'win32': 'windows-x64', 'cygwin': 'windows-x64'}[sys.platform]
name = 'postgresql-{0}-{1}-binaries.zip'.format(version, platform)
get_file('http://get.enterprisedb.com/postgresql/' + name, name)
unzip_all(name)
bin_dir = os.path.join('pgsql', 'bin')
for f in os.listdir(bin_dir):
chmod_755(os.path.join(bin_dir, f))
subprocess.call(['pgsql/bin/postgres', '-V'])
return 0
def setup_kubernetes():
get_file('https://storage.googleapis.com/minikube/k8sReleases/v1.7.0/localkube-linux-amd64', 'localkube')
chmod_755('localkube')
devnull = open(os.devnull, 'w')
subprocess.Popen(['sudo', 'nohup', './localkube', '--logtostderr=true', '--enable-dns=false'],
stdout=devnull, stderr=devnull)
for _ in range(0, 120):
if subprocess.call(['wget', '-qO', '-', 'http://127.0.0.1:8080/'], stdout=devnull, stderr=devnull) == 0:
break
time.sleep(1)
else:
print('localkube did not start')
return 1
subprocess.call('sudo chmod 644 /var/lib/localkube/certs/*', shell=True)
print('Set up .kube/config')
kube = os.path.join(os.path.expanduser('~'), '.kube')
os.makedirs(kube)
with open(os.path.join(kube, 'config'), 'w') as f:
f.write("""apiVersion: v1
clusters:
- cluster:
certificate-authority: /var/lib/localkube/certs/ca.crt
server: https://127.0.0.1:8443
name: local
contexts:
- context:
cluster: local
user: myself
name: local
current-context: local
kind: Config
preferences: {}
users:
- name: myself
user:
client-certificate: /var/lib/localkube/certs/apiserver.crt
client-key: /var/lib/localkube/certs/apiserver.key
""")
return 0
def main():
what = os.environ.get('DCS', sys.argv[1] if len(sys.argv) > 1 else 'all')
if what != 'all':
if sys.platform.startswith('linux'):
r = install_packages(what)
if r == 0 and what == 'kubernetes':
r = setup_kubernetes()
else:
r = install_postgres()
if r == 0 and what.startswith('etcd'):
r = install_etcd()
if r != 0:
return r
return install_requirements(what)
if __name__ == '__main__':
sys.exit(main())