def register_readers(galera_cluster,
proxysql,
writer_hostgroup_id,
reader_hostgroup_id,
ignore_writer=None):
"""
Checks ProxySQL and Galera cluster and makes sure readers are registered.
:param galera_cluster: GaleraCluster instance.
:type galera_cluster: GaleraCluster
:param proxysql: ProxySQL instance
:type proxysql: ProxySQL
:param writer_hostgroup_id: Writer hostgroup_id
:type writer_hostgroup_id: int
:param reader_hostgroup_id: Reader hostgroup_id
:type reader_hostgroup_id: int
:param ignore_writer: Do not make this backend writer
:type ignore_writer: ProxySQLMySQLBackend
"""
LOG.debug('Registering readers')
try:
writer = proxysql.find_backends(writer_hostgroup_id)[0]
except ProxySQLBackendNotFound as err:
LOG.warn(err)
register_synced_backends(galera_cluster,
proxysql,
writer_hostgroup_id,
comment='Writer',
limit=1,
ignore_backend=ignore_writer)
writer = proxysql.find_backends(writer_hostgroup_id)[0]
try:
num_readers = 0
readers = proxysql.find_backends(reader_hostgroup_id)
for backend in readers:
LOG.debug('Comparing %s and %s', backend, writer)
if backend == writer:
# Don't register writer as reader for now
continue
LOG.debug('Do not match')
check_backend(backend, galera_cluster, proxysql,
reader_hostgroup_id, 'Reader')
num_readers += 1
if num_readers == 0:
LOG.warn('Did not register any readers')
check_backend(writer, galera_cluster, proxysql,
reader_hostgroup_id, 'Reader')
except ProxySQLBackendNotFound:
# If there are no readers , register writer as reader as well
LOG.debug('Reader backends not found')
writer_as_reader = writer
writer_as_reader.hostgroup_id = reader_hostgroup_id
register_synced_backends(galera_cluster,
proxysql,
reader_hostgroup_id,
comment='Reader',
ignore_backend=writer_as_reader)
def register_writer(galera_cluster,
proxysql,
writer_hostgroup_id,
reader_hostgroup_id,
ignore_writer=None):
"""
Checks ProxySQL and Galera cluster and makes sure there is one
healthy registered writer.
:param galera_cluster: GaleraCluster instance.
:type galera_cluster: GaleraCluster
:param proxysql: ProxySQL instance
:type proxysql: ProxySQL
:param writer_hostgroup_id: Writer hostgroup_id
:type writer_hostgroup_id: int
:param reader_hostgroup_id: Reader hostgroup_id
:type reader_hostgroup_id: int
:param ignore_writer: Do not make this backend writer
:type ignore_writer: ProxySQLMySQLBackend
"""
# Get writer backend. If doesn't exist - add.
# If exists - check state of respective Galera node.
# if the Galera node is not healthy - delete the backend and add a healthy
# one.
LOG.debug('Registering writers')
try:
for backend in proxysql.find_backends(writer_hostgroup_id):
check_backend(backend,
galera_cluster,
proxysql,
writer_hostgroup_id,
'Writer',
limit=1,
ignore_backend=ignore_writer,
recovered_hostgroup_id=reader_hostgroup_id,
recoverd_comment='Reader')
except ProxySQLBackendNotFound:
# add it
register_synced_backends(galera_cluster,
proxysql,
writer_hostgroup_id,
comment='Writer',
limit=1,
ignore_backend=ignore_writer)
try:
proxysql.find_backends(writer_hostgroup_id, BackendStatus.online)
except ProxySQLBackendNotFound:
LOG.warn('No writer backends were registered. '
'Will try to add previously ignored backends')
register_synced_backends(galera_cluster,
proxysql,
writer_hostgroup_id,
comment='Writer',
limit=1)
def check_backend(
backend,
galera_cluster,
proxysql,
hostgroup_id,
comment, # pylint: disable=too-many-arguments
limit=None,
ignore_backend=None,
recovered_hostgroup_id=None,
recoverd_comment=None):
"""
Check health of given backed and if necessary replace it.
:param backend: MySQL backend.
:type backend: ProxySQLMySQLBackend
:param galera_cluster: GaleraCluster instance.
:type galera_cluster: GaleraCluster
:param proxysql: ProxySQL instance.
:type proxysql: ProxySQL
:param hostgroup_id: Hostgroup_id which the backend belongs to.
:type hostgroup_id: int
:param comment: Comment to add to mysql_servers in ProxySQL
:param limit: Register not more than limit number of backends
:type limit: int
:param ignore_backend: Do not register this backend
:type ignore_backend: ProxySQLMySQLBackend
:param recovered_hostgroup_id: If backend recovers from OFFLINE_SOFT assign
it to this hostgroup_id. Default hostgroup_id.
:type recovered_hostgroup_id: int
:param recoverd_comment: If backend recovers from OFFLINE_SOFT set
this comment
:type recoverd_comment: str
:return: True if backend successfully registered.
:rtype: bool
"""
# check it
LOG.debug('Backend %s is already registered', backend)
LOG.debug('Checking its health')
try:
node = galera_cluster.find_node(backend.hostname, backend.port)
state = node.wsrep_local_state
LOG.debug('%s state: %d', node, state)
if state == GaleraNodeState.SYNCED:
LOG.debug('Node %s (%s) is healthy', node, backend.status)
if backend.status != BackendStatus.online:
LOG.debug('Deregistering %s (%s)', backend, backend.status)
proxysql.deregister_backend(backend)
backend.status = BackendStatus.online
if not recovered_hostgroup_id:
recovered_hostgroup_id = hostgroup_id
backend.hostgroup_id = recovered_hostgroup_id
if recoverd_comment:
backend.comment = recoverd_comment
LOG.debug('Registering %s (%s)', backend, backend.status)
proxysql.register_backend(backend)
else:
LOG.warn(
'Node %s is reachable but unhealty, '
'setting it OFFLINE_SOFT', node)
proxysql.set_status(backend, BackendStatus.offline_soft)
register_synced_backends(galera_cluster,
proxysql,
hostgroup_id,
comment=comment,
limit=limit,
ignore_backend=ignore_backend)
except GaleraClusterNodeNotFound:
LOG.warn('Backend %s is not a cluster member. Deregistering it.',
backend)
proxysql.deregister_backend(backend)
register_synced_backends(galera_cluster,
proxysql,
hostgroup_id,
comment=comment,
limit=limit,
ignore_backend=ignore_backend)
except OperationalError as err:
LOG.error(err)
LOG.error('Looks like backend %s is unhealthy. Deregistering it.',
backend)
proxysql.deregister_backend(backend)
register_synced_backends(galera_cluster,
proxysql,
hostgroup_id,
comment=comment,
limit=limit,
ignore_backend=ignore_backend)
return True