patroni.dcs.kubernetes module¶

class patroni.dcs.kubernetes.CoreV1ApiProxy(use_endpoints: bool | None = False, bypass_api_service: bool | None = False)¶

Bases: object

Proxy class to work with k8s_client.CoreV1Api() object

_DEFAULT_RETRIABLE_HTTP_CODES = frozenset({500, 503, 504})¶

__init__(use_endpoints: bool | None = False, bypass_api_service: bool | None = False) → None¶

configure_retriable_http_codes(retriable_http_codes: List[int]) → None¶

configure_timeouts(loop_wait: int, retry_timeout: int | float, ttl: int) → None¶

refresh_api_servers_cache() → None¶

property use_endpoints: bool¶

class patroni.dcs.kubernetes.K8sClient¶

Bases: object

class ApiClient(bypass_api_service: bool | None = False)¶

Bases: object

_API_URL_PREFIX = '/api/v1/namespaces/'¶

__init__(bypass_api_service: bool | None = False) → None¶

_calculate_timeouts(api_servers: int, timeout: float | None = None) → Tuple[int, float, int]¶: Calculate a request timeout and number of retries per single K8s API server node. In case if the timeout per node is too small (less than one second) we will reduce the number of nodes. For the cluster with only one API server node we will try to do 1 retry. No retries for clusters with 2 or more API server nodes. We better rely on switching to a different node.

_do_http_request(retry: Retry | None, api_servers_cache: List[str], method: str, path: str, **kwargs: Any) → HTTPResponse¶

_get_api_servers(api_servers_cache: List[str]) → List[str]¶

static _handle_server_response(response: HTTPResponse, _preload_content: bool) → HTTPResponse | K8sObject¶

_load_api_servers_cache() → None¶

static _make_headers(headers: Dict[str, str] | None) → Dict[str, str]¶

_refresh_api_servers_cache(updating_cache: bool | None = False) → None¶

property api_servers_cache: List[str]¶

call_api(method: str, path: str, headers: Dict[str, str] | None = None, body: Any | None = None, _retry: Retry | None = None, _preload_content: bool = True, _request_timeout: float | None = None, **kwargs: Any) → HTTPResponse | K8sObject¶

refresh_api_servers_cache() → None¶

request(retry: Retry | None, method: str, path: str, timeout: int | float | Tuple[int | float, int | float] | Timeout | None = None, **kwargs: Any) → HTTPResponse¶

set_api_servers_cache_ttl(ttl: int) → None¶

set_base_uri(value: str) → None¶

set_read_timeout(timeout: int | float) → None¶

class CoreV1Api(api_client: ApiClient | None = None)¶

Bases: object

__init__(api_client: ApiClient | None = None) → None¶

class _K8sObjectTemplate(**kwargs: Any)¶

Bases: K8sObject

The template for objects which we create locally, e.g. k8s_client.V1ObjectMeta & co

__init__(**kwargs: Any) → None¶

__init__() → None¶

class rest¶

Bases: object

exception ApiException(status: int | None = None, reason: str | None = None, http_resp: HTTPResponse | None = None)¶

Bases: Exception

__init__(status: int | None = None, reason: str | None = None, http_resp: HTTPResponse | None = None) → None¶

class patroni.dcs.kubernetes.K8sConfig¶

Bases: object

exception ConfigException¶: Bases: Exception

__init__() → None¶

static _get_by_name(config: Dict[str, List[Dict[str, Any]]], section: str, name: str) → Dict[str, Any] | None¶

_make_headers(token: str | None = None, **kwargs: Any) → None¶

_pool_config_from_file_or_data(config: Dict[str, str], file_key_name: str, pool_key_name: str) → None¶

_read_token_file() → str¶

_set_token(token: str) → None¶

property headers: Dict[str, str]¶

load_incluster_config(ca_certs: str = '/var/run/secrets/kubernetes.io/serviceaccount/ca.crt', token_refresh_interval: timedelta = datetime.timedelta(seconds=60)) → None¶

load_kube_config(context: str | None = None) → None¶

property server: str¶

exception patroni.dcs.kubernetes.K8sConnectionFailed¶: Bases: K8sException

exception patroni.dcs.kubernetes.K8sException¶: Bases: Exception

class patroni.dcs.kubernetes.K8sObject(kwargs: Dict[str, Any])¶

Bases: object

__init__(kwargs: Dict[str, Any]) → None¶

classmethod _wrap(parent: str | None, value: Any) → Any¶

get(name: str, default: Any | None = None) → Any | None¶

to_dict() → Dict[str, Any]¶

class patroni.dcs.kubernetes.Kubernetes(config: Dict[str, Any])¶

Bases: AbstractDCS

_CITUS_LABEL = 'citus-group'¶

__init__(config: Dict[str, Any]) → None¶

Prepare DCS paths, Citus group ID, initial values for state information and processing dependencies.

Variables:: config – dict, reference to config section of selected DCS. i.e.: zookeeper for zookeeper, etcd for etcd, etc…

__load_cluster(group: str | None, loader: Callable[[Dict[str, Any]], Cluster | Dict[int, Cluster]]) → Cluster | Dict[int, Cluster]¶

__target_ref(leader_ip: str, latest_subsets: List[K8sObject], pod: K8sObject) → K8sObject¶

_abc_impl = <_abc._abc_data object>¶

_citus_cluster_loader(path: Dict[str, Any]) → Dict[int, Cluster]¶

Load and build all Patroni clusters from a single Citus cluster.

Parameters:: path – the path in DCS where to load Cluster(s) from.
Returns:: all Citus groups as dict, with group IDs as keys and Cluster objects as values or a Cluster object representing the coordinator with filled Cluster.workers attribute.

_cluster_from_nodes(group: str, nodes: Dict[str, K8sObject], pods: Collection[K8sObject]) → Cluster¶

_cluster_loader(path: Dict[str, Any]) → Cluster¶

Load and build the Cluster object from DCS, which represents a single Patroni or Citus cluster.

Parameters:: path – the path in DCS where to load Cluster(s) from.
Returns:: Cluster instance.

property _config_resource_version: str | None¶

_create_config_service() → None¶

_delete_leader(leader: Leader) → bool¶: Unused

_load_cluster(path: str, loader: Callable[[Any], Cluster | Dict[int, Cluster]]) → Cluster | Dict[int, Cluster]¶

Main abstract method that implements the loading of Cluster instance.

Note

Internally this method should call the loader method that will build Cluster object which represents current state and topology of the cluster in DCS. This method supposed to be called only by the get_cluster() method.

Parameters:

path – the path in DCS where to load Cluster(s) from.
loader – one of _cluster_loader() or _citus_cluster_loader().

Raise:

DCSError in case of communication problems with DCS. If the current node was running as a primary and exception raised, instance would be demoted.

_map_subsets(endpoints: Dict[str, Any], ips: List[str]) → None¶

_patch_or_create(name: str, annotations: Dict[str, Any], resource_version: str | None = None, patch: bool = False, retry: Callable[[...], Any] | None = None, ips: List[str] | None = None) → K8sObject¶

Patch or create K8s object, Endpoint or ConfigMap.

Parameters:

name – the name of the object.
annotations – mapping of annotations that we want to create/update.
resource_version – object should be updated only if the resource_version matches provided value.
patch – True if we know in advance that the object already exists and we should patch it.
retry – a callable that will take care of retries
ips –
IP address that we want to put to the subsets of the endpoint. Could have following values:
- None - when we don’t need to touch subset;
- [] - to set subsets to the empty list, when delete_leader() method is called;
- ['ip.add.re.ss'] - when we want to make sure that the subsets of the leader endpoint contains the IP address of the leader, that we get from the kubernetes.pod_ip;
- [''] - when we want to make sure that the subsets of the leader endpoint contains the IP address of the leader, but kubernetes.pod_ip configuration is missing. In this case we will try to take the IP address of the Pod which name matches name from the config file.

Returns:

the new V1Endpoints or V1ConfigMap object, that was created or updated.

_update_leader(leader: Leader) → bool¶: Unused

_update_leader_with_retry(annotations: Dict[str, Any], resource_version: str | None, ips: List[str]) → bool¶

_wait_caches(stop_time: float) → None¶

_write_failsafe(value: str) → bool¶: Unused

_write_leader_optime(last_lsn: str) → bool¶: Unused

_write_status(value: str) → bool¶: Unused

attempt_to_acquire_leader() → bool¶

Attempt to acquire leader lock.

Note

This method should create /leader key with the value _name.

The key must be created atomically. In case the key already exists it should not be overwritten and False must be returned.

If key creation fails due to DCS not being accessible or because it is not able to process requests (hopefully temporary), the DCSError exception should be raised.

Returns:: True if key has been created successfully.

cancel_initialization() → bool¶

Removes the initialize key for a cluster.

Returns:: True if successfully committed to DCS.

client_path(path: str) → str¶

Construct the absolute key name from appropriate parts for the DCS type.

Parameters:: path – The key name within the current Patroni cluster.
Returns:: absolute key name for the current Patroni cluster.

static compare_ports(p1: K8sObject, p2: K8sObject) → bool¶

delete_cluster(*args: Any, **kwargs: Any) → Any¶

Delete cluster from DCS.

Returns:: True if successfully committed to DCS.

delete_leader(leader: Leader | None, last_lsn: int | None = None) → bool¶

Update optime/leader and voluntarily remove leader key from DCS.

This method should remove leader key if current instance is the leader.

Parameters:

leader – Leader object with information about the leader.
last_lsn – latest checkpoint location in bytes.

Returns:

boolean result of called abstract _delete_leader().

delete_sync_state(version: str | None = None) → bool¶

Patch annotations of $SCOPE-sync Endpoint or ConfigMap with empty values.

Effectively it removes “leader” and “sync_standby” annotations from the object. :param version: last known resource_version for conditional update of the object :returns: True if “delete” was successful

get_citus_coordinator() → Cluster | None¶

Load the Patroni cluster for the Citus Coordinator.

Note

This method is only executed on the worker nodes (group!=0) to find the coordinator.

Returns:: Select Cluster instance associated with the Citus Coordinator group ID.

initialize(create_new: bool = True, sysid: str = '') → bool¶

Race for cluster initialization.

This method should atomically create initialize key and return True, otherwise it should return False.

Parameters:

create_new – False if the key should already exist (in the case we are setting the system_id).
sysid – PostgreSQL cluster system identifier, if specified, is written to the key.

Returns:

True if key has been created successfully.

property leader_path: str¶: Get the client path for leader.

manual_failover(leader: str | None, candidate: str | None, scheduled_at: datetime | None = None, version: str | None = None) → bool¶

Prepare dictionary with given values and set /failover key in DCS.

Parameters:

leader – value to set for leader.
candidate – value to set for member.
scheduled_at – value converted to ISO date format for scheduled_at.
version – for conditional update of the key/object.

Returns:

True if successfully committed to DCS.

static member(pod: K8sObject) → Member¶

patch_or_create(*args: Any, **kwargs: Any) → Any¶

patch_or_create_config(annotations: Dict[str, Any], resource_version: str | None = None, patch: bool = False, retry: bool = True) → bool¶

reload_config(config: Config | Dict[str, Any]) → None¶

Handles dynamic config changes.

Either cause by changes in the local configuration file + SIGHUP or by changes of dynamic configuration

retry(method: Callable[[...], Any], *args: Any, **kwargs: Any) → Any¶

set_config_value(value: str, version: str | None = None) → bool¶

Create or update /config key in DCS.

Parameters:

value – new value to set in the config key.
version – for conditional update of the key/object.

Returns:

True if successfully committed to DCS.

set_failover_value(value: str, version: str | None = None) → bool¶: Unused

set_history_value(value: str) → bool¶

Set value for history in DCS.

Parameters:: value – new value of history key/object.
Returns:: True if successfully committed to DCS.

set_retry_timeout(retry_timeout: int) → None¶: Set the new value for retry_timeout.

set_sync_state_value(value: str, version: str | None = None) → bool¶: Unused

set_ttl(ttl: int) → bool | None¶: Set the new ttl value for DCS keys.

static subsets_changed(last_observed_subsets: List[K8sObject], ip: str, ports: List[K8sObject]) → bool¶

>>> ip = '1.2.3.4'
>>> a = [k8s_client.V1EndpointAddress(ip=ip)]
>>> s = [k8s_client.V1EndpointSubset(addresses=a)]
>>> Kubernetes.subsets_changed(s, '1.2.3.5', [])
True
>>> s = [k8s_client.V1EndpointSubset(addresses=a, ports=[k8s_client.V1EndpointPort(protocol='TCP', port=1)])]
>>> Kubernetes.subsets_changed(s, '1.2.3.4', [k8s_client.V1EndpointPort(port=5432)])
True
>>> p1 = k8s_client.V1EndpointPort(name='port1', port=1)
>>> p2 = k8s_client.V1EndpointPort(name='port2', port=2)
>>> p3 = k8s_client.V1EndpointPort(name='port3', port=3)
>>> s = [k8s_client.V1EndpointSubset(addresses=a, ports=[p1, p2])]
>>> Kubernetes.subsets_changed(s, ip, [p2, p3])
True
>>> s2 = [k8s_client.V1EndpointSubset(addresses=a, ports=[p2, p1])]
>>> Kubernetes.subsets_changed(s, ip, [p2, p1])
False

take_leader() → bool¶

Establish a new leader in DCS.

Note

This method should create leader key with value of _name and ttl of ttl.

Since it could be called only on initial cluster bootstrap it could create this key regardless, overwriting the key if necessary.

Returns:: True if successfully committed to DCS.

touch_member(*args: Any, **kwargs: Any) → Any¶

Update member key in DCS.

Note

This method should create or update key with the name with /members/ + _name and the value of data in a given DCS.

Parameters:: data – information about an instance (including connection strings).
Returns:: True if successfully committed to DCS.

property ttl: int¶: Get current ttl value.

update_leader(leader: Leader, last_lsn: int | None, slots: Dict[str, int] | None = None, failsafe: Dict[str, str] | None = None) → bool¶

Update leader key (or session) ttl and optime/leader.

Parameters:

leader – Leader object with information about the leader.
last_lsn – absolute WAL LSN in bytes.
slots – dictionary with permanent slots confirmed_flush_lsn.
failsafe – if defined dictionary passed to write_failsafe().

Returns:

True if leader key (or session) has been updated successfully.

watch(leader_version: str | None, timeout: float) → bool¶

Sleep if the current node is a leader, otherwise, watch for changes of leader key with a given timeout.

Parameters:

leader_version – version of a leader key.
timeout – timeout in seconds.

Returns:

if True this will reschedule the next run of the HA cycle.

write_leader_optime(last_lsn: int) → None¶

Write value for WAL LSN to optime annotation of the leader object.

Parameters:: last_lsn – absolute WAL LSN in bytes.

write_sync_state(leader: str | None, sync_standby: Collection[str] | None, version: str | None = None) → SyncState | None¶

Prepare and write annotations to $SCOPE-sync Endpoint or ConfigMap.

Parameters:

leader – name of the leader node that manages /sync key
sync_standby – collection of currently known synchronous standby node names
version – last known resource_version for conditional update of the object

Returns:

the new SyncState object or None

exception patroni.dcs.kubernetes.KubernetesError(value: Any)¶: Bases: DCSError

exception patroni.dcs.kubernetes.KubernetesRetriableException(orig: ApiException)¶

Bases: ApiException

__init__(orig: ApiException) → None¶

property sleeptime: int | None¶

class patroni.dcs.kubernetes.ObjectCache(dcs: Kubernetes, func: Callable[[...], Any], retry: Retry, condition: Condition, name: str | None = None)¶

Bases: Thread

__init__(dcs: Kubernetes, func: Callable[[...], Any], retry: Retry, condition: Condition, name: str | None = None) → None¶

This constructor should always be called with keyword arguments. Arguments are:

group should be None; reserved for future extension when a ThreadGroup class is implemented.

target is the callable object to be invoked by the run() method. Defaults to None, meaning nothing is called.

name is the thread name. By default, a unique name is constructed of the form “Thread-N” where N is a small decimal number.

args is a list or tuple of arguments for the target invocation. Defaults to ().

kwargs is a dictionary of keyword arguments for the target invocation. Defaults to {}.

If a subclass overrides the constructor, it must make sure to invoke the base class constructor (Thread.__init__()) before doing anything else to the thread.

_build_cache() → None¶

_do_watch(resource_version: str) → None¶

static _finish_response(response: HTTPResponse) → None¶

_list() → K8sObject¶

_process_event(event: Dict[str, Any | Dict[str, Dict[str, Any] | Any]]) → None¶

_watch(resource_version: str) → HTTPResponse¶

copy() → Dict[str, K8sObject]¶

delete(name: str, resource_version: str) → Tuple[bool, K8sObject | None]¶

get(name: str) → K8sObject | None¶

is_ready() → bool¶: Must be called only when holding the lock on _condition

kill_stream() → None¶

run() → None¶

Method representing the thread’s activity.

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.

set(name: str, value: K8sObject) → Tuple[bool, K8sObject | None]¶

patroni.dcs.kubernetes._cleanup_temp_files() → None¶

patroni.dcs.kubernetes._create_temp_file(content: bytes) → str¶

patroni.dcs.kubernetes._run_and_handle_exceptions(method: Callable[[...], Any], *args: Any, **kwargs: Any) → Any¶

patroni.dcs.kubernetes.catch_kubernetes_errors(func: Callable[[...], Any]) → Callable[[...], Any]¶

patroni.dcs.kubernetes.to_camel_case(value: str) → str¶