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Make pod role label configurable (#2659)

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Close #2495
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Waynerv
2023-07-25 10:29:04 +02:00
committed by GitHub
parent 06db296612
commit 0e19e3e98e
7 changed files with 106 additions and 7 deletions
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docs/ENVIRONMENT.rst
+5 -1
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@@ -112,7 +112,11 @@ Kubernetes
- **PATRONI\_KUBERNETES\_NAMESPACE**: (optional) Kubernetes namespace where the Patroni pod is running. Default value is `default`.
- **PATRONI\_KUBERNETES\_LABELS**: Labels in format ``{label1: value1, label2: value2}``. These labels will be used to find existing objects (Pods and either Endpoints or ConfigMaps) associated with the current cluster. Also Patroni will set them on every object (Endpoint or ConfigMap) it creates.
- **PATRONI\_KUBERNETES\_SCOPE\_LABEL**: (optional) name of the label containing cluster name. Default value is `cluster-name`.
- **PATRONI\_KUBERNETES\_ROLE\_LABEL**: (optional) name of the label containing Postgres role (`master` or `replica`). Patroni will set this label on the pod it is running in. Default value is `role`.
- **PATRONI\_KUBERNETES\_ROLE\_LABEL**: (optional) name of the label containing role (master or replica or other custom value). Patroni will set this label on the pod it runs in. Default value is ``role``.
- **PATRONI\_KUBERNETES\_LEADER\_LABEL\_VALUE**: (optional) value of the pod label when Postgres role is `master`. Default value is `master`.
- **PATRONI\_KUBERNETES\_FOLLOWER\_LABEL\_VALUE**: (optional) value of the pod label when Postgres role is `replica`. Default value is `replica`.
- **PATRONI\_KUBERNETES\_STANDBY\_LEADER\_LABEL\_VALUE**: (optional) value of the pod label when Postgres role is ``standby-leader``. Default value is ``standby-leader``.
- **PATRONI\_KUBERNETES\_TMP\_ROLE\_LABEL**: (optional) name of the temporary label containing role (master or replica). Value of this label will always use the default of corresponding role. Set only when necessary.
- **PATRONI\_KUBERNETES\_USE\_ENDPOINTS**: (optional) if set to true, Patroni will use Endpoints instead of ConfigMaps to run leader elections and keep cluster state.
- **PATRONI\_KUBERNETES\_POD\_IP**: (optional) IP address of the pod Patroni is running in. This value is required when `PATRONI_KUBERNETES_USE_ENDPOINTS` is enabled and is used to populate the leader endpoint subsets when the pod's PostgreSQL is promoted.
- **PATRONI\_KUBERNETES\_PORTS**: (optional) if the Service object has the name for the port, the same name must appear in the Endpoint object, otherwise service won't work. For example, if your service is defined as ``{Kind: Service, spec: {ports: [{name: postgresql, port: 5432, targetPort: 5432}]}}``, then you have to set ``PATRONI_KUBERNETES_PORTS='[{"name": "postgresql", "port": 5432}]'`` and Patroni will use it for updating subsets of the leader Endpoint. This parameter is used only if `PATRONI_KUBERNETES_USE_ENDPOINTS` is set.
docs/kubernetes.rst
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@@ -32,6 +32,55 @@ Configuration
Patroni Kubernetes :ref:`settings <kubernetes_settings>` and :ref:`environment variables <kubernetes_environment>` are described in the general chapters of the documentation.
Customize role label
^^^^^^^^^^^^^^^^^^^^
By default, Patroni will set corresponding labels on the pod it runs in based on node's role, such as ``role=master``.
The key and value of label can be customized by `kubernetes.role_label`, `kubernetes.leader_label_value`, `kubernetes.follower_label_value` and `kubernetes.standby_leader_label_value`.
Note that if you migrate from default role labels to custom ones, you can reduce downtime by following migration steps:
1. Add a temporary label using original role value for the pod with `kubernetes.tmp_role_label` (like ``tmp_role``). Once pods are restarted they will get following labels set by Patroni:
.. code:: YAML
labels:
cluster-name: foo
role: master
tmp_role: master
2. After all pods have been updated, modify the service selector to select the temporary label.
.. code:: YAML
selector:
cluster-name: foo
tmp_role: master
3. Add your custom role label (e.g., set `kubernetes.leader_label_value=primary`). Once pods are restarted they will get following new labels set by Patroni:
.. code:: YAML
labels:
cluster-name: foo
role: primary
tmp_role: master
4. After all pods have been updated again, modify the service selector to use new role value.
.. code:: YAML
selector:
cluster-name: foo
role: primary
5. Finally, remove the temporary label from your configuration and update all pods.
.. code:: YAML
labels:
cluster-name: foo
role: primary
Examples
--------
docs/yaml_configuration.rst
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@@ -155,7 +155,11 @@ Kubernetes
- **namespace**: (optional) Kubernetes namespace where Patroni pod is running. Default value is `default`.
- **labels**: Labels in format ``{label1: value1, label2: value2}``. These labels will be used to find existing objects (Pods and either Endpoints or ConfigMaps) associated with the current cluster. Also Patroni will set them on every object (Endpoint or ConfigMap) it creates.
- **scope\_label**: (optional) name of the label containing cluster name. Default value is `cluster-name`.
- **role\_label**: (optional) name of the label containing role (master or replica). Patroni will set this label on the pod it runs in. Default value is ``role``.
- **role\_label**: (optional) name of the label containing role (master or replica or other custom value). Patroni will set this label on the pod it runs in. Default value is ``role``.
- **leader\_label\_value**: (optional) value of the pod label when Postgres role is ``master``. Default value is ``master``.
- **follower\_label\_value**: (optional) value of the pod label when Postgres role is ``replica``. Default value is ``replica``.
- **standby\_leader\_label\_value**: (optional) value of the pod label when Postgres role is ``standby-leader``. Default value is ``standby-leader``.
- **tmp_\role\_label**: (optional) name of the temporary label containing role (master or replica). Value of this label will always use the default of corresponding role. Set only when necessary.
- **use\_endpoints**: (optional) if set to true, Patroni will use Endpoints instead of ConfigMaps to run leader elections and keep cluster state.
- **pod\_ip**: (optional) IP address of the pod Patroni is running in. This value is required when `use_endpoints` is enabled and is used to populate the leader endpoint subsets when the pod's PostgreSQL is promoted.
- **ports**: (optional) if the Service object has the name for the port, the same name must appear in the Endpoint object, otherwise service won't work. For example, if your service is defined as ``{Kind: Service, spec: {ports: [{name: postgresql, port: 5432, targetPort: 5432}]}}``, then you have to set ``kubernetes.ports: [{"name": "postgresql", "port": 5432}]`` and Patroni will use it for updating subsets of the leader Endpoint. This parameter is used only if `kubernetes.use_endpoints` is set.
patroni/config.py
+2 -1
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@@ -475,7 +475,8 @@ class Config(object):
'REGISTER_SERVICE', 'SERVICE_CHECK_INTERVAL', 'SERVICE_CHECK_TLS_SERVER_NAME',
'SERVICE_TAGS', 'NAMESPACE', 'CONTEXT', 'USE_ENDPOINTS', 'SCOPE_LABEL', 'ROLE_LABEL',
'POD_IP', 'PORTS', 'LABELS', 'BYPASS_API_SERVICE', 'RETRIABLE_HTTP_CODES', 'KEY_PASSWORD',
'USE_SSL', 'SET_ACLS', 'GROUP', 'DATABASE') and name:
'USE_SSL', 'SET_ACLS', 'GROUP', 'DATABASE', 'LEADER_LABEL_VALUE', 'FOLLOWER_LABEL_VALUE',
'STANDBY_LEADER_LABEL_VALUE', 'TMP_ROLE_LABEL') and name:
value = os.environ.pop(param)
if name == 'CITUS':
if suffix == 'GROUP':
patroni/dcs/kubernetes.py
+19 -4
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@@ -752,6 +752,10 @@ class Kubernetes(AbstractDCS):
self._label_selector = ','.join('{0}={1}'.format(k, v) for k, v in self._labels.items())
self._namespace = config.get('namespace') or 'default'
self._role_label = config.get('role_label', 'role')
self._leader_label_value = config.get('leader_label_value', 'master')
self._follower_label_value = config.get('follower_label_value', 'replica')
self._standby_leader_label_value = config.get('standby_leader_label_value', 'standby-leader')
self._tmp_role_label = config.get('tmp_role_label')
self._ca_certs = os.environ.get('PATRONI_KUBERNETES_CACERT', config.get('cacert')) or SERVICE_CERT_FILENAME
super(Kubernetes, self).__init__({**config, 'namespace': ''})
if self._citus_group:
@@ -1263,19 +1267,30 @@ class Kubernetes(AbstractDCS):
def touch_member(self, data: Dict[str, Any]) -> bool:
cluster = self.cluster
if cluster and cluster.leader and cluster.leader.name == self._name:
role = 'master'
role = self._leader_label_value
tmp_role = 'master'
elif data['state'] == 'running' and data['role'] not in ('master', 'primary'):
role = data['role']
role = {
'replica': self._follower_label_value,
'standby-leader': self._standby_leader_label_value,
}.get(data['role'], data['role'])
tmp_role = data['role']
else:
role = None
tmp_role = None
role_labels = {self._role_label: role}
if self._tmp_role_label:
role_labels[self._tmp_role_label] = tmp_role
member = cluster and cluster.get_member(self._name, fallback_to_leader=False)
pod_labels = member and member.data.pop('pod_labels', None)
ret = member and pod_labels is not None\
and pod_labels.get(self._role_label) == role and deep_compare(data, member.data)
and all(pod_labels.get(k) == v for k, v in role_labels.items())\
and deep_compare(data, member.data)
if not ret:
metadata = {'namespace': self._namespace, 'name': self._name, 'labels': {self._role_label: role},
metadata = {'namespace': self._namespace, 'name': self._name, 'labels': role_labels,
'annotations': {'status': json.dumps(data, separators=(',', ':'))}}
body = k8s_client.V1Pod(metadata=k8s_client.V1ObjectMeta(**metadata))
ret = self._api.patch_namespaced_pod(self._name, self._namespace, body)
patroni/validator.py
+4
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@@ -995,6 +995,10 @@ schema = Schema({
Optional("namespace"): str,
Optional("scope_label"): str,
Optional("role_label"): str,
Optional("leader_label_value"): str,
Optional("follower_label_value"): str,
Optional("standby_leader_label_value"): str,
Optional("tmp_role_label"): str,
Optional("use_endpoints"): bool,
Optional("pod_ip"): Or(is_ipv4_address, is_ipv6_address),
Optional("ports"): [{"name": str, "port": int}],
tests/test_kubernetes.py
+22
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@@ -298,6 +298,28 @@ class TestKubernetesConfigMaps(BaseTestKubernetes):
self.k.touch_member({'state': 'running', 'role': 'replica'})
self.k.touch_member({'state': 'stopped', 'role': 'primary'})
self.k._role_label = 'isMaster'
self.k._leader_label_value = 'true'
self.k._follower_label_value = 'false'
self.k._standby_leader_label_value = 'false'
self.k._tmp_role_label = 'tmp_role'
self.k.touch_member({'state': 'running', 'role': 'replica'})
mock_patch_namespaced_pod.assert_called()
self.assertEqual(mock_patch_namespaced_pod.call_args.args[2].metadata.labels['isMaster'], 'false')
self.assertEqual(mock_patch_namespaced_pod.call_args.args[2].metadata.labels['tmp_role'], 'replica')
self.k.touch_member({'state': 'running', 'role': 'standby-leader'})
mock_patch_namespaced_pod.assert_called()
self.assertEqual(mock_patch_namespaced_pod.call_args.args[2].metadata.labels['isMaster'], 'false')
self.assertEqual(mock_patch_namespaced_pod.call_args.args[2].metadata.labels['tmp_role'], 'standby-leader')
self.k._name = 'p-0'
self.k.touch_member({'role': 'primary'})
mock_patch_namespaced_pod.assert_called()
self.assertEqual(mock_patch_namespaced_pod.call_args.args[2].metadata.labels['isMaster'], 'true')
self.assertEqual(mock_patch_namespaced_pod.call_args.args[2].metadata.labels['tmp_role'], 'master')
def test_initialize(self):
self.k.initialize()