[Imporve] The current use of K8s ConfigMap as lease judgement in Lorry may lead to availability defects.

[lingdie]

Consider the following scenarios:

1. In a single-master Kubernetes cluster: After the apiserver master node exits, Lorry's lease judgment becomes entirely unavailable.

2. In a three-master Kubernetes cluster: After the apiserver master node exits, testing reveals that Lorry's lease judgment might result in errors, causing the high-availability PostgreSQL cluster to re-elect a new primary.

code ref:

kubeblocks/pkg/lorry/dcs/k8s.go

Line 299 in 2d82e5a

func (store *KubernetesStore) CreateLease() error {

[xuriwuyun]

The PG switchover issue arises from Patroni when the API server is down, and Lorry do not demote the primary in case of a failed API server access. To address this problem, there are two possible approaches:

1. Implement high availability for the API server and perform upgrades one by one.
2. If the PG cluster has only one replica, disable the Patroni high availability functionality.