pgsql 16.x Etcd Reports Version that breaks Patroni

[Marquis-of-Sandwiches]

Discussion with Patroni explains the issue and workaround of patroni/dcs/etcd3.py

patroni/patroni#3385

Summary:

curl --cacert /etc/pki/tls/certs/ca.crt --cert /etc/pki/tls/certs/host.crt --key /etc/pki/tls/private/host.key https://my-host-psqldb03.mydomain.com:2379/version -X GET -d '{}'

Curl returns {"etcdserver":"3.5.21","etcdcluster":"3.0.0"}

Patroni uses 3.0.0 to formulate the URL to get the cluster state. The URL returns 404 because etcd deprecated the API endpoint assuming it's a very old version of etcd API.

Curl needs to return something like {"etcdserver":"3.5.21","etcdcluster":"3.5.0"}

[jobinau]

IMO, this has nothing to do with Patroni. What you are attempting is to use is etcd version check on port 2379.
Please make sure the etcd version is used on every node.

[root@node0 /]# etcd --version
etcd Version: 3.5.12
Git SHA: e7b3bb6cc
Go Version: go1.20.13
Go OS/Arch: linux/amd64

In case you are using old API version, Please consider upgrading to API version 3
https://www.percona.com/blog/upgrading-to-the-new-etcd-version-from-3-3-for-patroni/