If you're getting the following on your patroni cluster:

Jun 24 23:30:50 psql02 etcd: failed to send out heartbeat on time (exceeded the 250ms timeout for 1.229927109s)
Jun 24 23:30:50 psql02 etcd: server is likely overloaded
Jun 24 23:30:50 psql02 etcd: failed to send out heartbeat on time (exceeded the 250ms timeout for 1.22987947s)
Jun 24 23:30:50 psql02 etcd: server is likely overloaded

ERROR:  cannot execute CREATE TABLE in a read-only transaction

Then you likely commented out these:

[root@psql03 ~]# cat /etc/haproxy/haproxy.cfg
global
    log         127.0.0.1 local0
    stats       socket /var/run/haproxy.sock mode 0600 level admin
    user        haproxy
    group       haproxy
    daemon
    debug
    maxconn 1024

defaults
    mode tcp
    log global
    option                  dontlognull
    option                  redispatch
    retries 2
    timeout client 30m
    timeout connect 4s
    timeout server 30m
    timeout check 5s

frontend psql-in
    mode tcp
    bind psql-c01:5432
    option tcplog
    default_backend             psql-back

backend psql-back
    mode        tcp
    option      tcplog
#    option     httpchk
#    http-check         expect status 200
    default-server inter 3s fall 3 rise 2 on-marked-down shutdown-se
    server      psql01.nix.mds.xyz    psql01.nix.mds.xyz:5432 maxconn 1024 check port 8008
    server      psql02.nix.mds.xyz    psql02.nix.mds.xyz:5432 maxconn 1024 check port 8008
    server      psql03.nix.mds.xyz    psql03.nix.mds.xyz:5432 maxconn 1024 check port 8008

listen stats
    bind :9000
    mode http
    stats enable
    stats hide-version
    stats realm Haproxy\ Statistics
    stats uri /haproxy-stats
    stats auth admin:nopassword
[root@psql03 ~]#

Uncomment the two lines above to resolve the issue.

Thx,
TK