server_id force to be "1" in all nodes

I created PXC 3 nodes environment by official Docker image of Percona XtraDB Cluster 5.7.

I add “server_id” parameter in my.cnf of each node, as below :

node1 : server_id = 10
node2 : server_id = 20
node3 : server_id = 30

However, after starting all nodes, it seems “server_id = 1”.

mysql -u root -ppassword -h 127.0.0.1 -P 13306 -e “show global variables like ‘server_id’”

mysql: [Warning] Using a password on the command line interface can be insecure.
±--------------±------+
| Variable_name | Value |
±--------------±------+
| server_id | 1 |
±--------------±------+

https://www.percona.com/blog/2015/07/16/bypassing-sst-pxc-binary-logs/

According to above blog post, the same server-id is recommended.
This behavior is the specification or not ?

This is bit strange. I tried the same at my end with some random server_id but I see the assigned server_id.

./bin/mysql --user root -S -e “select @@server_id
±------------+
| @@server_id |
±------------+
| 433 |
±------------+

±----------------+
| @@version |
±----------------+
| 5.7.17-13-29.20 |
±----------------+

Hi krunalbauskar,

Sorry for my late. I’m appreciate your test.
It seems to be problem in only my environment.

So I’ll survey more, thanks.