Bug #99251 Can't initialize function 'clone'; Plugin initialization function failed
Submitted: 14 Apr 2020 9:51 Modified: 28 May 2020 15:40
Reporter: Peter Hutchison Email Updates:
Status: Not a Bug Impact on me:
None 
Category:MySQL Server Severity:S2 (Serious)
Version:8.0.19 OS:Ubuntu (18.04.4 LTS)
Assigned to: MySQL Verification Team CPU Architecture:Any
Tags: Possible solution

[14 Apr 2020 9:51] Peter Hutchison
Description:
I am trying to add new instances to a SQL Innodb cluster and when I select the Clone option, it says:

Validating instance configuration at augusta:3306...

This instance reports its own address as augusta:3306

Instance configuration is suitable.
A new instance will be added to the InnoDB cluster. Depending on the amount of
data on the cluster this might take from a few seconds to several hours.

Adding instance to the cluster...

Cluster.addInstance: error installing plugin 'clone': augusta:3306: Can't initialize function 'clone'; Plugin initialization function failed. (RuntimeError)

If I try to manually load the plugin on the instance, it fails:
ERROR 1123 (HY000): Can't initialize function 'clone'; Plugin initialization function failed.

The plugin is installed on the first server in the cluster but it won't load on the others, the version of MySQL is the same on all ther servers:
mysqld --version
/usr/sbin/mysqld  Ver 8.0.19 for Linux on x86_64 (MySQL Community Server - GPL)
mysql  Ver 8.0.19 for Linux on x86_64 (MySQL Community Server - GPL)

I checked variables like the the ones mentioned in previous 8.0.17 bug report.

How to repeat:
1. Install mysql community 8.0.19 (server, client, mysqlsh, mysqlrouter) on 3 servers.
2. Setup users esp, root and cluadmin with full privileges on all 3 servers
3. Run mysqlsh on first server
4. Create innodb cluster e.g. mysqldevcluster
5. Add new instance e.g. 
var cl=dba.getCluster()
cl.addInstance('cluadmin@servername:3306')
[20 Apr 2020 10:28] Peter Hutchison
In my custom configuration in /etc/mysql/conf.d/hudd.cnf I had this line which if commented out would allow clone plugin to install:

explicit_defaults_for_timestamp=OFF
[28 May 2020 15:40] MySQL Verification Team
Hi,

explicit_defaults_for_timestamp is deprecated. This in my opinion is not a bug.

all best
Bogdan