question about loose-group_replication_start_on_boot when all members reboot simultaneously

[Fabian Santiago]

hello. i did some searching and couldn't find mention of this. apologies if there is somewhere else...

all of this has taken place on 2 servers with matching system specs:
Ubuntu 24.04.2 LTS
kernel: 6.8.0-58-generic
mysql Ver 8.0.41-0ubuntu0.24.04.1 for Linux on x86_64 ((Ubuntu))

i setup a multi-primary replication group with 2 members. basic, mostly default boiler plate config options used:

[mysqld]
## binlog_format = MIXED

# General replication settings
disabled_storage_engines="MyISAM,BLACKHOLE,FEDERATED,ARCHIVE,MEMORY"
gtid_mode = ON
enforce_gtid_consistency = ON
master_info_repository = TABLE
relay_log_info_repository = TABLE
binlog_checksum = NONE
log_slave_updates = ON
log_bin = binlog
binlog_format = ROW
transaction_write_set_extraction = XXHASH64
loose-group_replication_bootstrap_group = OFF
loose-group_replication_start_on_boot = ON
loose-group_replication_ssl_mode = REQUIRED
loose-group_replication_recovery_use_ssl = 1

# Shared replication group configuration
loose-group_replication_group_name = "xxx"
loose-group_replication_ip_whitelist = "xxx"
loose-group_replication_group_seeds = "xxx"

# Single or Multi-primary mode? Uncomment these two lines
# for multi-primary mode, where any host can accept writes
loose-group_replication_single_primary_mode = OFF
loose-group_replication_enforce_update_everywhere_checks = ON

# Host specific replication configuration
server_id = x
bind-address = "xxx"
report_host = "xxx"
loose-group_replication_local_address = "xxx"

the config parameters i'm concerned with is "loose-group_replication_start_on_boot = ON".

if both servers reboot in too close proximity, and thus boot without another master being online, they come up with replication stopped. i believe this is to be expected. when rebooted one at a time, and with enough time in between each reboot that the whole repl group doesn't go down at once, it seems to come back up ok.

is there any way anyone has accomplished getting the repl group to start on its own in this scenario without logging into the cli and issuing the commands to re-bootstrap, start it? i'm curious. thanks.