Upgrading Group Replication 6. Member expelled from group  - A suspicion has been raised on the member, and any timeout set by the group_replication_member_expel_timeout  system variable has expired, and the member has resumed communication with the group and found that it has been expelled. 7. Out of auto-rejoin attempts  - The  group_replication_autorejoin_tries  system variable was set to specify a number of auto-rejoin attempts after a loss of majority or expulsion, and the member completed this number of attempts without success. The following table summarizes the failure scenarios and actions in each case: Table 18.4 Exit actions in Group Replication failure situations Failure situation Group Replication started with START GROUP_REPLICATION Group Replication started with group_replication_start_on_boot =ON Member fails local configuration check Mismatch between joining member and group configuration super_read_only  and offline_mode  unchanged MySQL continues running Set  super_read_only=ON  at startup to prevent updates super_read_only  and offline_mode  unchanged MySQL continues running Set  super_read_only=ON at startup to prevent updates (Important) Applier error on member Distributed recovery not possible Group configuration change error Primary election error Unreachable majority timeout Member expelled from group Out of auto-rejoin attempts super_read_only  set to  ON OR offline_mode  and super_read_only  set to  ON OR MySQL shuts down super_read_only  set to  ON OR offline_mode  and super_read_only  set to  ON OR MySQL shuts down 18.8 Upgrading Group Replication This section explains how to upgrade a Group Replication setup. The basic process of upgrading members of a group is the same as upgrading stand-alone instances, see Section 2.11, “Upgrading MySQL”  for the actual process of doing upgrade and types available. Choosing between an in-place or logical upgrade depends on the amount of data stored in the group. Usually an in-place upgrade is faster, and therefore is recommended. You should also consult Section 17.5.3, “Upgrading a Replication Setup” . While you are in the process of upgrading an online group, in order to maximize availability, you might need to have members with different MySQL Server versions running at the same time. Group Replication includes compatibility policies that enable you to safely combine members running different versions of MySQL in the same group during the upgrade procedure. Depending on your group, the effects of these policies might affect the order in which you should upgrade group members. For details, see Section 18.8.1, “Combining Different Member Versions in a Group” . If your group can be taken fully offline see Section 18.8.2, “Group Replication Offline Upgrade” . If your group needs to remain online, as is common with production deployments, see Section 18.8.3, “Group Replication Online Upgrade”  for the different approaches available for upgrading a group with minimal downtime. 3786