1)Below is the status of the cluster when one of the nodes failed (node3:3306).

MySQL  node3:3306 ssl  JS > c.status()
{
    "clusterName": "myCluster", 
    "defaultReplicaSet": {
        "name": "default", 
        "primary": "node1:3306", 
        "ssl": "REQUIRED", 
        "status": "OK_NO_TOLERANCE", 
        "statusText": "Cluster is NOT tolerant to any failures. 1 member is not active", 
        "topology": {
            "node3:3306": {
                "address": "node3:3306", 
                "mode": "R/O", 
                "readReplicas": {}, 
                "role": "HA", 
                "status": "Missing"
            }, 
            "node2:3306": {
                "address": "node2:3306", 
                "mode": "R/O", 
                "readReplicas": {}, 
                "role": "HA", 
                "status": "ONLINE"
            }, 
            "node1:3306": {
                "address": "node1:3306", 
                "mode": "R/W", 
                "readReplicas": {}, 
                "role": "HA", 
                "status": "ONLINE"
            }
        }, 
        "topologyMode": "Single-Primary"
    }, 
    "groupInformationSourceMember": "node1:3306"
}

2) Take mysqldump from the master node (healthy node) using the following command.

[root@node1] db_backup]# mysqldump --all-databases --add-drop-database --single-transaction --triggers --routines --port=mysql_port --user=root -p > /db_backup/mysql_dump_03062019.sql
Enter password:
Warning: A partial dump from a server that has GTIDs will by default include the GTIDs of all transactions, even those that changed suppressed parts of the database. If you don't want to restore GTIDs, pass --set-gtid-purged=OFF. To make a complete dump, pass --all-databases --triggers --routines --events.

3) Execute below step to remove the failed node from the cluster.

MySQL  node1:3306 ssl  JS > c.rescan()
Rescanning the cluster...

Result of the rescanning operation for the 'default' ReplicaSet:
{
    "name": "default", 
    "newTopologyMode": null, 
    "newlyDiscoveredInstances": [], 
    "unavailableInstances": [
        {
            "host": "node3:3306", 
            "label": "node3:3306", 
            "member_id": "78ce3f2d-b970-11e9-87d9-06925c715652"
        }
    ]
}

The instance 'node3:3306' is no longer part of the ReplicaSet.
The instance is either offline or left the HA group. You can try to add it to the cluster again with the cluster.rejoinInstance('node3:3306') command or you can remove it from the cluster configuration.
Would you like to remove it from the cluster metadata? [Y/n]: y
Removing instance from the cluster metadata...
The instance 'node3:3306' was successfully removed from the cluster metadata.


 MySQL  node1:3306 ssl  JS > c.status()
{
    "clusterName": "myCluster", 
    "defaultReplicaSet": {
        "name": "default", 
        "primary": "node1:3306", 
        "ssl": "REQUIRED", 
        "status": "OK_NO_TOLERANCE", 
        "statusText": "Cluster is NOT tolerant to any failures.", 
        "topology": {
            "node2:3306": {
                "address": "node2:3306", 
                "mode": "R/O", 
                "readReplicas": {}, 
                "role": "HA", 
                "status": "ONLINE"
            }, 
            "node1:3306": {
                "address": "node1:3306", 
                "mode": "R/W", 
                "readReplicas": {}, 
                "role": "HA", 
                "status": "ONLINE"
            }
        }, 
        "topologyMode": "Single-Primary"
    }, 
    "groupInformationSourceMember": "node1:3306"
}

4) Stop group replication if it is still running on failed node.

mysql> STOP GROUP_REPLICATION;
Query OK, 0 rows affected (1.01 sec)

5) Reset “gtid_executed” on the failed node.

mysql> show global variables like 'GTID_EXECUTED';
+---------------+--------------------------------------------------------------------------------------------+
| Variable_name | Value                                                                                      |
+---------------+--------------------------------------------------------------------------------------------+
| gtid_executed | 01f27b9c-182a-11e9-a199-00505692188c:1-14134172,
e2aa897d-1828-11e9-85b3-00505692188c:1-12 |
+---------------+--------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

mysql> reset master;
Query OK, 0 rows affected (0.02 sec)

mysql> reset slave;
Query OK, 0 rows affected (0.02 sec)

mysql> show global variables like 'GTID_EXECUTED';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| gtid_executed |       |
+---------------+-------+
1 row in set (0.00 sec)

6) Disable “super_readonly_flag” on the failed node.

mysql> SELECT @@global.read_only, @@global.super_read_only;
+--------------------+--------------------------+
| @@global.read_only | @@global.super_read_only |
+--------------------+--------------------------+
|                  1 |                        1 |
+--------------------+--------------------------+
1 row in set (0.00 sec)

mysql> SET GLOBAL super_read_only = 0;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT @@global.read_only, @@global.super_read_only;
+--------------------+--------------------------+
| @@global.read_only | @@global.super_read_only |
+--------------------+--------------------------+
|                  1 |                        0 |
+--------------------+--------------------------+
1 row in set (0.00 sec)

7) Restore the mysqldump from master on to the failed node.

[root@node3] # mysql -uroot -p < mysql_dump_03062019.sql

8) Once restore is completed enable “super_readonly_flag” on the failed node.

mysql> SELECT @@global.read_only, @@global.super_read_only;
+--------------------+--------------------------+
| @@global.read_only | @@global.super_read_only |
+--------------------+--------------------------+
|                  1 |                        0 |
+--------------------+--------------------------+
1 row in set (0.00 sec)

mysql> SET GLOBAL super_read_only = 1;
Query OK, 0 rows affected (0.00 sec)


mysql> SELECT @@global.read_only, @@global.super_read_only;
+--------------------+--------------------------+
| @@global.read_only | @@global.super_read_only |
+--------------------+--------------------------+
|                  1 |                        1 |
+--------------------+--------------------------+
1 row in set (0.00 sec)

9) Finally add the failed node back to the innodb cluster.

 MySQL  node1:3306 ssl  JS > c.addInstance("cluster_user@node3")
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 ...

Validating instance at node3:3306...

This instance reports its own address as node3

Instance configuration is suitable.
WARNING: On instance 'node3:3306' membership change cannot be persisted since MySQL version 5.7.27 does not support the SET PERSIST command (MySQL version >= 8.0.11 required). Please use the .configureLocalInstance() command locally to persist the changes.
WARNING: On instance 'node1:3306' membership change cannot be persisted since MySQL version 5.7.27 does not support the SET PERSIST command (MySQL version >= 8.0.11 required). Please use the .configureLocalInstance() command locally to persist the changes.
WARNING: On instance 'node2:3306' membership change cannot be persisted since MySQL version 5.7.27 does not support the SET PERSIST command (MySQL version >= 8.0.11 required). Please use the .configureLocalInstance() command locally to persist the changes.
The instance 'cluster_user@node3' was successfully added to the cluster.


 MySQL  node1:3306 ssl  JS > c.status()
{
    "clusterName": "myCluster", 
    "defaultReplicaSet": {
        "name": "default", 
        "primary": "node1:3306", 
        "ssl": "REQUIRED", 
        "status": "OK", 
        "statusText": "Cluster is ONLINE and can tolerate up to ONE failure.", 
        "topology": {
            "node3:3306": {
                "address": "node3:3306", 
                "mode": "R/O", 
                "readReplicas": {}, 
                "role": "HA", 
                "status": "ONLINE"
            }, 
            "node2:3306": {
                "address": "node2:3306", 
                "mode": "R/O", 
                "readReplicas": {}, 
                "role": "HA", 
                "status": "ONLINE"
            }, 
            "node1:3306": {
                "address": "node1:3306", 
                "mode": "R/W", 
                "readReplicas": {}, 
                "role": "HA", 
                "status": "ONLINE"
            }
        }, 
        "topologyMode": "Single-Primary"
    }, 
    "groupInformationSourceMember": "node1:3306"
}

source https://stackoverflow.com/questions/55036255/a-node-in-mysql-5-7-innodb-cluster-is-crashed-and-unable-to-re-join-the-crashed special thanks to @sqlcheckpoint