Importing a MariaDB Docker Container to an existing cluster on Cluster Control

Hello,

Galera Replication works, building up the container works and when the container is up and running, SST successfully completes and the node is SYNCED to the cluster. SSH is set up, Passwordless SSH is set up from the Cluster Control node to this docker container.

When I'm importing it to a cluster (for monitoring and other automation like failover), Here's what happens : 

[15:34:19]:<em style='color: #da0bf3;'>galera-node-1</em>: Will retry in 10 secs (3/6).
[15:34:19]:<em style='color: #da0bf3;'>galera-node-1</em>: <strong style='color: red;'>Timeout connecting to galera-node-1.</strong>
[15:33:39]:<em style='color: #da0bf3;'>galera-node-1</em>: Will retry in 10 secs (2/6).
[15:33:39]:<em style='color: #da0bf3;'>galera-node-1</em>: <strong style='color: red;'>Timeout connecting to galera-node-1.</strong>
[15:32:59]:<em style='color: #da0bf3;'>galera-node-1</em>: Will retry in 10 secs (1/6).
[15:32:59]:<em style='color: #da0bf3;'>galera-node-1</em>: <strong style='color: red;'>Timeout connecting to galera-node-1.</strong>
[15:32:29]:<em style='color: #da0bf3;'>galera-node-1</em>: Checking ssh/sudo with credentials <strong style='color: #59a449;'>ssh_cred_job_6656</strong>.
[15:32:29]:Checking that nodes are not in another cluster.
[15:32:29]:Found in total 5 nodes.
[15:32:29]:Found node: '<em style='color: #c66211;'>galera-node-3</em>'
[15:32:29]:Found node: '<em style='color: #da0bf3;'>galera-node-4</em>'
[15:32:29]:Found node: '<em style='color: #7415f6;'>galera-node-5</em>'
[15:32:29]:Found node: '<em style='color: #877d0f;'>galera-node-2</em>'
[15:32:29]:Found node: '<em style='color: #da0bf3;'>galera-node-1</em>'
[15:32:29]:<em style='color: #c66211;'>galera-node-3</em>: Couldn't get wsrep_node_address status variable: ''
[15:32:29]:galera-node-3: ssh host down: beginExecuteAsScript failed: 'scp failure (Timeout connecting to galera-node-3.)'
[15:29:59]:<em style='color: #c66211;'>galera-node-3</em>: Checking wsrep_node_address.
[15:29:59]:<em style='color: #da0bf3;'>galera-node-4</em>: wsrep_node_address=galera-node-4
[15:29:49]:<em style='color: #da0bf3;'>galera-node-4</em>: Checking wsrep_node_address.
[15:29:49]:<em style='color: #7415f6;'>galera-node-5</em>: Couldn't get wsrep_node_address status variable: ''
[15:29:49]:galera-node-5: ssh host down: beginExecuteAsScript failed: 'scp failure (Timeout connecting to galera-node-3.)'
[15:27:19]:<em style='color: #7415f6;'>galera-node-5</em>: Checking wsrep_node_address.
[15:27:19]:<em style='color: #877d0f;'>galera-node-2</em>: Couldn't get wsrep_node_address status variable: ''
[15:27:19]:galera-node-2: ssh host down: beginExecuteAsScript failed: 'scp failure (Timeout connecting to galera-node-2.)'
[15:24:49]:<em style='color: #877d0f;'>galera-node-2</em>: Checking wsrep_node_address.
[15:24:49]:<em style='color: #da0bf3;'>galera-node-1</em>: Couldn't get wsrep_node_address status variable: ''
[15:24:49]:galera-node-1: ssh host down: beginExecuteAsScript failed: 'scp failure (Timeout connecting to galera-node-1.)'
[15:22:19]:<em style='color: #da0bf3;'>galera-node-1</em>: Checking wsrep_node_address.
[15:22:05]:<em style='color: #da0bf3;'>galera-node-4</em>:3307: Getting node list from the MySQL server.
[15:21:50]:<em style='color: #da0bf3;'>galera-node-4</em>:3307: Verifying the MySQL user/password.
[15:21:35]:<em style='color: #da0bf3;'>galera-node-4</em>: Checking ssh/sudo with credentials <strong style='color: #59a449;'>ssh_cred_job_6656</strong>.
[15:21:35]:Adding existing MySQL cluster.
[15:21:35]:Generating configuration for cluster <strong style='color: #59a449;'>Galera-cluster</strong>.
[15:21:33]:Adding cluster with type '<strong style='color: #59a449;'>galera</strong>', vendor '<strong style='color: #59a449;'>percona</strong>'.
[15:21:33]:CMON version <strong style='color: #59a449;'>1.9.5.6270</strong>.
Job spec:
{
  "command": "add_cluster",
  "job_data": {
    "cluster_name": "Galera-cluster",
    "cluster_type": "galera",
    "company_id": null,
    "config_template": "my57.cnf.galera",
    "datadir": "/var/lib/mysql",
    "db_password": "dLC5je9n6",
    "db_user": "root",
    "disable_firewall": true,
    "disable_selinux": true,
    "enable_cluster_autorecovery": false,
    "enable_information_schema_queries": false,
    "enable_node_autorecovery": false,
    "enable_nodes_autodetect": true,
    "galera_version": "3.x",
    "generate_token": true,
    "install_software": true,
    "monitored_mysql_port": "3307",
    "port": "****",
    "ssh_keyfile": "/root/.ssh/id_rsa",
    "ssh_port": "**",
    "ssh_user": "root",
    "sudo_password": "",
    "tag": "",
    "user_id": 5,
    "vendor": "percona",
    "version": "5.7",
    "nodes": [
      {
        "hostname": "galera-node-4",
        "port": "****"
      }
    ],
    "with_tags": []
  }
}

It is failing with timeouts, I don,t understand why, my firewall configs are all okay on all nodes, I can SSH from ClusterControl node to the node i want to add without password of course, and I do not understand why these errors happen (ssh host down: beginExecuteAsScript failed: 'scp failure (Timeout connecting to galera-node-3.) when the hosts are UP and online.

Is it possible in the first place to add a Galera Node that is a Docker Container ? (With SSH Configured within that container)