Setup: Multi node¶

BlueChi is intended for multi-node environments with a predefined number of nodes. This section describes how to set it up based on an example with two machines - a laptop and a raspberry pi. The diagram below depicts the desired state of the system:

BlueChi multi node setup diagram

Installation and configuration¶

The main node will be the laptop. So first of all, let’s install the controller, the agent and the CLI tool as well as the SELinux policy on it:

dnf install bluechi bluechi-agent bluechi-ctl bluechi-selinux

The raspberry pi will be (one of) the managed node in this example. Therefore, only install the agent and the SELinux policy on it:

dnf install bluechi-agent bluechi-selinux

Once the installations succeeded, BlueChi needs to be configured on both machines.

Configuring the main node¶

Let’s start with the main node (the laptop in this case). The configuration of the controller running on the laptop is similar to the single node setup with two exceptions:

pi needs to be added as another node
pi is a remote agent and will connect to BlueChi via TCP/IP. By default, the privileged port 842 is used. To avoid any firewall issues for this demo, let’s overwrite this setting and use the port 2020.

echo -e "[bluechi-controller]\nControllerPort=2020\nAllowedNodeNames=$(hostname),pi\n" > /etc/bluechi/controller.conf.d/1.conf

Let’s also create the configuration for the local agent on the laptop to use the Unix Domain Socket:

echo -e "[bluechi-agent]\nControllerAddress=unix:path=/run/bluechi/bluechi.sock\n" > /etc/bluechi/agent.conf.d/1.conf

Configuring the managed node¶

In the next step the managed node (the raspberry pi in this case) needs to be configured. The managed node needs to know where to connect to, so the settings for the ControllerHost as well as the ControllerPort have to be set to the IP and Port of the main node. In addition, the NodeName has to be set to pi (as set in the AllowedNodeNames in the previous section).

Assuming the main nodes IP within the network is 192.168.42.10, the configuration file for the agent on the raspberry pi can be created like this:

echo -e "[bluechi-agent]\nControllerHost=192.168.42.10\nControllerPort=2020\n" > /etc/bluechi/agent.conf.d/1.conf

The content of the new file should be:

$ cat /etc/bluechi/agent.conf.d/1.conf

[bluechi-controller]
ControllerHost=192.168.42.10
ControllerPort=2020

Running BlueChi¶

After installation and configuration has been completed, let’s start the systemd services.

Starting the controller and agent on the main node (laptop):

systemctl start bluechi-controller bluechi-agent

Switching to the managed node (raspberry pi), start the agent:

systemctl start bluechi-agent

Once the services are up and running, the journald logs on the laptop should show that the both agents have successfully connected to the controller:

$ journalctl -u bluechi-controller
Dec 18 08:03:03 localhost systemd[1]: Started BlueChi Controller systemd service
Dec 18 08:03:03 localhost bluechi-controller[680]: Starting bluechi-controller 0.10.0-0
Dec 17 16:13:43 localhost bluechi-controller[2539]: Waiting for connection requests on port 842...
Dec 17 16:13:43 localhost bluechi-controller[2539]: Waiting for connection requests on socket /run/bluechi/bluechi.sock...
Dec 18 08:03:03 localhost bluechi-controller[680]: Heartbeat disabled since configured interval '0' is <=0
Dec 18 08:03:03 localhost bluechi-controller[680]: Registered managed node from fd 9 as 'local'
Dec 18 08:03:03 localhost bluechi-controller[680]: Registered managed node from fd 10 as 'pi'
...

Let’s use bluechictl on the main node to list all units:

# list all units on the laptop
$ bluechictl list-units laptop

NODE                |ID                                                         |   ACTIVE|     SUB
====================================================================================================
laptop              |time-sync.target                                           | inactive|     dead
laptop              |nfs-idmapd.service                                         | inactive|     dead
laptop              |sys-devices-platform-serial8250-tty-ttyS5.device           |   active|  plugged
laptop              |dev-disk-by\x2did-wwn\x2d0x5001b448b9db9490\x2dpart3.device|   active|  plugged
laptop              |podman.socket                                              |   active|listening
...

# list all units on the raspberry pi
$ bluechictl list-units pi

NODE                |ID                                                         |   ACTIVE|     SUB
====================================================================================================
pi                  |acpid.path                                                 |   active|  running
pi                  |system-systemd\x2dcryptsetup.slice                         |   active|   active
pi                  |nfs-kernel-server.service                                  | inactive|     dead
pi                  |dev-ttyS24.device                                          |   active|  plugged
pi                  |dbus.service                                               |   active|  running
...

The setup works!

For more examples on how to use BlueChi, please see refer to the examples section.

Note

For a full list of available commands of bluechictl, please refer to bluechictl(1).