First, visit the websites of the dependencies and install as instructed. Then download the script galmin.py to any directory and create an alias pointing to it as follows:
alias galmin="python3 ~/{download_directory}/galmin.py"
then use the command galmin from now on to manage a Galera cluster.
When you first type galmin you will get the following help screen:
usage: galmin.py [-h] [--init] [--ping] [--install] [--start] [--stop]
[--bootstrap] [--status] [--server]
Galera Cluster Admin Tool
optional arguments:
-h, --help show this help message and exit
--init Creates a default config file named "cluster.config"
--ping Makes sure that all nodes are reachable by pinging them
--install Installs Galera cluster on the nodes specified in the config
file
--start Starts the cluster
--stop Stops the cluster
--bootstrap Marks the first cluster node as safe to bootstrap from
--status Shows cluster status report
--server Starts a local monitoring server on "http://localhost:8080"
Welcome to the Galera cluster admin command line tool. Before using this tool,
use the "--init" command to create a default config file named
"cluster.config" then edit it to specify your cluster nodes. Once a cluster
has been installed, run the "--bootstrap" command to mark the first cluster
node as safe to start the cluster from. After starting the cluster, use
the command "--server" to start a local monitoring server on
"http://localhost:8080" which can then be stopped using Ctrl-C.
To get started, first provision three Ubuntu 16.04 servers and assign static ips to them, also make sure that openssh-server
is installed on the three servers.
Now type:
galmin --init
and you will get the following:
creating file "./cluster.config"...
Done, the file has three nodes configured to default values.
Please make sure to edit this file and enter the correct
ips and ssh login credentials for the cluster nodes.
Add more nodes as desired using the following format:
label: [cluster node label]
ip: [cluster node static ip]
login: [login account user name used in ssh connections]
password: [password of the login account]
[an optional trailing empty line]
As instructed, edit the file "cluster.config" and enter the values as necessary.
After that make sure that the cluster servers are all up by typing:
galmin --ping
and if all is OK, you should see something like:
pinging "cluster_node_1" (192.168.0.91) ...
pinging "cluster_node_2" (192.168.0.92) ...
pinging "cluster_node_3" (192.168.0.93) ...
"cluster_node_1" (192.168.0.91) is up
"cluster_node_2" (192.168.0.92) is up
"cluster_node_3" (192.168.0.93) is up
you may want at this stage to ping each node from each other node.
Now we are ready to start the installation process.
Simply type:
galmin --install
and after a while the installation should be complete on all nodes. The installation installs mariadb server with galera at the same time. The default username for all databases on all nodes is root with a blank password.
Before starting the cluster, we need to mark the primary node (the first node in "cluster.config" by convention) as safe to start the cluster from. To do that, type:
galmin --bootstrap
Now we are ready to start the cluster, use:
galmin --start
to stop the cluster, use:
galmin --stop
after you start the cluster, (or just anytime) you can view the status of the cluster by issuing the command:
galmin --status
with an outpout similar to:
Node 1
------
label: ubuntu1
ip: 192.168.0.91
galera: installed
deamon: started
Node 2
------
label: ubuntu2
ip: 192.168.0.92
galera: installed
deamon: started
Node 3
------
label: ubuntu3
ip: 192.168.0.93
galera: installed
deamon: started
Cluster Size : 3
------------
Finally you can open another terminal window and start a local monitoring server by:
galmin --server
on the same machine open your browser and visit http://localhost:8080 to see something like:
