Bucardo Syncing (Failed) - Yun2Infinity User Manual

Reason for failure¶

I have not digged very deep into why it does not work with the masadb. A very quick and brief diagnose with the experience is as follows:

The hypertable (OBSERVATION table) is not replicating.
For Master-Master replication:
- when posting to MasterDB1, the replication to MasterDB2 is very smooth.
- however, your next post to MasterDB2 will result in an error.
- I think this is because MasterDB2 locks itself when it is replicating MasterDB1 changes.
- when you post again to MasterDB2, the post will fail.
- this is not verified but just a guess.

Due to these reasons I have decided to give up on the use of Bucardo and pursue other ways of replicating the database.

This entry is based on these resources:

Go to the terminal on your Ubuntu machine. Run this command to download the masa3db package.
```
$ curl -L https://github.com/chenkianwee/bucardo_installation/archive/refs/tags/0.01.zip > bucardo-0.01.zip
```
a. If curl is not installed on your machine. Install it with this command.
```
$ sudo apt-get install curl
```
Unzip the file with this command.
```
$ unzip bucardo-0.01.zip
```
a. If unzip is not installed on your machine. Install it with this command.
```
$ sudo apt-get install unzip
```
For Masa3DB before release 0.05, you will have to add primary key to your observation table with this command in psql.
```
ALTER TABLE "OBSERVATIONS" ADD PRIMARY KEY ("ID", "PHENOMENON_TIME_START");
```

Install Bucardo go to:

cd bucardo-0.01/shellscript

Execute the install_bucardo.sh script with the following command.
```
sudo sh install_bucardo.sh
```
You will be asked to fill in these parameters. Since 5432 is already used by the FROST-Server we will change the port to 5431.
```
Enter DB Container Name
(default=bucardo):

Enter Port to listen to for the DB Container.
(default=5432): 5431
```

Once the installation is completed you will get this message.

Current connection settings:
1. Host:           <none>
2. Port:           5432
3. User:           postgres
4. Database:       bucardo
5. PID directory:  /var/run/bucardo
Creating superuser 'bucardo'
Installation is now complete.
Set "log_level" to "debug"

Go into the bucardo container with this command.
```
sudo docker exec -it bucardo bash
```
- Inside the container install ssh with the following command.
```
apt-get install ssh
```
Once installed establish a tunnel to the server where your FROST-Server database is hosted.
- For example I have a database hosted on chaosbox.com. In the command below I am mapping the port to my localhost address(127.0.0.1) and local port (5900).
```
ssh -L 127.0.0.1:5900:localhost:5432 -N -f -M -S ~/.ssh-tunnel.chaosbox.com user@chaosbox.com
```
  to check on the connection use this command
```
ssh -S ~/.ssh-tunnel.chaosbox.com -O check user@chaosbox.com
```
  to end the connection use this command
```
ssh -S ~/.ssh-tunnel.chaosbox.com -O exit user@chaosbox.com
```
- I have another database hosted on my local network.
```
ssh -L 127.0.0.1:5901:localhost:5432 -N -f -M -S ~/.ssh-tunnel.192.168.1.248 user@192.168.1.248
```

Add the two database to Bucardo. Fill in the parameters as according to your setup

bucardo add database $db1_name host=127.0.0.1 port=5900 dbname=spatempdb user=$user password=$password

bucardo add database $db2_name host=127.0.0.1 port=5901 dbname=spatempdb user=$user password=$password

check the database after you have added them

bucardo list dbs

Once the two databases are added you can create a sync with the command. In this command we are doing a master-master sync where both database have read and write capabilities. When there is a conflict, information on db1 will take priority.
```
bucardo add sync $sync_name dbs=db1:source,db2:source tables=all conflict='db1 db2'
```
If you want to do a master-standby sync specify as follow:
```
bucardo add sync $sync_name dbs=db1:source,db2:target tables=all conflict='db1 db2'
```
to check the sync added
```
bucardo list sync
```
Once the sync is added we need to start the sync by running this:
```
bucardo start
```
to stop the sync
```
bucardo stop
```
Once you start the sync you can check the status of the sync with this.
```
bucardo status $sync_name
```