How to execute mysql script insertion on terraform user_data? - mysql

Question

The last line of the script was not executed.
I tried to execute the code manually on the instance created and it was successful.
#!/bin/bash
#install tools
apt-get update -y
apt-get install mysql-client -y
#Create MySQL config file
echo "[mysql]" >> ~/.my.cnf
echo "user = poc5admin" >> ~/.my.cnf
echo "password = poc5password" >> ~/.my.cnf
#test
echo "endpoint = ${rds_endpoint}" >> ~/variables
hostip=$(hostname -I)
endpoint=${rds_endpoint}
echo "$hostip" >> ~/variables
#I have created a table here but I will remove the code since it is unnecessary...
#Create User
echo "CREATE USER 'poc5user'#'%' IDENTIFIED BY 'poc5pass';" >> ~/mysqlscript.sql
echo "GRANT EVENT ON * . * TO 'poc5user'#'%';" >> ~/mysqlscript.sql
cp mysqlscript.sql /home/ubuntu/mysqlscript.sql
mysql -h $endpoint -u poc5admin < ~/mysqlscript.sql
Expected result: There should be a Database, Table and User created on the RDS instance.

Answer 1

You can insert or create Database like this from the bash script but it is not recommended an approach to work with RDS. better to place your data over s3 and import from the s3.
Here is the example, that will create DB
resource "aws_db_instance" "db" {
allocated_storage = 20
storage_type = "gp2"
engine = "mysql"
engine_version = "5.7"
instance_class = "db.t2.micro"
name = "mydb"
username = "foo"
password = "foobarbaz"
parameter_group_name = "default.mysql5.7"
s3_import {
source_engine = "mysql"
source_engine_version = "5.6"
bucket_name = "mybucket"
bucket_prefix = "backups"
ingestion_role = "arn:aws:iam::1234567890:role/role-xtrabackup-rds-restore"
}
}
~/.my.cnf why you need this? better to place these script in the s3 file.
second thing, If you still interesting to run from your local environment then you can insert from local-exec
resource "null_resource" "main_db_update_table" {
provisioner "local-exec" {
on_failure = "fail"
interpreter = ["/bin/bash", "-c"]
command = <<EOT
mysql -h ${aws_rds_cluster.db.endpoint} -u your_username -pyour_password your_db < mysql_script.sql
EOT
}
}
But better to with s3.
If you want to import from remote, you can explore remote-exec.
With user-data, you can do this but it seems your MySQL script not generating properly. better to cp script to remote and then run with local exec in remote.

Answer 2

There is no such thing as terraform "user_data". User data is a bootstrap script for the EC2 instances which you can use to install software/binaries or to execute your script at the boot time.
The script will be executed by the cloud-init, not by the terraform itself. The responsibility of the terraform is to set user-data for the ec2 instances.
You may check the cloud-init output logs which should have the result of your user-data script also.
From your code, I am not able to understand which step you have copied the below file.
cp mysqlscript.sql /home/ubuntu/mysqlscript.sql
mysql -h $endpoint -u poc5admin < ~/mysqlscript.sql
I am assuming that you are creating a new server and it does not have any file.

Answer 3

Thank you for your inputs. I have found an answer by moving the config file to /etc/mysql/my.cnf and then executing
mysql -h $endpoint -u poc5admin < ~/mysqlscript.sql