Although CloudFormation is very good in creating PostgreSQL database servers with Amazon RDS, the mundane task of creating logical database, schemas and users is not supported.
This custom PostgreSQL user provider automates the provisioning of PostgreSQL roles and databases.
It is quite easy: you specify a CloudFormation resource of the Custom::PostgreSQLUser, as follows:
KongUser:
Type: Custom::PostgreSQLUser
DependsOn: KongPassword
Properties:
User: kong
PasswordParameterName: /postgres/kong/PGPASSWORD
WithDatabase: true
DeletionPolicy: Retain
Database: # the server to create the new user or database in
Host: postgres
Port: 5432
DBName: root
User: root
PasswordParameterName: /postgres/root/PGPASSWORD # put your root password is in the parameter store
ServiceToken: !Sub 'arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:binxioio-cfn-postgresql-user-provider-vpc-${AppVPC}'
KongPassword:
Type: Custom::Secret
Properties:
Name: /postgres/kong/PGPASSWORD
KeyAlias: alias/aws/ssm
Alphabet: _&`'~-abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789
Length: 30
ServiceToken: !Sub 'arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:binxio-cfn-secret-provider'After the deployment, the Postgres user 'kong' has been created together with a matching database 'kong'. The password for the root database user has been obtained by querying the Parameter /postgres/root/PGPASSWORD. If you just want to create a user with which you can login to the PostgreSQL database server, without a database, specify WithDatabase as false.
The RetainPolicy by default is Retain. This means that the login to the database is disabled. If you specify drop, it will be dropped and your data will be lost.
To install this Custom Resource, type:
export VPC_ID=$(aws ec2 --output text --query 'Vpcs[?IsDefault].VpcId' describe-vpcs)
export SUBNET_ID=$(aws ec2 --output text --query Subnets[0].SubnetId \
describe-subnets --filters Name=vpc-id,Values=$VPC_ID)
export SG_ID=$(aws ec2 --output text --query "SecurityGroups[*].GroupId" \
describe-security-groups --group-names default --filters Name=vpc-id,Values=$VPC_ID)
aws cloudformation create-stack \
--capabilities CAPABILITY_IAM \
--stack-name cfn-postgresql-user-provider \
--template-body file://cloudformation/cfn-custom-resource-provider.json \
--parameters \
ParameterKey=VPC,ParameterValue=$VPC_ID \
ParameterKey=Subnet,ParameterValue=$SUBNET_ID \
ParameterKey=SecurityGroup,ParameterValue=$SG_ID
aws cloudformation wait stack-create-complete --stack-name cfn-postgresql-user-provider Note that this uses the default VPC, subnet and security group. As the Lambda functions needs to connect to the database. You will need to install this custom resource provider for each vpc that you want to be able to create database users.
This CloudFormation template will use our pre-packaged provider from s3://binxio-public/lambdas/cfn-postgresql-user-provider-0.5.1.zip.
If you have not done so, please install the secret provider too.
cd ..
git clone https https://github.com/binxio/cfn-secret-provider.git
cd cfn-secret-provider
aws cloudformation create-stack \
--capabilities CAPABILITY_IAM \
--stack-name cfn-secret-provider \
--template-body file://cloudformation/cfn-custom-resource-provider.json
aws cloudformation wait stack-create-complete --stack-name cfn-secret-provider
To install the simple sample of the Custom Resource, type:
aws cloudformation create-stack --stack-name cfn-database-user-provider-demo \
--template-body file://cloudformation/demo-stack.json
aws cloudformation wait stack-create-complete --stack-name cfn-database-user-provider-demoIt will create a postgres database too, so it is quite time consuming...
With this solution PostgreSQL users and databases can be provisioned just like a database, while keeping the passwords safely stored in the AWS Parameter Store.