【Amazon RDS】Restoring From a DB Snapshot with AWS CLI

In this post, I will illustrate how to restore a DB instance from a DB Snapshot with AWS CLI (Version "1.11.145").

Overview

• We would like to restore a DB instance to the same state as a backed up DB instance
• After checking the new DB instance, delete the current DB instance

How to restore from a DB Snapshot

Step1. Configure environment variables

export AWS_ACCESS_KEY_ID=******
export AWS_SECRET_ACCESS_KEY=******
export AWS_DEFAULT_REGION=us-west-2

Step2. Checking AWS account and IAM users

It is a good practice to check the IAM user and AWS account ID first.

aws sts get-caller-identity

Step3. Get information on the DB Instance to be restored

db_instance=mydbinstance
echo ${db_instance}

aws rds describe-db-instances --db-instance-identifier ${db_instance} > ${db_instance}.json

Step4. Execute restore

Configure variables according to the DB instance we want to restore.

db_new_instance=mynewdbinstance
instance_class=db.t2.micro
subnet_group=mySubnetgroup
snapshot=mySnapshotid

echo ${db_new_instance}
echo ${instance_class}
echo ${subnet_group}
echo ${snapshot}

Select options according to the DB instance to be restored. AWS CLI Command Reference | restore-db-instance-from-db-snapshot

aws rds restore-db-instance-from-db-snapshot \
--db-instance-identifier ${db_new_instance} \
--db-snapshot-identifier ${snapshot} \
--db-instance-class ${instance_class} \
--db-subnet-group-name ${subnet_group} \
--no-publicly-accessible \
--multi-az

Step5. Wait until the restored DB instance becomes available

AWS CLI Command Reference | db-instance-available

aws rds wait db-instance-available --db-instance-identifier ${db_new_instance}

Step6. Modifying Parameter Group and Security Group

The parameter group and security groups associated with the restored instance are assigned to their defaults. Therefore, we should modify the parameter group and security groups.

paramter_group=mydbparametergroup
security_group=vpcsecuritygroup

echo ${paramter_group}
echo ${security_group}

AWS CLI Command Reference | modify-db-instance

aws rds modify-db-instance \
--db-instance-identifier ${db_new_instance} \
--db-parameter-group-name ${paramter_group} \
--vpc-security-group-ids ${security_group} \
--apply-immediately

Step7. Rebooting a DB Instance to apply changes

AWS CLI Command Reference | reboot-db-instance

aws rds reboot-db-instance \
--db-instance-identifier ${db_new_instance}

Step8. Wait until the restored DB Instance becomes available

aws rds wait db-instance-available --db-instance-identifier ${db_new_instance}

Step9. Get information on the restored DB Instance

aws rds describe-db-instances --db-instance-identifier ${db_new_instance} > ${db_new_instance}.json

Step10. Check the difference between the current DB Instance and the restored DB Instance

• DBInstanceIdentifier
• Address InstanceCreateTime
• LatestRestorableTime
• DbiResourceId
• DBInstanceArn

If values other than the above are the same, the restore process is completed.

diff ${db_instance}.json ${db_new_instance}.json

An example

$ diff ${db_instance}.json ${db_new_instance}.json
4c4
< "DBInstanceIdentifier": "mydbinstance", --- > "DBInstanceIdentifier": "mynewdbinstance",
11c11
< "Address": "mydbinstance.abcde*******.us-west-2.rds.amazonaws.com", --- > "Address": "mynewdbinstance.abcde*******.us-west-2.rds.amazonaws.com",
16c16
< "InstanceCreateTime": "2017-09-03T06:05:09.731Z", --- > "InstanceCreateTime": "2017-09-03T06:48:12.348Z",
64c64
< "LatestRestorableTime": "2017-09-03T06:35:00Z", --- > "LatestRestorableTime": "2017-09-03T07:00:00Z",
81c81
< "DbiResourceId": "db-RVYFY6********************", --- > "DbiResourceId": "db-5BKZOM********************",
86c86
< "DBInstanceArn": "arn:aws:rds:us-west-2:123456789012:db:mydbinstance", --- > "DBInstanceArn": "arn:aws:rds:us-west-2:123456789012:db:mynewdbinstance",

If the restore operation changes the new DB instance to a different availability zone, we can change it to the original availability zone using the --force-failover parameter.

aws rds reboot-db-instance \
--db-instance-identifier ${db_new_instance} \
--force-failover

Step11. Delete previous DB Instance

aws rds delete-db-instance --db-instance-identifier ${db_instance} --skip-final-snapshot

Conclusion

This post introduced how to restore from DB Snapshot using the AWS CLI.

Note ※From a DB snapshot, it is not possible to restore to an existing DB instance. The restore process must be done to a new DB instance. Since the endpoint of the DB instance will be changed, we add a CNAME to the endpoint so that the endpoint can respond by switching DNS. ※Since Microsoft SQL Server and Oracle have additional requirements, please check the document at the referenced URL below. ※Some commands such as restore-db-instance-from-db-snapshot have many parameters so please refer to the documents in the URLs below.

References

• Restoring From a DB Snapshot
• AWS CLI Command Reference | restore-db-instance-from-db-snapshot
• AWS CLI Command Reference | reboot-db-instance
• AWS CLI Command Reference | db-instance-available
• AWS CLI Command Reference | modify-db-instance