How to downsize an AWS RDS instance to free tier - postgresql

I want to create a free tier clone of a production AWS RDS PostgreSQL. As per my understanding, following are different ways
create a snapshot of the production DB and restore it on t2.micro
create a read replica of the production DB using t2.micro and then detach it as independent database
create a free tier database and restore a database dump of the production db
Option 3 is my last preference.
The problem is while creating read replica or restoring from snapshot, AWS doesn't explicitly allow to choose the free tier template. I just want to know if restoring to t2.micro without any advanced features like autoscaling, performance monitoring etc. is equivalent to free tier or not? I read here that the key thing with AWS production DB is that AWS provisions a secondary database provisioned to fallback in event of failure of the primary database or the Availability Zone in which the database is running.

AWS Free Tier doesn't actually care about the kind of service you use. Per their website you just get 750 instance hours per month for a db.t2.micro.
You can use these in any service you see fit and the discount will be applied automatically for the first 12 months.
Looking at the pricing page for RDS Postgres I can see, that these instances aren't listed anymore, which seems weird. The t2 instance family is fairly old, so they're probably trying to phase it out, but typically you can provision older instance types using the API directly if they're not available in the Console.
So what you want to do is create your db.t2.micro instance using one of the SDKs or the AWS CLI and restore from a snapshot. Alternatively you can create a read replica from the CLI and set the class to db.t2.micro. Later detaching that from the main cluster should work.
The production ready stuff refers to the Multi-AZ deployment, which is good for production use, but for anything production related a t2.micro seems like a bad choice, so I'm going to assume you're not planing to do that.

Related

how to setup replication instance in on premises postgres for master database in AWS RDS postgres?

I have a requirement of checking whether the exact copy of master database from AWS RDS can be created in on premises or not..
I have already established the connectivity between on prem and aws. Also checked the data migration using pg dump. But i am not getting how to create the replica without using DMS. Due to some security purpose we are not supposed to use DMS. So is there any other way out to implement thi ?
Any help will be much appreciated
It appears that your goal is disaster recovery.
Amazon RDS offers a few options for this:
Amazon RDS Snapshots are a backup of the database, stored in a region. If your database is in an Availability Zone that fails, the snapshot can be restored as a new database in another AZ. All AZs are physically separate data centers, much like your own data center is physically separate from an AWS data center.
Snapshots can also be copied to other Regions, which would guarantee a separation distance between data centers.
Multi-AZ Amazon RDS Databases keep a second copy of the data in another AZ and can switch-over to the alternate AZ without losing any data. This is faster than restoring a snapshot, but costs twice as much since two separate database servers are deployed.
These options would be easier to manage than replicating your data to an on-premises system. A Multi-AZ will automatically start the secondary instance, so your app can continue operating with only a short delay and no data loss. This is much better than you could offer if you fail-over to an on-premises system.

Will Serverless support AWS DocumentDB?

I work in a company that's using Serverless to build cloud-native applications and services. Today we use DynamoDB and SQL Databases with AWS Aurora.
We want to go with DocumentDB for our next application, but we could not find anything about Serverless and AWS DocumentDB. Does Serverless support AWS DocumentDB? If not, is there any plans to support it in the future?
Serverless supports any AWS resources that you can define using CloudFormation. As per the Serverless docs here:
Define your AWS resources in a property titled resources. What goes in
this property is raw CloudFormation template syntax, in YAML...
The YAML for creating a DocumentDB cluster is, going to look something like:
resources:
Resources:
DBCluster:
Type: "AWS::DocDB::DBCluster"
DeletionPolicy: Delete
Properties:
DBClusterIdentifier: "MyCluster"
MasterUsername: "MasterUser"
MasterUserPassword: "Password1234!"
DBInstance:
Type: "AWS::DocDB::DBInstance"
Properties:
DBClusterIdentifier: "MyCluster"
DBInstanceIdentifier: "MyInstance"
DBInstanceClass: "db.r4.large"
DependsOn: DBCluster
You can find the other CloudFormation resources that you can define in the resources parameter of your Serverless.yaml here.
DocumentDB is not a serverless service. You need to manage the backend server to use it.
Please refer to this blog: https://blogs.itemis.com/en/serverless-services-on-aws, you can see it is not in the list of "SERVERLESS SERVICES ON AWS".
No, this won't support serverless, if you really want this you can go with DynamoDB. Also, can see differences if you want.
DocumentDB
MongoDB is supported in this database, which provide ease to learn
Stored procedures are needed in this, where data retrieval and data accumulation is done with help
Document size is limited to 16MB and storage is maximized up to 64TB of data.
Daily backups are managed by the database itself, and can be recovered whenever required
This is costly as we require paying around $200/month even if the user uses only some instances of database or only used few hours.
AWS is not involved in the user credentials stored area as that will be stored in DB directly
Available in specific regions
Can be easily migrated out of AWS into any MongoDB
In case of primary node failure, service promotes read-replica to primary. Multi A-Z has to be configured by users. Backup can be copied across regions
DynamoDB
MongoDB is not directly supported i this and even not easy to migrate from MongoDB to DynamoDB
Stored procedures are not needed in this, which makes the process easier for users
There is no limit in the document size as it can be scaled up to the size of user requirements
Daily backups are not available which makes the user too backup the data which triggered explicitly by users, and can be recovered whenever needed
There is initial cost associated with this, but overall cost is less. Also, on-demand pricing is available where user manage with the lesser amount of $1/month. 25GB data is provided for free in first stage.
AWS controls the user access to the database through identity and access management where authentication and authorization is needed for low level as well
Available in all regions
Can not be easily migrated out of AWS into any MongoDB, you need to write a code to transform
Support global tables, which protect users against regional failure. Data is automatically replicated across multiple AZs in a single region.

How to setup cross region replica of AWS RDS for PostgreSQL

I have a RDS for PostgreSQL setup in ASIA and would like to have a read copy in US.
But unfortunately just found from the official site that only RDS for MySQL has cross-region replica but not for PostgreSQL.
And I saw this page introduced other ways to migrate data in to and out of RDS for PostgreSQL.
If not buy an EC2 to install a PostgreSQL by myself in US, is there any way the synchronize data from ASIA RDS to US RDS?
It all depends on the purpose of your replication. Is it to provide a local data source and avoid network latencies ?
Assuming that your goal is to have cross-region replication, you have a couple of options.
Custom EC2 Instances
You can create your own EC2 instances and install PostgreSQL so you can customize replication behavior.
I've documented configuring master-slave replication with PostgreSQL on my blog: http://thedulinreport.com/2015/01/31/configuring-master-slave-replication-with-postgresql/
Of course, you lose some of the benefits of AWS RDS, namely automated multi-AZ redundancy, etc., and now all of a sudden you have to be responsible for maintaining your configuration. This is far from perfect.
Two-Phase Commit
Alternate option is to build replication into your application. One approach is to use a database driver that can do this, or to do your own two-phase commit. If you are using Java, some ideas are described here: JDBC - Connect Multiple Databases
Use SQS to uncouple database writes
Ok, so this one is the one I would personally prefer. For all of your database writes you should use SQS and have background writer processes that take messages off the queue.
You will need to have a writer in Asia and a writer in the US regions. To publish on SQS across regions you can utilize SNS configuration that publishes messages onto multiple queues: http://docs.aws.amazon.com/sns/latest/dg/SendMessageToSQS.html
Of course, unlike a two phase commit, this approach is subject to bugs and it is possible for your US database to get out of sync. You will need to implement a reconciliation process -- a simple one can be a pg_dump from Asian and pg_restore into US on a weekly basis to re-sync it, for instance. Another approach can do something like a Cassandra read-repair: every 10 reads out of your US database, spin up a background process to run the same query against Asian database and if they return different results you can kick off a process to replay some messages.
This approach is common, actually, and I've seen it used on Wall St.
So, pick your battle: either you create your own EC2 instances and take ownership of configuration and devops (yuck), implement a two-phase commit that guarantees consistency, or relax consistency requirements and use SQS and asynchronous writers.
This is now directly supported by RDS.
Example of creating a cross region replica using the CLI:
aws rds create-db-instance-read-replica \
--db-instance-identifier DBInstanceIdentifier \
--region us-west-2 \
--source-db-instance-identifier arn:aws:rds:us-east-1:123456789012:db:my-postgres-instance

Move RDS instance from EC2-Classic to VPC

I am currently migrating my production system from EC2-Classic to VPC platform.
All is done except for RDS instance, which is still in EC2-Classic.
My original plan was to do migration with some downtime: shutdown all instances, take database snapshot, create new instance in VPC from this snapshot (RDS "Restore snapshot" feature).
Unfortunately when I tried to do this I realized that I cannot restore to the type of instance I want.
When I click "Restore" Amazon offers me only a limited number of options:
Expensive db.m3, db.r3 instances
Previous generation db.t1, db.m1, db.m2 instances
Ideally I'd like to create db.t2 instance, is it possible to do that somehow?
Also, is there a way to migrate with zero downtime? So far I've found nothing in Amazon docs.

Aws app with Heroku Postgres database

Is it possible to have an app running at aws EC2 and have it's database running at heroku's postgres?
In case it is, what are the downsides I should consider?
Since heroku is hosted at AWS, is there a way to know where is the location of the machine running my database?
Hosting my app in the same region of the database would help to keep the performance?
I would like to hear some opinions about this, I've been searching the topic without much success.
You can determine the public-facing location of your Heroku DB at any given time with a traceroute ... but there's no guarantee that it'll stay at that location, or that there isn't any internal re-routing going on. You'd probably want to speak directly with Heroku support about ways to make sure your Heroku DB instances are local to your AWS application instances, as that certainly would benefit performance. See if you can find out which availability zone, or at least which major region, they run the DB in, and whether you can "pin" your database instance to a given region/zone.
Amazon's RDS looks OK, but doesn't support PostgreSQL. Please keep nagging them to.
I'd probably just run the DB on AWS if performance wasn't particularly important. Use a raid10 of provisioned IOPS EBS volumes on an EBS-optimized instance and you'll get kind-of-ok performance (but at a really big price); alternately, you can use non-crash-safe ssd-based instance store servers and rely on replication and backups to keep your data safe.
I dont have any experience on Heroku PostgreSQL.
Generally of course you can run your own service on Amazon EC2 and use the managed database services of Heroku.
Downsides might be
nobody guarantees, that Herouku exclusively uses AWS and you probably can't determine the physical Heroku service location within the cloud so you will have to deal with network latencies
in addition to your external traffic fees you'll have to pay for the database traffic unless you talk to a server in the same availability zone in the same region
My suggestion ( without knowing any detail about the pros of Heroku )
Have a look at Amazon RDS if you don't want to run a database server on our own.
http://aws.amazon.com/de/rds/
I am operating around 70 server instances on AWS, both RDS and EC2 for more than a year now and I can't imagine any simpler way to keep your stuff running