Amazon RDS and VPC Endpoints Connectivity - amazon-web-services

I am having an Amazon RDS Postgres instance which resides in the default VPC.
To connect to it, i am using different EC2 instances (Java Spring Boot and NodeJs) running in ElasticBeanstalk. These instances also reside in the default VPC.
Do these EC2 instances connect to/query the RDS instance through the internet or the calls do not leave the AWS Network?
If they leave the AWS network and the calls go through the internet, is creating a VPC endpoint the right solution? Or my whole understanding is incorrect.
Thanks a lot for your help.

Do these EC2 instances connect to/query the RDS instance through the internet or the calls do not leave the AWS Network?
The DNS of the RDS endpoint will resolve to private IP address when used from within VPC. So communication is private, even if you use public subnets or set your RDS instance as publicly available. However, for connection from outside of AWS, the RDS endpoint will resolve to public IP address if the db instance is publicly available.
If they leave the AWS network and the calls go through the internet, is creating a VPC endpoint the right solution?
There is no VPC endpoint for RDS client connections, only for management actions (creating db-instance, termination, etc). In contrast, Aurora Serverless has Data API with corresponding VPC endpoint.

To secure your DB-Instances communications you need to be sure at least about the following:
locate your RD in private subnet (route table does not contain default outbound route to internet gateway).
RDS security group just accept traffic inbound only from instances security group/groups on TCP port for PostgreSQL which is usually 5432.
In this case Traffice to RDS will go localy in your vpc, for vpc endpoints it can be used to access RDS API operations privatly which is not your case (you just need to connect your app to DB using connection string)

Related

Is the connection from EC2 to AWS Service (like dynamodb) happening within the AWS Network, or via public internet?

I have VPC with couple of subnets containing EC2 instances.
The EC2 instances have code that invokes various AWS services like dybamodb.
Is the connection from EC2 to AWS Service (like dynamodb) happening within the AWS Network, or via public internet?
Is there any way to control this?
Is the connection from EC2 to AWS Service (like dynamodb) happening within the AWS Network, or via public internet?
Technically the process on EC2 would be hitting the AWS DynamoDB public API which is on the Internet. The traffic would be routed through the Internet Gateway you have attached to the VPC. I think if it is all in the same region it may not actually leave the AWS data center, and you could try testing that via tools like traceroute, but I don't think there are any guarantees of that.
Is there any way to control this?
Yes, add a VPC Endpoint to your VPC for the service you want to connect to. Then the DNS server in your VPC will route all traffic to that service over the VPC Endpoint, instead of routing it to your VPC's Internet Gateway. The traffic will then be guaranteed to stay within the AWS network.

how to connect a RDS outside VPC securely?

we want to our RDS outside VPC openly access, but it is not secure to do so.
Is there any solution to help us connect the RDS securely ?
You have two basic options to access an Amazon RDS database. Which you choose depends on your Risk appetite.
Option 1: RDS database in public subnet
For this option, the database is launched in a Public Subnet, with Publicly Available = Yes.
To secure the database, you would configure the Security Group to only permit inbound access from your IP address.
Option 2: RDS database in private subnet
For this option, the database is launched in a Private Subnet, with Publicly Available = No.
You will need some way to 'connect' to the VPC, and then connect to the RDS database. Options for connecting to the VPC could be:
Create an AWS Client VPN, which allows you to connect to the VPC from any location using an OpenVPN-based VPN client, or
Launch an Amazon EC2 instance in the public subnet and connect to it using SSH and Port Forwarding (See: How to use SSH Tunnel to connect to an RDS instance via an EC2 instance?)

Connect a Database with an Amazon VPC from local

Just created an VPC for EKS Cluster and started RDS PostgreSQL instance with custom VPC.
Custom VPC has Subnets.
My Custom VPC has Internet Gateway attached.
EKS and RDS is in same VPC so they have internal communication.
My problem is that i want to connect to RDS from my local machine and i am unable. Regarding the problem i have created a new Security Group with Inbound Rules for PostgreSQL.
PostgreSQL TCP 5432 0.0.0.0/0 –
Im still unable to connect
UPDATE
RDS is Publicly accessible
Security group allows access to RDS
In order to connect to RDS instances from the internet you need to do these 3 things
Deploy your RDS instance in a "public" subnet. This means the subnet must have an Internet Gateway attached to it so it can respond properly to outbound requests
In your RDS instance under Connectivity, extend the Additional configuration section, and then choose Publicly accessible.
Make sure the security group allows access to your RDS instance.
Note: exposing a database to public access is not secure. What I recommend you to do is create a proxy with haproxy or a VPN.
To be able to connect to the RDS database remotely you need to select "yes" option for the "Public Accessibility" setting for you database. Here are some additional configurations that need to be taken into account (form AWS docs):
If you want your DB instance in the VPC to be publicly accessible, you
must enable the VPC attributes DNS hostnames and DNS resolution.
Your VPC must have a VPC security group that allows access to the DB
instance.
The CIDR blocks in each of your subnets must be large enough to
accommodate spare IP addresses for Amazon RDS to use during
maintenance activities, including failover and compute scaling.
Best,
Stefan

Cross Account DMS Replication for RDS instances behind Bastion machines

I have production stacks inside a Production account and development stacks inside a Development account. The stacks are identical and are setup as follows:
Each stack as its own VPC.
Within the VPC are two public subnets spanning to AZs and two private subnets spanning to AZs.
The private Subnets contain the RDS instance.
The public Subnets contain a Bastion EC2 instance which can access the RDS instance.
To access the RDS instance, I either have to SSH into the Bastion machine and access it from there, or I create an SSH tunnel via the Bastion to access it through a Database client application such as PGAdmin.
Current DMS setup:
I would like to be able to use DMS (Database Migration Service) to replication an RDS instance from Production into Development. So far I am trying the following but cannot get it to work:
Create a VPC peering connection between Development VPC and Production VPC
Create a replication instance in the private subnet of the Development VPC
Update the private subnet route tables in the development VPC to route traffic to the CIDR of the production VPC through the VPC peering connection
Ensure the Security group for the replication instance can access both RDS instances.
Main Problem:
When creating the source endpoint in DMS, the wizard only shows RDS instances from the same account and the same region, and only allows RDS instances to be configured using server names and ports, however, the RDS instances in my stacks can only be accessed via Bastion machines using tunnelling. Therefore the test endpoint connection always fails.
Any ideas of how to achieve this cross account replication?
Any good step by step blogs that detail how to do this? I have found a few but they don't seem to have RDS instances sitting behind bastion machines and so they all assume the endpoint configuration wizard can be populated using server names and ports.
Many thanks.
Securing the RDS instances via the Bastion host is sound security practice, of course, for developer/operational access.
For DMS migration service however, you should expect to open security group for both the Target and Source RDS database instances to allow the migration instance to have access to both.
From Network Security for AWS Database Migration Service:
The replication instance must have access to the source and target endpoints. The security group for the replication instance must have network ACLs or rules that allow egress from the instance out on the database port to the database endpoints.
Database endpoints must include network ACLs and security group rules that allow incoming access from the replication instance. You can achieve this using the replication instance's security group, the private IP address, the public IP address, or the NAT gateway’s public address, depending on your configuration.
See
https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Security.Network.html
For network addressing and to open the RDS private subnet, you'll need a NAT on both source and target. They can be added easily, and then terminated after the migration.
You can now use Network Address Translation (NAT) Gateway, a highly available AWS managed service that makes it easy to connect to the Internet from instances within a private subnet in an AWS Virtual Private Cloud (VPC).
See
https://aws.amazon.com/about-aws/whats-new/2015/12/introducing-amazon-vpc-nat-gateway-a-managed-nat-service/

EC2 instance can't access to elasticache

As the title suggests, I'm struggling to connect to my elasticache instance via my EC2 instance. I have a orm to connect to redis in my EC2 instance that was just failing on my logs, so I sshed into my EC2 instance to try to manually connect to the redis instance and got a timeout:
Could not connect to Redis at <redis uri>: Connection timed out
They're in different VPC's (the elasticache instance and the EC2 instance), but in my elasticache instance's security group, I have a custom TCP inbound rule at port 6379 from any source.
Halp.
You setup the security rule, but did you setup the VPC peering properly:
A VPC peering connection is a networking connection between two VPCs
that enables you to route traffic between them using private IP
addresses. Instances in either VPC can communicate with each other as
if they are within the same network. You can create a VPC peering
connection between your own VPCs, or with a VPC in another AWS account
within a single region.
http://docs.aws.amazon.com/AmazonVPC/latest/PeeringGuide/Welcome.html
After you create VPC Peer connection, you also need to modify routing table.
Keep in mind that you need to modify BOTH of the routing tables.
Also you need to add CIDR of the local VPC.
It can be confusing which is "local" VPC and which is "target".
In my case, the local VPC contained EC2 instances that needed Redis database in other VPC. After creating peer connection in this format, I needed to do two things:
edit routing table for both local and target VPC.
edit security group of Redis database to accept connections from local VPC.
If set accordingly, you should be able to connect from EC2 instance at local VPC to Redis database in target VPC.
Here is documentation from AWS that is relatively easy to follow:
http://docs.aws.amazon.com/AmazonVPC/latest/PeeringGuide/vpc-pg.pdf
Your scenario can be found on page 16.