Is there any way to make new instances added to an autoscaling group associate with an elastic IP? I have a use case where the instances in my autoscale group need to be whitelisted on remote servers, so they need to have predictable IPs.
I realize there are ways to do this programmatically using the API, but I'm wondering if there's any other way. It seems like CloudFormation may be able to do this.
You can associate an Elastic IP to ASG instances using manual or scripted API calls just as you would any other instance -- however, there is no automated way to do this. ASG instances are designed to be ephemeral/disposable, and Elastic IP association goes against this philosophy.
To solve your problem re: whitelisting, you have a few options:
If the system that requires predictable source IPs is on EC2 and under your control, you can disable IP restrictions and use EC2 security groups to secure traffic instead
If the system is not under your control, you can set up a proxy server with an Elastic IP and have your ASG instances use the proxy for outbound traffic
You can use http://aws.amazon.com/vpc/ to gain complete control over instance addressing, including network egress IPs -- though this can be time consuming
There are 3 approaches I could find to doing this. Cloud Formation will just automate it but you need to understand what's going on first.
1.-As #gabrtv mentioned use VPC, this lends itself to two options.
1.1-Within a VPC use a NAT Gateway to route all traffic in and out of the Gateway. The Gateway will have an Elastic IP and internet traffic then whitelist the NAT Gateway on your server side. Look for NAT gateway on AWS documentation.
1.2-Create a Virtual Private Gateway/VPN connection to your backend servers in your datacenter and route traffic through that.
1.2.a-Create your instances within a DEDICATED private subnet.
1.2.b-Whitelist the entire subnet on your side, any request from that subnet will be allowed in.
1.2.c Make sure your routes in the Subnet are correct.
(I'm skipping 2 on purpose since that is 1.2)
3.-The LAZY way:
Utilize AWS Opsworks to do two things:
1st: Allocate a RESOURCE Pool of Elastic IPs.
2nd: Start LOAD instances on demand and AUTO assign them one elastic ip from the Pool.
For the second part you will need to have the 24/7 instances be your minimum and the Load instances be your MAX. AWS Opsworks now allows Cloud Watch alarms to trigger instance startup so it is very similar to ASG.
The only disadvantage of Opsworks is that instances aren't terminated but stopped instead when the load goes down and that you must "create" instances beforehand. Also you depend on Chef solo to initiate your instances but is the only way to get auto assigning EIPs to your newly created instances that I could find.
Cheers!
Related
I'm working for a client that has a simple enough problem:
They have EC2s in two different Regions/VPCs that are hosting microservices. Up to this point all EC2s only needed to communicate with EC2 instances that were in the same subnet, but now we need to provision our infrastructure so that specific ec2s in VPC A's public subnet can call specific ec2s in VPC B's public subnet (and vice versa). Communications would be calling restful APIs over over HTTPS/TLS 2.0
This is nothing revolutionary but IT moves slowly and I want to create a Terraform proof of concept that:
Creates two VPCs
Creates a public subnet in each
Creates an EC2 in each
Installs httpd in the EC2 along with a Cert to use SSL/TLS
Creates the proper security groups so that only IPs associated with the specific instance can call the relevant service
There is no containerization at this client, just individual EC2s for each app with 1 or 2 backups to distribute the load. I'm working with terraform so I can submit different ideas to them for consideration, such as using VPC Peering, Elastic IPs, NAT Gateways, etc.
I can see how to use Terraform to make these infrastructural changes, but I'm not sure how to create EC2s that install a server that can use a temp cert to demonstrate HTTPS traffic. I see a tech called Packer, but was also thinking I should just create a custom AMI that does this.
What would the best solution be? This doesn't have to be production-ready so I'm favoring creating a fast stable proof-of-concept.
I would use the EC2 user_data option in Terraform to install httpd and create your SSL cert. Packer is great if you want to create AMIs to spin up, but since this is an POC and you are not doing any complex configuration that would take long to perform, I would just use user_data.
Using Amazon VPC, what is the best possible way to attach multiple instances to a single ip address?
My company needs the ability to open/shutdown instances upon request and traffic. All instances created must have the same ip address attached, as the service I try to connect to allows only certain IPs that I can define every once in a while.
You want to use Elastic Load Balancer (ELB). It was built specifically for the purpose of balancing a large number of requests to the same IP across several EC2 instances.
http://aws.amazon.com/elasticloadbalancing/
If you want to whitelist the IPs of your instances to some other third party service, then you would have to use elastic IPs in that case. You can not associate one IP to more than one instance.
However, if you want only one endpoint for your service, you can very well use load balancer as also suggested above.
Can an Amazon EC2 instance process requests from and return results to an external client which may a browser or non-browser application? (I know that the EC2 instance will require a IP address and must be able to create a socket and bind to a port in order to do this.)
I'm considering an Amazon EC2 instance because the server application is not written in PHP, Ruby or any other language that conventional web hosting services support by default.
Sure it will. Just setup the security group the right way to allow your clients to connect.
Take a look at this guide: Amazon Elastic Compute Cloud - Security Groups
Also keep in mind: It's not possible to change the policy group after you created the EC2 instance. This feature is available for VPC instances only. See http://aws.amazon.com/vpc/faqs/#S2 for more information.
I have two EC2 instances from an Ubuntu image, they are located in different regions.
I just want to ask, whether they can communicate over the private IP addresses?
I have opened the required ports with a security group. I use netcat to test the communication, but it only works, when I use the public IP addresses.
It is not possible to communicate between Amazon EC2 regions via the private IP addresses (except if you setup a VPN and respective routing for this, see section VPN Solution below), traffic between regions is in fact passing the public internet and is not distinguishable from any other internet traffic, see e.g. the following FAQs from the Region and Availability Zone FAQ:
Can instances use group-based firewall rules across Regions? - No. Group-based firewall rules only work within a Region. If you need instances to communicate with each other across Regions, you should use CIDR based firewall rules. [...]
What is the cost for data transfer between Regions? - Data transferred from one Region to another is charged at both sides at the Internet data transfer rate.
This applies to an Amazon VPC as well, see e.g. the FAQ Can Amazon EC2 instances within a VPC in one region communicate with Amazon EC2 instances within a VPC in another region?:
Yes, as long as all communication takes place over the Internet
Gateway of each VPC and uses the Elastic IP addresses assigned to the
instances in each VPC. Please note: security groups cannot span
regions. All traffic filtering between instances in one VPC and
instances in another VPC must use the Elastic IP addresses as the
specified source or destination address. [emphasis mine]
VPN Solution
AWS has meanwhile released two walkthroughs describing a solution for Connecting Multiple VPCs with EC2 Instances based on either IPsec or OpenVPN:
Connecting Multiple VPCs with EC2 Instances (IPSec)
please note that this tutorial facilitates Openswan, but you can achieve the same with strongSwan (or even the Linux IPsec stack built in as of kernel 2.6+, see e.g. IPsec L2TP VPN server)
Connecting Multiple VPCs with EC2 Instances (SSL)
Now you can do it with AWS VPC peer connection.
It enables the resources in two VPCs that are in different regions, even in different accounts, to be able to communicate with the private IP address, just like in the same LAN.
One thing you need to know is the CIDR blocks you choose for your both VPCs, they must not be in conflict. Otherwise, the peer connection can't be made successfully.
See the official doc about VPC peer connection.
I want to use the Amazon Web Service free micro-instance for my different projects for testing and personal purpose. But I required some static-public IP on which I can run my server.
Is that possible? From where I can buy just IP and use it with my AWS?
EC2 Elastic IP Addresses
Elastic IPs are tied to an account, not an instance.
You need to look at AWS VPC for this.
Whilst VPC is free outside of the usual instance pricing, it doesn't work with Micro instances (the cheapest ones).
When not using VPC, you're assigned IP addresses through DHCP. When the DHCP lease expires, or you restart, your IP is released back to the pool.
VPC lets you use private IP addressing, you can use it with Elastic IPs and is much easier to integrate with a physical infrastructure setup.
If you're only testing/investigating AWS and have little or no budget to use anything other than a Micro instance, I'd just suck it up and deal with the changing of IPs.
If you've got a budget that lets you use instances other than Micro, then go for VPC.
Also, if you're doing more than testing/investigating I'd recommend starting with VPC straight away as trying to migrate from a non VPC to a VPC infrastructure is a massive PITA.
For every AWS account, 5 free elastic ips are provided. You have to just allocate them to required instance. But make sure that the allocate address(newly created elastic ip) in in use, because you will billed if the Elastic ip is not in use.
Looks like they have configured ARP statically so you can only use the IP address on an instance that was bound to that instance through the EC2 management console.
I just configured one of my instances to use a static IP address other than the one assigned through the management console and rebooted the instance.
I'm still receiving ARP responses on the old address but not receiving ARP responses on the new address at all.
Unfortunately for me, I have a not responding instance (NFS File Server) stuck in a stopping state while I attempt to terminate it.
The IP Address bound to that instance cannot be re-assigned to a replacement instance so now I have to reconfigure
On the whole pricing delima: When you come to think of it, there is a limited amount of static IPs so there must some pricing (supply and demand). This pricing is two fold: 1) for upto a limited number (5 per account) you don't have to pay. 2) if you created one you need to use it if you don't you'll be billed (to prevent every user to get 5 static IPs)