Is it possible to provision new ec2 instances to an existing ELB? - amazon-ec2

Is it possible to add new instances to an ELB?
I'd like to not have to destroy my elb, and update my cname records w/ namecheap if possible.

Yes of course. It would be extremely painful to scale-out your application if you couldn't do this. For a classic ELB, see the documentation here. For an ALB or NLB you simply register your new instance to the target group.

Related

AWS EC2 - Web App on Multiple EC2 with load Balancer

Currently I have setup my web application on my 2 instance (ec2). Both instance have same web module and also SSL certificate.
And then I also have setup 1 load balancer for both instance for high availability.
But I was wondering on domain name part. Because both instance have different IP, and right now I only assign 1 IP instance into our domain provider.
So basically do I need provide both instance IP into my domain provider? Sorry I was newbie on this domain part :(
wasabiz, since you are a newbie, I would suggest going with AWS Beanstalk path.
To answer your question.
You can use Route53 to create/import your domain Name. The domain can point to DNS name of the Loadbalancer. From there LB will route the traffic to your EC2 instances. You need to introduce the autoscaling layer and move the EC2 instances inside it. So that the auto scalaing requirements can be fulfilled. All these options are configurable in AWS BeanStalk.
You have options to generate TSL certificates in AWS which is free to be used in AWS infrastructure. Otherwise, if you already have a certificate, you can import the certificate into AWS through AWS Certificate Manager and use it where ever needed, eg:load balancer.

Terraform setup tips: TLS communication across VPCs

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.

Adding a CNAME to an AWS EC2 Public Domain Name

I have a test application running at
http://ec2-34-215-196-193.us-west-2.compute.amazonaws.com/
(This is a Test application, it wont be live for long. When I try to add a CNAME to this, like the screenshot below
. is added by the DNS system.
However, my app seems to be accessible only via us-west-2.compute.amazonaws.com or us-west-2.compute.amazonaws.com.
I can make it to resolve it either one of them.
But adding anything, does not seem to resolve with a CNAME. It gives 503 Service Unavailable.
I am using AWS EC2 to host the app with a HAProxy Load Balancer.
Using Google Domains for DNS Name.
Any suggestions for troubleshooting this problem?
All dns entries have a dot in the end like subdomain.domain.com.
It's not suggested to create CNAMEs to your ec2 instance because that IP may vary in time and it's not reassignable, that's what elastic ip's are made for, just create an elastic IP, assign it to your ec2 instance and assign it as an A record on your DNS provider.
Amazon AWS documentation
First create elastic IP and assign to your instance. Then create A record and point IP. Your site should work normal.

Should I use Amazon's AWS Virtual Private Cloud (VPC) [closed]

Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 3 years ago.
Improve this question
Currently moving to Amazon EC2 from another VPS provider. We have your typical web server / database server needs. Web servers in front of our database servers. Database servers are not directly accessible from the Internet.
I am wondering if there is any reason to put these servers into an AWS Virtual Private Cloud (VPC) instead of just creating the instances and using security groups to firewall them off.
We are not doing anything fancy just a typical web app.
Any reason to use a VPC or not using a VPC?
Thanks.
NOTE: New accounts in AWS launch with a "default VPC" enabled immediately, and make "EC2-Classic" unavailable. As such, this question and answer makes less sense now than they did in August 2012. I'm leaving the answer as-is because it helps frame differences between "EC2-Classic" and the VPC product line. Please see Amazon's FAQ for more details.
Yes. If you're security conscious, a heavy CloudFormation user, or want complete control over autoscaling (as opposed to Beanstalk, which abstracts certain facets of it but still gives you complete access to the scaling parameters), use a VPC. This blog post does a great job summarizing both the pros and cons. Some highlights from the blog post (written by kiip.me):
What’s Wrong with EC2?
All nodes are internet addressable. This doesn’t make much sense for nodes which have no reason to exist on the global internet. For example: a database node should not have any public internet hostname/IP.
All nodes are on a shared network, and are addressable to each other. That means an EC2 node launched by a user “Bob” can access any of EC2 nodes launched by a user “Fred.” Note that by default, the security groups disallow this, but its quite easy to undo this protection, especially when using custom security groups.
No public vs private interface. Even if you wanted to disable all traffic on the public hostname, you can’t. At the network interface level each EC2 instance only has one network interface. Public hostnames and Elastic IPs are routed onto the “private” network.
What's Great About the VPC
First and foremost, VPC provides an incredible amount of security compared to EC2. Nodes launched within a VPC aren’t addressable via the global internet, by EC2, or by any other VPC. This doesn’t mean you can forget about security, but it provides a much saner starting point versus EC2. Additionally, it makes firewall rules much easier, since private nodes can simply say “allow any traffic from our private network.” Our time from launching a node to having a fully running web server has gone from 20 minutes down to around 5 minutes, solely due to the time saved in avoiding propagating firewall changes around.
DHCP option sets let you specify the domain name, DNS servers, NTP servers, etc. that new nodes will use when they’re launched within the VPC. This makes implementing custom DNS much easier. In EC2 you have to spin up a new node, modify DNS configuration, then restart networking services in order to gain the same effect. We run our own DNS server at Kiip for internal node resolution, and DHCP option sets make that painless (it just makes much more sense to type east-web-001 into your browser instead of 10.101.84.22).
And finally, VPC simply provides a much more realistic server environment. While VPC is a unique product to AWS and appears to “lock you in” to AWS, the model that VPC takes is more akin to if you decided to start running your own dedicated hardware. Having this knowledge beforehand and building up the real world experience surrounding it will be invaluable in case you need to move to your own hardware.
The post also lists some difficulties with the VPC, all of which more or less relate to routing: Getting an internet gateway or NAT instance out of the VPC, communicating between VPCs, setting up a VPN to your datacenter. These can be quite frustrating at times, and the learning curve isn't trivial. All the same, the security advantages alone are probably worth the move, and Amazon support (if you're willing to pay for it) is extremely helpful when it comes to VPC configuration.
Currently VPC has some useful advantages over EC2, such as:
multiple NICs per instance
multiple IP's per NIC
'deny'-rules in security-groups
DHCP options
predictable internal IP ranges
moving NICs and internal IPs between instances
VPN
Presumably Amazon will upgrade EC2 with some of those features as well, but currently they're VPC-only.
VPCs are useful if your app needs to access servers outside of EC2, e.g. if you have a common service that's hosted in your own physical data center and not accessible via the internet. If you're going to put all of your web and DB servers on EC2, there's no reason to use VPC.
Right now VPC is the only way to have internal load balancers
If you choose RDS to provide your database services, you can configure DB Security Groups to allow database connections from a given EC2 Security Groups, then even if you have dynamic IP addresses in your EC2 cluster, the RDS will automatically create the firewall rules to allow connections only from your instances, reducing the benefit of a VPS in this case.
VPS in the other hand is great when your EC2 instances have to access your local network, then you can establish a VPN connection between your VPS and your local network, controlling the IP range, sub networks, routes and outgoing firewall rules, which I think is not what you are looking for.
I would also highly recommend trying the Elastic Beanstalk, which will provide a console that makes easy to setup your EC2 cluster for PHP, Java and .Net applications, enabling Auto Scaling, Elastic Load Balancer and Automatic Application Versioning, allowing easy rollback from bad deployments.
You have raised a good concern here.
I would like to focus on the viability in terms of cost...
What about the cost factor?
I think You will be paying for that server per hour. Even if you pick $20-$50 dollars a month instance it will be something you will pay the rest of your server life. The VPN server is something you can easily set on old hardware very cheap and even free for open source solution.
Adding VPN to existing AWS servers park make sense, setting a solo VPN server on AWS doesn't. I don't think it is the best cost-effective option but that just my opinion.
Thanks,
Alisa

Amazon EC2 autoscaling instances with elastic IPs

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!

Resources