I'm a backend developer who is a very beginner in Server Administrative here.
I have ec2 instance sitting on AWS with Elastic IP assigned to it.
There are several domains point to this Elastic IP (from my clients).
The server then, response with appropriate content.
At this point, I would like to start using load balance as the number of traffics is increasing.
The question is
Would I be able to apply Load Balancer while still not changing IP Address (Elastic IP) that domains pointing to?
I would be a bit difficult to get to all clients and ask them to update the DNS record point to new IP Address.
So having the same IP would be an ideal solution for me.
It will be a big help if you guys could shed light for me on this.
No. The ELB has a DNS entry that you can setup on your DNS provider or on Route 53. This DNS is the only external link to the ELB and ELBs don't have elastic IPs. Also, keep in mind that the DNS doesn't change on your ELB but the IP can change at discretion of Amazon.
Also, Amazon uses it's own internal mechanism to access instances behind load balancer and I'm pretty sure it doesn't use external addresses (most likely internal)
Another alternative is to setup your own HAproxy instance in EC2 and configure it with an Elastic IP, but that's a little bit more work. (Also, you have to monitor it closely as you would have to manage it in case of changes in traffic patterns)
Hope it helps.
Related
I have an instance running on premise and its IP address is changed regularly. My other services are running on AWS and they are using IP to connect to the premise's services. I have to update the IP address saved on AWS services whenever the IP is changed on premise network. I have a thought about using DNS but it is still a need to update A record.
I am looking for a way to do some auto-detect instead of manual updating. I wonder whether I can use load balancer to do the check. I know there will be a range of IP addresses on premise network. Can load balancer do a health check on these IP within the range? So my AWS service can send request to the load balancer. Is there any side-effect on this approach?
You need to use hostname instead of IP address as you mentoned the IP addresses keeps changing. AWS VPC can use a DNS forwarder like Unbound, which can forward the requests to your on premise DNS server when VPC resolution is unable to resolve the hostnames. This appraoch is quite effective as you send only those DN resolution to on-premise DNS that are missed by AWS VPC DNS.
Unbound allows resolution of requests originating from AWS by
forwarding them to your on-premises environment—and vice versa. For
the purposes of this post, I will focus on a basic installation of
Amazon Linux with the configuration necessary to direct traffic to
on-premises environments or to the Amazon VPC–provided DNS, as
appropriate. Review the Unbound documentation for details and other
configuration options.
Further reading : How to setup DNS resolution from AWS to on premise servers
It sounds like I cannot use an elastic ip with AWS Application Load Balancer.
I currently own a domain through GoDaddy and the DNS server points to the load balancer via the CNAME. However, if the load balancer dies and gets recreated, its url changes and I then have to change the CNAME and wait for the change to propagate.
There must be a solution around this - what is it?
It looks like the solution might be to use two load balancers - https://aws.amazon.com/blogs/networking-and-content-delivery/using-static-ip-addresses-for-application-load-balancers/, but this seems really excessive - I have a small application right now.
As far as I know, the only way to have a fixed static-IP for a LB is to use a Network Load Balancer.
As stated here
Support for static IP addresses for the load balancer. You can also assign one Elastic IP address per subnet enabled for the load balancer.
An Elastic Load Balancer retains its DNS name as long as you don't replace it manually. If you still want to have a temporary, low-cost solution to this problem, you can consider the following approach:
Assuming the application is deployed in a private subnet, I would proxy the traffic through an EC2 instance until your primary DNS changes propagate.
Launch a small EC2 instance and attach an Elastic IP to it (consider your bandwidth requirements to determine which size).
Configure a proxy (nginx) to forward traffic to your application.
Configure active-passive DNS failover using ELB DNS name and EIP.
How can I assign a static IP address to a ELB. Seems like I cannot.
Some articles online asks to create a Route 53 record but this requires changing CNAME of domain which also redirect email traffic. I just want to change A record not CNAME.
Some articles also mention that I can use a EC2 instance as a reverse proxy. But will a single proxy be able to handle a lot of traffic?
Any solution for this?
AWS' Elastic Load Balancer is actually elastic on two levels as described here:
http://shlomoswidler.com/2009/07/elastic-in-elastic-load-balancing-elb.html
The first level is the load balancer itself. In order to make sure that ELB can scale to whatever volume you have and burst to whatever volume you suddenly encounter, AWS assigns a 'static' DNS hostname (e.g. MyDomainELB-918273645.us-east-1.elb.amazonaws.com). That hostname points to multiple IP addresses. You can see that (from a command line) by running
$ host MyDomainELB-918273645.us-east-1.elb.amazonaws.com
MyDomainELB-918273645.us-east-1.elb.amazonaws.com 172.31.7.2
MyDomainELB-918273645.us-east-1.elb.amazonaws.com 172.31.11.33
The second form of elasticity within the ELB is obviously then ELB directing the query to one of your EC2 instances in the pool.
So, you can see that trying to assign a static IP address to the load balancer would be self-defeating.
Using an EC2 instance as a reverse proxy would also seem self-defeating as you would then create a bottleneck before even getting to the ELB. Might as well just create your own load balancer.
The recommended solution (which you've pointed out) is to create a CNAME that points to the ELB hostname (which won't change).
i.e. my-app.mycompany.com ->
MyDomainELB-918273645.us-east-1.elb.amazonaws.com
This would allow you to integrate your scalable application, behind the ELB within your domain.
I'm not sure I fully understand why you cannot create a CNAME in your DNS or what that has to do with directing email traffic, can you explain?
A new feature in AWS (I believe it was announced at Re:Invent 2017) allows for static IPs with Network Load Balancers (NLB). NLB can only handle layer 4 (TCP) and not HTTP specifics (layer 7).
You can assign one Elastic IP address per availability zone.
For details see the AWS blog post or the NLB documentation.
The "Classic Load Balancer" and "Application Load Balancer" do not support static IPs. If you need a feature only provided by those, you have to fall back to the CNAME solution described above.
A blog was recently published by AWS support on this topic leveraging NLB to provide static IP to Classic and Application load balancer - https://aws.amazon.com/blogs/networking-and-content-delivery/using-static-ip-addresses-for-application-load-balancers/
Summary of solution as described by the post
We end up with a TCP listener on a NLB that accepts traffic and forwards it to an internal ALB. The ALB terminates TLS, examines HTTP headers, and routes requests based on your configured rules to target groups with your instances, servers, or containers. The AWS Lambda function keeps everything in sync by watching the ALB for IP address changes and updating the NLB target group. In the end we’ll have a few static IP addresses that are easy for whitelisting, and we won’t lose any of the benefits of ALB. Note that we will be sending all of the traffic through two load balancers
I found setting up AWS Global Accelerator very straight forward and simple. It created 2 static IP Addresses and a static DNS pointing to my Application load balancer.
Configuring Global Accelerator
Set listeners as TCP port 80, 443
Select your load balancer endpoint (AWS Global Accelerator Configuration)
Add cname record for your dns pointing to the static dns it created
(mywebsite.com > globalacceleratorDNS.com). If any client needs to
whitelist, give them the 2 static IP it created
Pricing is $18 per month + a few pennies per GB of data transfer.
I'm pretty sure its cheaper than the NLB, Nat Gateway, Elastic IP setup.
https://docs.aws.amazon.com/global-accelerator/latest/dg/about-accelerators.html
For little traffic, it might be a solution to set up an EC2 Instance running Nginx as a forwarding proxy.
So you can use the EC2's static IP Address to forward your traffic resolving the ALB's DNS name.
However, it's a kind of a hack, but using a Global Accelerator or an NLB seems to me also like a hack :-)
Unlike the Network Load Balancer, the Application Load Balancer (ALB) does not support Elastic IPs, but that's not the worst part. If you use Route 53 together with the ALB, the DNS automatically sets the TTL to 60 seconds. This appears to be causing problems for our institutional - mainly government - customers running older Windows DNS servers. They just can't keep up with the ALB's Listener changing its public-facing IP on such a short notice. Older DNS infrastructure is either not respecting or is not capable of handling such aggressive TTL.
While I don't like it, AWS recommends to put a Network Load Balancer in front of the Application Load Balancer, per here: https://aws.amazon.com/blogs/networking-and-content-delivery/using-static-ip-addresses-for-application-load-balancers/
My question is simple. Does it make sense to have an Amazon Elastic Load Balancer (ELB) with just one EC2 instance?
If I understood right, ELB will switch traffic between EC2 instances. However, I have just one EC2 instance. So, does it make sense?
On the other hand, I´m using Route 53 to route my domain requests example.com, and www.example.com to my ELB, and I don´t see how to redirect directly to my EC2 instance. So, do I need an ELB for routing purposes?
Using an Elastic Load Balancer with a single instance can be useful. It can provide your instance with a front-end to cover for a disaster situation.
For example, if you use an auto-scaling group with min=max=1 instance, with an Elastic Load Balancer, then if your instance is terminated or otherwise fails:
auto-scaling will launch a new replacement instance
the new instance will appear behind the load balancer
your user's traffic will flow to the new instance
This will happen automatically: no need to change DNS, no need to manually re-assign an Elastic IP address.
Later on, if you need to add more horsepower to your application, you can simply increase your min/max values in your autoscaling group without needing to change your DNS structure.
It's much easier to configure your SSL on an ELB than an EC2, just a few clicks in the AWS console. You can even hand pick the SSL protocols and ciphers.
It's also useful that you can associate different security groups to the actual EC2 and the forefront ELB. You can leave the ELB in the DMZ and protect your EC2 from being accessible by public and potentially vulnerable to attacks.
There is no need to use a Load Balancer if you are only running an single Amazon EC2 instance.
To point your domain name to an EC2 instance:
In the EC2 Management Console, select Elastic IP
Allocate New Address
Associate the address with your EC2 instance
Copy the Elastic IP address and use it in your Route 53 sub-domain
The Elastic IP address can be re-associated with a different EC2 instance later if desired.
Later, if you wish to balance between multiple EC2 instances:
Create an Elastic Load Balancer
Add your instance(s) to the Load Balancer
Point your Route 53 sub-domain to the Load Balancer
With NO ELB :-
Less Secure (DOS Attacks possible as HTTP 80 will be open to all, instead of being open only to ELB)
You won't have the freedom of terminating an instance to save EC2 hrs without worrying about remapping your elastic IP(not a big deal tho)
If you don't use ELB and your ec2 instance becomes unhealthy/terminates/goesDown
Your site will remain down (It will remain up if you use ELB+Scaling Policies)
You will have to remap your elastic IP
You pay for the time your elastic IP is not pointing to an instance around $0.005/hr
You get 750 hours of Elastic Load Balancing plus 15 GB data processing with the free tier so why not use it along with a min=1,max=1 scaling policy
On top of the answer about making SSL support easier by putting a load balancer in front of your EC2 instance, another potential benefit is HTTP/2. An Application Load Balancer (ALB) will automatically handle HTTP/2 traffic and convert up to 128 parallel requests to individual HTTP/1.1 requests across all healthy targets.
For more information, see: https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-listeners.html#listener-configuration
It really depends on what are you running in the EC2 instance.
While with only one EC2 instance it's not necessary to use ELB (all your traffic will go to that instance anyways), if your EC2 service has to scale in the near future, is not a bad idea to invest some time now and get familiar with ELB.
This way, when you need to scale, it's just a matter of firing up additional instances, because you have the ELB part done.
If your EC2 service won't scale in the near future, don't worry too much!
About the second part, you definitely can route directly to your EC2 instance, you just need the EC2 instance IP. Take a look at the amazon route53 docs. Mind that if your IP is not static (you don't setup an Amazon Elastic IP), you'd need to change the IP mapping everytime the EC2 ip changes.
You can also use an ELB in front of EC2 if for example you want it to be publically reachable, without having to use up an Elastic IP address. As said previously they work well too with ASG's
I have a set-up running on Amazon cloud with a couple of EC2 Instances running through a load balancer.
It is important that the site has a unique(static) IP or set of IPs as I'm plugging in 3rd party APIs which only accept requests made from IPs which have been added to their whitelist.
So basically unless we can give these 3rd parties a static IP or range of IPs that the requests from the site will always come from then we would be unable to make any calls to them.
Anyone knows how to achieve this as I know that Elastic IPs are not compatible with load balancers?
If I were to look up the IP of the load balancer DNS name (e.g. dualstack.awseb-BAMobile-ENV-xxxxxxxxx.eu-west-1.elb.amazonaws.com resolves to 200.200.200.200) would that IP be Static?
Any help/advise is greatly appreciated guys.
The ip addresses of your load balancer is not static. In any event, your incoming load balancer IP wouldn't be used for outgoing connections.
You could assign elastic IPs to the actual instances behind the load balancer, which would then be used for outgoing requests. You get 5 free elastic ips, and I believe you can apply for more if you need them.
Additionally if using a VPC and if your instances are in a private subnet then they will only be able to access the internet via the NAT instance(s) you setup, and you can of course assign an elastic IP to the NAT instances
This is an old question, but things have changed now.
Now you can create a Network ELB to get a LB with a static IP.
from https://docs.aws.amazon.com/elasticloadbalancing/latest/network/introduction.html
Support for static IP addresses for the load balancer. You can also
assign one Elastic IP address per subnet enabled for the load
balancer.
https://aws.amazon.com/blogs/aws/new-network-load-balancer-effortless-scaling-to-millions-of-requests-per-second/
You can attache an additional ENI (Elastic Network Interface) to an instance in your VPC. This way the ELB (Elastic Load Balancer) routes the incoming Internet requests to the web server, and the additional ENI will be used to connect to your 3rd party (or internal) requests (Management network)
You can see more details about it in the VPC documentations
Really the only way I am aware of doing this is by setting up your instances within a VPC and having dedicated NAT instances by which all outbound traffic is routed.
Here is a link to the AWS documentation on how to set up NAT instances:
http://docs.amazonwebservices.com/AmazonVPC/latest/UserGuide/VPC_NAT_Instance.html
You CAN attach an elastic IP to the instances BUT NOT to the ELB (which is what the client sees).
You could use a full reverse proxy layer 7 load balancer like HAProxy:
Or a commercial implementation like Loadbalancer.org or Riverbed (Zeus)
They both are in the AWS Marketplace:
Your outbound requests to your 3rd party APIs will NOT go out via the ELB/ALB. That's for incoming connections. If you need an inbound static IP you'll probably need to forego the loadbalancer (or figure out how to implement Anshu's suggestion to attach an elastic IP to the loadbalancers, the doc is light on details). Update: I found some documentation that ALB use static addresses (and I just tried binding an elastic IP to one to be sure and that failed).
If you're talking about outbound connections see below:
If your server is deployed in a public subnet you can attach an
elastic IP to that host. Outbound communications will go out over
that address.
If your server is deployed in a private subnet there's
a NAT gateway attached to it. All outbound traffic from your private
subnet will go out over that interface.
You could use as already mentioned loadbalancer.org appliance in AWS. It would replace the AWS NAT instance and give greater functionality and include both Layer4 and Layer7, along with SSL termination and a WAF.
Best of all you get free support in your 30 day trial in AWS to help you get up and running.
Yes I am biased as I work for loadbalancer.org however I would say nothing ventured nothing gained.
You can use a DNS service like DNSMadeeasy that allows "ANAME" records. These act like an A Record but can be pointed at a FQDN or IP. So in this case you can point it to the ELB DNS.
Dave