Consider an server ec2-50-1-2-3.compute-1.amazonaws.com, which is not publicly available and which does not have an elastic IP address. I cannot assign it an Elastic IP address as I don't have any more addresses to assign (used all 5 already on publicly-available servers).
The publicly-available servers need to access a service on ec2-50-1-2-3.compute-1.amazonaws.com. However, if I restart that server then it may receive a different address and I'll have to update 20 websites across 5 webservers with the new address. Is there any way to refer to the ec2-50-1-2-3.compute-1.amazonaws.com server which will persist even if I restart that server, considering that I have no more Elastic IP addresses to assign to it?
Is there any way to refer to
Key word "refer to" -- indeed, there is... a DNS CNAME.
Whether your DNS is in Route 53 or elsewhere, a CNAME record refers a system asking for a particular host by name, to a different host -- also by name.
Let's say, for example, that the service this system provides is the generation of reports. In the "example.com" domain...
reports IN CNAME ec2-50-1-2-3.compute-1.amazonaws.com.
Any machine looking up "reports.example.com" from the DNS will be referred to the hostname ec2-50-1-2-3.compute-1.amazonaws.com which will of course resolve to the machine's IP address.
If the machine's IP address (and therefore, in AWS, its hostname) changes because the instance was terminated or failed or replaced, you only have to update the information in one place -- the DNS. The systems that need to access this system would be configured with "reports.example.com" instead of the other hostname, so they wouldn't have to be maintained individually.
If you are using Route 53, it's also possible to configure Route 53 to actually give out a different answer using failover routing with health checks and divert requests elsewhere when the instance isn't working properly.
Amazon will not give you any difficulty at all if you simply request more Elastic IPs. It's right here: Request to Increase Elastic IP Address Limit
It turns out the the best way to refer to other instances in AWS is to use Amazon Virtual Private Cloud (VPC). In VPC each machine gets a static internal IP address, which persists for the lifetime of the instance. In fact in VPC one can configure full networking!
Related
I followed all the steps given on the tutorial page of AWS to create a subdomain(https://aws.amazon.com/es/premiumsupport/knowledge-center/create-subdomain-route-53/) and I'm pretty sure I got everything right because the tutorial is pretty straight forward. For context, before this I setup a LAMP stack on the server linked with my main domain (example.com).
My question is how to upload and manage files on my subdomain (subdomain.example.com). I thought that all I needed to do was to create a new EC2 instance and link it with the "hosted zone" of my subdomain, and after that I could just upload files and it would work (like I did on my original instance of the main domain). But after many tries clearly I'm doing something wrong, because the page of my subdomain (subdomain.example.com) keeps appearing blank with just the text "This site can't be reached."
You say that you installed a LAMP stack on the instance, so presumably there is a web server listening on port 80.
To test this, first login to the instance via SSH, then try curl localhost to test the web server. If that fails, then there is a problem with your web server.
If it works, the you should check the Security Group associated with the Amazon EC2 instance. It should be allowing incoming traffic on port 80 from 0.0.0.0/0.
Next, obtain the Public IP address of the instance. In a browser on your own computer, try accessing the IP address, eg http://1.2.3.4. That should work if the Security Group has been correctly configured.
By the way, you should be using an Elastic IP address (EIP) for the EC2 instance, which is a 'static' IP address that does not change. You can create an EIP in the EC2 management console, then associate it with the instance. This prevents the Public IP address from changing if the instance is stopped.
Next, try accessing the instance via the domain name. If this does not work, then test the name resolution by using ping with your domain name. The Ping itself won't work, but it should display the IP address that is linked to that domain name. Make sure that the IP address matches the Public IP address you used in the previous step.
If no IP address is provided, then you are missing an A-Record in the hosted zone. You should create the A-Record in the hosted zone and provide it with the Public IP address of the instance.
Here's what's bothering me. Is there a better way than sending emails to devs that the ip address for their dev server has changed after the instance is stopped and started?
I was thinking of a single small instance that has an elastic ip which the devs can log in using terminal, and ssh again to the internal ip address of the dev server. Is that effective?
Does it mean that the devs need to be informed of the change every time?
It's unclear exactly what you are saying "there's a new public dns for the server"? -thanks for the comment, that's clearer what you mean! It's the aws domain name in the format "ec2-54-222-213-143.eu-west-1.compute.amazonaws.com" you are referring to
You are asking how can these name/address changes be managed?
Generally speaking for fixing these kinds of problems there are a couple of things to be aware of
Firstly, if it is the public ip address that is changing instead of an ephemeral public ip address use an elastic ip. This will stay the same and can be transferred from an old instance to a new instance. Please read http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/elastic-ip-addresses-eip.html about the differences between "Elastic IP" and normal public IP addresses on AWS
Secondly, if you are concerned about maintenance of the dns records that map the ip addresses to the domain names then it is possible to automate the updates to aws route53. I have used the aws cli command "route53 change-resource-record-sets" for this and also CloudFormation
Automating events to occur on instance start up does take a little research of the available APIs and hooks for example see this answer with a simple use of cloud-init Using cloud-init user data
I am new to all this. I have setup a Nginx server http://52.x.x.x I am testing it. I bought domain name from namecheap. I want domain name routed to the ip. What setting I should configure for this.
First, make sure your instance is associated with an Elastic IP (EIP). If you do not do that, your instance's public IP address will change each time you reboot. Here are the instructions from AWS on how to setup and assign an EIP:
http://docs.aws.amazon.com/AmazonVPC/latest/GettingStartedGuide/getting-started-assign-eip.html
Note that if you don't associate that EIP to a running instance you will be charged. You can reference EIP pricing here:
https://aws.amazon.com/ec2/pricing/
Next, as mbaird mentioned setup an A record in your DNS management at Namecheap.com. All you have to do is add an A record and enter the public EIP address that you received in the step above. As a start set your TTL (Time to Live) to 60 seconds. Here are the instructions on how to do that from Namecheap:
https://www.namecheap.com/support/knowledgebase/article.aspx/434/78/how-do-i-set-up-host-records-for-a-domain
You can use www.whatsmydns.net to help troubleshoot any DNS propagation. (i.e. It takes a while for all of the world-wide root DNS servers to know that your domain name points to 54.x.x.x)
And finally - just as a suggestion - don't post your IP address in a forum like this unless you absolutely have to. Instead write something like, 54.x.x.x.
I hope this helps!
I have an RDS instance with a URL that was provided by Amazon. (This URL has an IP that's associated with (of course)).
To make connecting to the DB easier I made a redirect from my domain like this: "db.myDomain.com" to the IP of the DB Instance.
For a week it all worked fine, but then, suddenly, it stopped working. After searching for a few hours, I have realized that the IP I was redirecting to was not the same as the IP of the instance.
This made me think that maybe the IPs on RDS are dynamic and the only way to access the DB is with the URL provided by Amazon.
Is this correct? If so, is there away to redirect from one URL to another?
Yes, your observation about the dynamic nature of the IPs for RDS is correct and it is the anticipated behaviour of the Service. Always use the URL provided for RDS instance to access it RDS instance(s).
For most of the use cases, you don't to do a redirect to access; as the DNS name would go inside a config file / connection string. If you still need a friendly name - you may use the Route53 to create an alias. Here is a documentation link from AWS to accomplish that [ https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-to-rds-db.html ] - it is easier & convenient.
For RDS instance, the DNS name is not changed, but IP address will be changed in some case, especially when you enable Multi-AZ (multiple available zone), the RDS instance will be switched to other available zone with different IP address when AWS found any fails in it.
So in your application, you can't fix the IP address for your database accessing, always set DNS (domain name) to access your database.
Scenario:
I have an EC2 server which houses the api currently setup to accept connections from several iPads. I do not wish for network sniffers to see the JSON requests that are being exchanged between the servers and the devices. The idea is to have a secure protocol in place so that communication will be secured.
I have been told purchasing a SSL certificate is the way forward. The Amazon server instance I have running has an address in this format:
ec2-xx-xxx-xx-xxx.ap-southeast-1.compute.amazonaws.com/
this is where my web root is with all the appropriate web service files. My webservice urls look something similar to this:
ec2-xx-xxx-xx-xxx.ap-southeast-1.compute.amazonaws.com/Agent/Create
so on so forth. There is no hosting plan whatsoever (in the case that information is necessary).
I have been recommended to buy an SSL Cert from http://www.Godaddy.com and have thought about getting the up to 5 multiple domains SSL certificate package.
Question: 1
What things do I need to be made aware of in order to make sure nothing fails?
I have recently read that I may need to associate an elastic IP address to my instance, otherwise the IP of my instance will change on reboots? And if that is the case, that means that the SSL certificate that was used for this: ec2-xx-xxx-xx-xxx.ap-southeast-1.compute.amazonaws.com domain would no longer work since the ip address would have changed upon reboot and therefor me losing my secure domain?
Question: 2
If my thoughts in question 1 stands true, then my question would then be what is the most user friendly way or lets say, the way for beginners to create a dedicated url for my server instance (so that 1) the domain name doesnt randomly change upon server reboot (not sure when i would reboot anyway) and 2) does this mean I can have easier webservice urls that one can remember? such as.... www.pk.com/Agent/Create instead of the long ec2 ugly url?!
Any easy to follow tutorials would be very helpful. I have looked at a few articles that spoke about elastic ip address, SSL certificates, and other articles about renaming ec2 url, but I'm in a position where I dont actually know which one applies to me. lol
Hope someone can help. thanks
What you want to do is to get an elastic IP address. This lets you bind your instance to a particular IP address when you start it up. You can then register a hostname in DNS (Amazon don't help you with this part) and state that that hostname has the IP address that is the elastic IP address that you have registered.
The final piece is to get a server certificate (strictly, a keypair where the public part is the server certificate) that has the hostname in the CN field of its Distinguished Name, and to install that server keypair on the instance. (This is another part that Amazon don't help you with, and is in fact the same process as if you were hosting the hardware yourself.) Like that, the client
looks up the hostname and gets the elastic IP address,
connects and gets the server certificate, and
checks the server certificate and sees that the hostname it is for is the hostname that they expected. (There's a few other checks as well, such as whether the certificate was signed by a trusted certificate authority and whether the certificate is within its validity period.)
That allows the client to trust that who they have securely connected to is who they expected to securely connect to, which is a key part of establishing trust.
What you do not do is use the AWS machine names (internal or external) in the certificate you apply for. Those change and you really do not want to trust other people's VMs.
Donal's answer is the way to go. You need to explicitly register a domain and generate the SSL certificate containing the CN as that domain. Elastic IP addresses definitely are your friends in this issue. You will need them.
I added another answer in order to give another point of view: if you ever want to scale your backend solution, going that way will be more difficult. If you ever thought about adding more servers to host your web service, you should definitely set up an Elastic Load Balancer, add your instances to it, and point the domain you just registered to your Elastic Load Balancer. Then, you can purchase the SSL certificate and install it directly on your ELB, configuring SSL termination on the ELB. You will also configure the ELB so that connections arriving at port 443 will map to port 80 (or whatever port) on your servers. Don't worry, this is plain easy to set up.
Whenever you want to add more servers to your web service, it will just be a matter of setting up another EC2 instance (this process can - and should - be automated) and adding it to the ELB.
With this setup, you get rid of the need for Elastic IP addresses. All the connections go through the ELB.