I have a three-tier Windows-based web application bundled into 3 AMIs on Amazon EC2 that I use for load testing.
An ASP.NET web application on IIS
An .NET application server
SQL Server
After I launch them, the config files of each tier needs modifying to update the IP addresses.
At the moment I am doing this manually: I connect to the webserver instance via remote desktop and modify the config file to point to the new IP of the application server instance. Then I do the same with the application server to change the IP in the connection string.
This must be a common requirement and I must be missing something obvious. There must be a better way!
I could use Elastic IP addresses, but these machines are only provisioned for a couple of hours at a time, and I would be charged for the addresses when they were NOT in use (which would be most of the time).
Is there some way of persistently naming the machines? Can I somehow get all the machines on the same network and use machine names instead of IP addresses?
I could write some nifty PowerShell script that would perform the modifications remotely. Is there an example somewhere?
I could use a dynamic IP address service. I'm not sure if this would have any negative effect on performance or availability... Are there any downsides to this approach?
I could install some sort of self-configuring service on each machine (which connects to S3? SNS? SimpleDB?) to publish/retrieve the addresses of the other machines and update the config files automatically. Is there an example somewhere?
What is best practice?
You could use Amazon Virtual Private Cloud (Amazon VPC). You have a private subnet where you can assign an IP address to an instance, but it may require launching an instance from command line to assign IP. VPC is charged the same way as EC2.
Related
I'm just looking for advice, I can do most of my own research, but I'm not sure where to start. Here's the situation:
I want to be able to deploy 3 vms that have 2 nic's a piece. 1 nic will have a standard IP that AWS provides. The second nic will have a pre-configured internal static IP. Let's say, 192.168.0.100, 101, and 102. That way each vm can talk to each other automatically without needing to know what the external IP is. The purpose of this is so that I can have a small cluster already configured and I won't have to do a lot of work every time I deploy the cluster.
I want this to be repeatable. Let's say I want this for a classroom. Each student has the identical set of clustered VMs. All they need to do is power them on and start working.
So, I think I can do this with Terreform. I don't know if AWS has it's own tooling that can do this also. If it has, I haven't been able to find it yet.
Any suggestions would be greatly appreciated!
In general, every VM gets a private IP, if the VM is public you can assign a public IP which makes the VM accessible from external and also provides internet access, this is be done by source/destination NAT.
https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Internet_Gateway.html
As long as they are part of you VPC CIDR and available you can specify the IP addresses on instance launch. This can be done via AWS Console, API, CLI, CloudFormation and also with Terraform. The AWS native tools for doing it at scale / repeatable is CloudFormation or maybe also a script that runs AWS CLI commands would work.
https://awscli.amazonaws.com/v2/documentation/api/latest/reference/opsworks/create-instance.html
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-network-interface-privateipspec.html
I am planning to migrate from Ec2 classic to EC2 VPC. My application reads messages from SQS, download assets from S3 and perform actions mentioned in the SQS messages and then updates RDS. I have following queries
Is it beneficial for me to migrate to Amazon VPC from Classic
I create my EC2 machines using ruby scripts, and deploy code on them using capistrano. In classic mode I used the IP address to deploy code using capistrano. But in VPC there is a concept of private IP address and you cannot access a machine inside a subnet.So my question is:
How should I deploy code on the EC2 instances or rather how should I connect to them?
Thank You.
This questions is pretty broad but I'll take stab at it:
Is it beneficial for me to migrate to Amazon VPC from Classic
It's beneficial if you care about security of your data in transit and at rest. In a VPC none of your traffic is exposed to the outside and you can chose which components you want to expose in case you want to receive traffic/data from the outside. i.e Your ELB or ELBs.
I create my EC2 machines using ruby scripts, and deploy code on them using capistrano. In classic mode I used the IP address to deploy
code using capistrano. But in VPC there is a concept of private IP
address and you cannot access a machine inside a subnet. So my question
is: How should I deploy code on the EC2 instances or rather how should
I connect to them?
You can actually assign a public IP to your EC2 machines in a VPC if you choose to. You can use that IP to deploy your code from the outside.
You can read about it here: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-ip-addressing.html
If you want more security you can always deploy from a machine in your VPC (that has SSH access to the outside). You can ssh to that machine and then run cap deploy from there.
I'd like to host my own DNS name server to have total control on the DNS settings.
Is it a good idea to create a Windows 2012 VM (Iaas) on Windows Azure and use it as a DNS name server?
Problems I forsee:
Windows Azure SLA requires at least two instances? Not really a problem if the VM is down for < 20min since DNS should be cached downstream.
Azure VM Size? Extra small should do.
Changing IPs? Once you have the VM set up, Azure should not change your IP address unless you delete it.
Reverse DNS? I don't think hosting a nameserver requires a reverse IP DNS lookup.
Anything else? not really knowledgeable about hosting a DNS server, but I think it should work!
What am I missing?
Azure IaaS VMs have an SLA with a single instance, so you wouldn't need to worry about that.
Don't use extra-small for anything except development and testing. Network performance is erratic, ranging from very poor to non-existent.
The IP address will remain constant while the VM is deployed, yes.
However...
Are you talking about an internal DNS server, or a public nameserver? If the latter, hosting in a cloud datacenter is probably not the best approach. You'd be better off using a dedicated DNS provider like Zerigo.
I've set up 2 instances of Windows Server 2008 on EC2. I want one to act as the database server and the other as the client. For the client app to work it needs to be able to connect to the server instance with ALL of these things:
IP address of the database instance
access through a given UDP port
server name e.g. \\MyServer
an actual physical path through to its database e.g. \\UNC\SharedFolder\MyDatabaseFolder
I'm a complete novice with EC2. Is there anyway I can set this up?
Many thanks
At least three of the four are completely possible and I have worked with similar setups. Maybe someone else knows more about the UDP bit.
IP address of the database instance
That is standard on EC2. All instances have two network interfaces, one EC2 internal and one to the outside world. For communication between instances use the internal one. Data traffic over these interfaces is free.
Access through a given UDP port
I have never tried UDP communication in EC2, but if it works you should probably keep it within a local network of your own, i.e. a virtual private cloud (VPC).
Server name e.g. \MyServer
This kind of host name lookup does not need a name server, although you certainly could run one (preferably within a VPC). If you put the server name and (internal) IP into your hosts file (%systemroot%\system32\drivers\etc\hosts) you don't need a name server, though.
An actual physical path through to its database e.g. \UNC\SharedFolder\MyDatabaseFolder
Folder sharing should work the same as with any other Windows machine, but even that should probably be kept within a VPC.
Setting up a VPC can be a little steep to start with, but the documentation is good and the hard bits are often not needed (such as VPN tunnels). Have a look at the example scenarios and follow the one best matching your needs.
Amazon only gives you a certain number of static ip address and the local (private) ips of each EC2 instance can change when the machine is restarted. This makes creating a stable platform where EC2 instances depend on each other ridiculously hard to use as far as I can tell.
I've search online a lot about various solutions and so far have found nothing reasonable outside of assigning an elastic ip address on ever EC2 even if its not public facing. Does anyone have any other good ideas that is actually easy to execute on?
Thanks!
See the AWS team's response to question Static local IP:
The internal IP address of EC2 instances is allocated via DHCP. On
instance shutdown, or when the DHCP lease expires, the IP address is
returned to the general EC2 DHCP pool of addresses available for other
instances.
There is no way to guarantee that you will obtain the same DHCP
address across reboots.
Edit: The answer is to use Amazon VPC. There is no downside except a trivial amount of extra setup because now you control the router. It's a world apart from plain old EC2 instance on AWS. It's so necessary in fact that VPC will be enabled for all future AWS setups by default. See this post for more information: http://www.reddit.com/r/aws/comments/1a3n0r/ec2_update_virtual_private_clouds_for_everyone/
The stock answers are:
Use AWS VPC so you have complete control over instance addressing
Use Elastic IPs, which will resolve to the instance's local address (not the public, as you'd expect) when used to communicate between EC2 instances
I stumbled upon third option. There's ec2-ssh by the Instragram folks. It's a python shell script that you install globally and lets you both query the public dns of your ec2 instances by tag name and also ssh in via tag name as well.
The documentation for it is virtually nonexistent. I've written down the steps to install below:
To install ec2-ssh:
sudo yum install python-boto (python wrapper for ec2 api)
git clone https://github.com/Instagram/ec2-ssh
In your ~/.bash_profile set your AWS access key and secret like so:
export AWS_ACCESS_KEY_ID=XYZ123
export AWS_SECRET_ACCESS_KEY=XYZ123
cd into the bin folder of the repo, there will be two files:
ec2-host and ec2-ssh
copy them to your /usr/bin or /usr/local/bin.
Now you can do awesome stuff like:
$ ec2-host ZenWorker
ec2-999-xy-999-99.compute-1.amazonaws.com
and
$ ec2-ssh ZenWorker
Connecting to ec2-999-xy-999-99.compute-1.amazonaws.com.
Note that in your regular shell scripts you can use backticks to call these global tools. I've timed these calls and they take between 0.25 and 0.5 second using an EC2 instance, so that's really the only downside. Perhaps you can live with the delay, or use the fact that public DNS only changes for an instance on reboot to work up a solution.
Note that these two programs are commandline scripts and you don't need any Python knowledge to use them. For PHP fans, or those that also want an easy way to scp files without knowing the changing public DNS, you can checkout ec2dns.
I was in the same situation once. I still dont have the expertise to solve it properly. My ugly solution was to use elb not really for load balancing but just for the endpoint.
But I think a good solution can be obtained by using aws vpc.
Here's another Ruby solution for Updating Route 53 DNS from instance on AWS. You shouldn't reference raw 3rd party system IP addresses in your applications or server configurations.
you can change Ip Address using Elastic Ip:
You Can Do Using C# Code:
var associateRequest = new AssociateAddressRequest
{
PublicIp = your Elastic Ip,
InstanceId = Your Instance Id Which You Assign
};
amazonEc2Client.AssociateAddress(associateRequest);
after That DeAssociate It.
var disAssociateRequest = new isassociateAddressRequest(publicIp.ElasticIpAddress1);
AmazonEc2Client.DisassociateAddress(your Elastic Ip);
your Public Ip Will Change