EC2 how to swap your elastic IP - amazon-web-services

I have two instances. They are going to run the same app, but one is set up with a slightly different configuration. Right now I can go to their assigned elasticip and see that my site works on both. Th eonly other difference is that one is a micro instance and one is a small instance. Also, I have a bunch of DNS records pointing my domain name to the ip of the micro instance.
But what I want to do is swap them so that the small instance is now my main instance that has my domain pointing to it. I was hoping I could just disassociate the ip's and then reassociate the ip's only flipped around. But when I do that and then try to go to my domain.com I just get an error page. When I swap them back they both seem to work again. Is there something a more complicated I have to do?
edit:
When I try to SSH I also get all this stuff:
###########################################################
# WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! #
###########################################################
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
d6:ed:23:65:9c:da:0c:1b:2d:94:34:18:4d:68:8f:a5.
Please contact your system administrator.
Add correct host key in /Users/croberts/.ssh/known_hosts to get rid of this message.
Offending RSA key in /Users/croberts/.ssh/known_hosts:17
RSA host key for 54.183.212.154 has changed and you have requested strict checking.
Host key verification failed.
Something nasty! haha.

The error message is indicating that the remote computer does not match the computer previously recorded in the known_hosts file.
When using ssh, each computer generates a fingerprint and this is recorded against the computer identifier (eg IP Address) that you are using to connect to the remote machine.
If you are switching an Elastic IP address between instances and also using the Elastic IP address to ssh into the instance, then the error quite correctly is warning you that the computer is not the same computer to which you last connected on that address.
You can remove the offending entry from the known_hosts file, or even delete the whole known_hosts file (which admittedly will remove such warnings even if they are legitimate).

You should have no problem swapping the elastic IP from one instance to another. It can take a few minutes to take effect, so make sure that you can reach the correct instance before testing.
You don't describe the error, but if you are using name-based virtual hosts, and are using a different name, that could be one cause. If you restart apache after swapping EIPs, does the problem go away?
Finally, to fix the ssh error, remove the entry from the known_hosts file - if you read the error message, it's on line 17.

Related

Tensorboard: The requested URL could not be retrieved

I have tensorboard summaries saved in D:\0. I launch tensorboard from cmd, change the drive from C to D and launch tensorboard --logdir="D:\0". The problem is, tensorboard sometimes works, sometimes I get the error:
ERROR
The requested URL could not be retrieved
The following error was encountered while trying to retrieve the URL: http://nsv:6006/
Unable to determine IP address from host name nsv
The DNS server returned:
Name Error: The domain name does not exist.
This means that the cache was not able to resolve the hostname presented in the URL. Check if the address is correct.
Your cache administrator is webmaster.
One time to fix it, I change the computer name restarted the laptop and it worked. But I don't want to do this everytime. Is there a simpler solution?
OK. This is really silly. The reason for this error seems to be because I am connected to VPN to access lab servers. Once I disconnect from the VPN, tensorboard works.

Cassandra C++ connector: Address changed

I'm having some trouble with Cassandra's C++ connector. It is set to connect to a cluster (e.g. 10.0.0.10 and 10.0.0.11). One of the hosts has changed address (it's now 10.1.1.10). I've already updated cassandra's configuration, removed 10.0.0.11 from the peers table. Nodetool is already showing the correct cluster configuration.
Yet, the C++ connector keeps complaining about connecting to 10.0.0.11. I have no idea where to find that. Since no production data has been involved (yet), I've destroyed all the data directories and recreated keyspace. Still, this appears to be cached somewhere.
The parameter broadcast_rpc_address in the file cassandra.yaml was set to the old IP address.
This was enough to make the client search for the old IP address. This happens only when the host 10.0.0.10 was the contact point.

KAA MongoDB server, Data not retrived sent from Raspberry Pi

I am running this example http://kaaproject.github.io/kaa/docs/v0.10.0/Programming-guide/Your-first-Kaa-application/ .
But data is not storing on the server side.
What should I do now?
When I running db.logs_my_application_token.
find() from mongo console,
it is showing nothing.
Do I have to provide some IP or host in my code, I am using KAA SANDBOX from AWS.
Console Output of Raspberry Pi attachedenter image description here here...
Finally I am able to do that using ..
Perform these two steps may be this can solve your problem.
Just run this command on host machine
sudo /usr/lib/kaa-sandbox/bin/change_kaa_host.sh $new host name/ip$
Then change the IP address of using Admin UI, for that you need to
sign in using username : kaa and passwword : kaa123
then go to setting > general setting then change the IP address preceded by :8080, enter your machine's public IP address, that can be easily accessible from anywhere.
Tips :: if you are using AWS instance then use public IP address of your instance.
Further error persist then drop your previous instance and launch a new instance.
For more details go the official documentation page
Hope it will be helpful for you.
You do not need to provide IP address.
You should download the generated SDK file and compile it with the source code. and then run it.

get IP address of local machine on c++

I want to retrieve IP address of my computer (same as I get on http://www.whatsmyip.org/)
I have a win32 project.
This is the code that I am using, as I didnt find any tutorial on this, I could get following info, but not the IP address which I saw for my computer on the whatsmyip.org :(
The IP I got on whatsmyip.org starts with 116.x.x.x
Your code gets adapter addresses, which are local. If you want your Internet address, you need to use the Internet, not your local network. You need to replicate the functionality of asking an external site what IP it sees you connecting from. See here for some suggestions for how to do that.
Retrieving http://icanhazip.com will do it. You can use whatever HTTP library you like.
The IP which assigned to your machine is not necessarily the IP that you see outside of your local network (e.g. in whatsmyip.org).
Your machine is not directly connected to the Internet with a valid and static IP. Maybe you are behind a NAT. So you can not determine your valid IP over Internet by listing your local assigned IPs in many situations.
To findout what IP address you have in Internet, you can do two ways. Ask from someone over Internet (for example, using whatsmyip.org). Or, query your local network recursivly (which is not easy task)

ssh: connect to host heroku.com port 22: No route to host

Hi I in an attempt to connect to more than one heroku account I did a number of stuff that has led to this error. "ssh: connect to host heroku.com port 22: No route to host" I dont know what the problem is or how to solve it so I want to start all over with heroku and ssh keys on my machine. How to I delete the present configurations and start afresh?
A few things I would attempt to do:
Ensure that there is no quirky setup in your HOSTS (/etc/hosts) file that is causing confusion
Check your ~/.ssh directory and ensure that the keys you expect to be there ... are there.
Check your ~/.ssh/config file for any incorrect information
Ensure that your heroku SSH server is actually listening on port 22. A lot of people will change the default SSH port for security purposes.
Ensure that the private key that you're attempting to use is uploaded to the heroku server. Some SSH instances won't tell you that it's an invalid key for security purposes. Instead it will just give you the rejection message you mentioned.
If I think of any other diagnostics I'll be sure to update.
Best of luck.
Perhaps something is set oddly in your $HOME/.ssh/config file. You can try backing up this file and then removing it to see if it resolves your problem.