I just started playing around with EC2, I created the keypairs and have no problems in my own laptop. But I just wonder how I can operate it from another computer.
Is that possible to send the keypair-file ,or simply export it from the AWS?
As it states on the EC2 Key pair page:
Amazon EC2 doesn't keep a copy of your private key; therefore, if you lose your private key, there is no way to recover it. If you lose the private key for an instance store-backed instance, you can't access the instance; you should terminate the instance and launch another instance using a new key pair.
Thus you can't export it again from the AWS Console. You would have to transfer the original one you downloaded when you launched the instance.
Related
I have an EC2 instance managed by Elastic Beanstalk, and I recently changed my key pair to a new one (findy-key-2) by modifying authorized_keys, because I lost my old private key (findy-key).
$ cat authorized_keys
ssh-rsa [my private key] findy-key-2
So right now I have ssh access to my own instance.
However, perhaps because I changed the key pair manually, it seems that EC2 doesn't recognize the new key pair name correctly. In the EC2 console, it still says the key pair name is findy-key, which I already deleted.
And because of that, I'm getting the error below when trying to upgrade to Amazon Linux 2 on the EB dashboard.
Configuration validation exception: Invalid option value: 'findy-key' (Namespace: 'aws:autoscaling:launchconfiguration', OptionName: 'EC2KeyName'): The key pair 'findy-key' does not exist
I noticed that under Elastic Beanstalk Dashboard > Configuration > Security, I can choose the new key from the EC2 key pair drop-down. But the warning message, Each of your existing EC2 instances will be replaced and your new settings will take effect then. implying that my current instance will be terminated, is frightening me because there might be some side effects such as loosing connection to my RDS volume (yes, I'm a newbie to AWS).
Hence, I'm trying to find a way to change the key pair name of an EC2 instance without terminating and creating a new one. If that's not possible, I want to know what are the possible side effects of replacing an EC2 instance.
Thank you.
For short term solution, you can use AWS Systems Manager Session Manager to login to your instances. For this you will need to add SSM permissions to your EB instance profile/role.
You can also try using EC2 Instance Connect which may work out of the box on the instances and you don't have to do anything special to use it.
But for the long term solution, you have to use EB options for that. The reason is that you instances run in Autoscaling group and they can be terminated at any time anyway. So if you are worrying about "some side effects", they you have to redesign your application so that it is stateless. This means that your application does not depend on any instance terminations and re-launch due to autoscaling events.
I solved this by creating another private key named findy-key (which is the name of the old key I deleted before) in AWS Console, and adding its public key in authorized_keys.
I have lost private key of my AWS instance.I searched the option in console panel.
I'm afraid you might be out of luck:
When you launch an instance, you should specify the name of the key
pair you plan to use to connect to the instance. If you don't specify
the name of an existing key pair when you launch an instance, you
won't be able to connect to the instance. When you connect to the
instance, you must specify the private key that corresponds to the key
pair you specified when you launched the instance. Amazon EC2 doesn't
keep a copy of your private key; therefore, if you lose a private key,
there is no way to recover it. If you lose the private key for an
instance store-backed instance, you can't access the instance; you
should terminate the instance and launch another instance using a new
key pair. If you lose the private key for an EBS-backed Linux
instance, you can regain access to your instance. For more
information, see Connecting to Your Linux Instance if You Lose Your
Private Key.
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-key-pairs.html
Yes, you can't recover the old key. Still, you can generate a new key to access that machine
When we loose private key, You can't login to that machine.
Please follow the below steps to recover the key.
Step 1) Detach your root volume from your machine using AWS console.
Step 2) Launch a fresh EC2 instance(Not from your old machine AMI)
Step 3) Attach your old volume to new EC2 machine
Step 4) Now login to new ec2 machine and mount the old EBS volume
Step 5) Now go to that partition then visit home directory inside that machine and go to .ssh folder.
Step 6) Now generate a new private and public key. Then paste public key into authorized_keys file.
Step 7) Once you done with above steps, detach that volume from this ec2 machine.
Step 8) Now attach this volume to your old machine as root volume
Step 9) Now try to login to your old machine with the newly generated key.
Hope it helps !!
Building off of this question:
https://unix.stackexchange.com/questions/24355/is-there-a-way-to-get-the-public-dns-address-of-an-instance
I know how to get an ec2 instance's own public DNS address. What I need is a way for this instance to get the public DNS instance of a second ec2 instance.
The idea is that I will have ~50 instances running, one or two of which will be a spot instance that is constantly running. All of the other worker instances need to know the spot, or master, instance's public DNS name to connect to it within my application. How can I do this?
On another note, is there a way I can create a backup of my spot master instance? In case it fails, I would like to have another spot instance that immediately takes its place, but my worker ec2 instances would have to update their information about the spot instance's public dns address.
I think the only way to get the public DNS of your other instance is by using the command line interface or Web API provided by amazon.
The concrete command you need is ec2-describe-instances which provides data about public DNS settings for each instance.
http://docs.aws.amazon.com/AWSEC2/latest/CommandLineReference/ApiReference-cmd-DescribeInstances.html
Of course you can do the same through the Web API:
http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-query-DescribeInstances.html
Regarding the backup you can map the spot instance to EBS (which is preferrable) and then make snapshot backups. The snapshot backups are still triggered manually in the amazon console (or again through command line tools and Web API). Snapshots should be good for regular backups.
You can also use a service like http://www.skeddly.com/ to automate your EC2 snapshot backups.
If you want to backup the full AMI image of your spot instance, so you can re-create it from scratch at a later time, or create multiple instances from the same image etc. go to the management console and do the following:
Click on Instances
Select the instance you want to create an AMI from
Click on "Actions" and select "Create Image"
Set the Image name and other info and save
An alternative is to use S3. When a spot instance comes up it will read its own public address and write it to a bucket in S3. The other instances will look up the bucket the first time they need it and use this value. If the spot instance goes down, the workers will poll the bucket periodically until a new spot instance comes up and updates the bucket.
Make sure to set the bucket to only allow authenticated access so only your applications can modify it.
This approach has a security advantage, as the VMs do not need access to your EC2 credentials. They only need access to a specific S3 bucket.
I lost my private key on a server because my hard drive was fried and I didn't have the folder with the key in it backed up. Consequently after research I found that I can make a snapshot of the EC2 instance and launch a new instance with a different key using the snapshot. I was able to do so and setup the new instance with a new key/pair. However, now I still cannot log on to the server through the Amazon client or with Putty SSH. Is there a there a time-frame I have to wait before the instance is SSH ready (i.e. 1 - 2 hours) or did I set it up wrong?
Thanks for any help.
When you ssh using windows m/c, then .ppk key is used and from unix systems .pem key is used.
You can try it once more from an ami, create an ami from the instance and if any ebs volume is attached, consider that too. Use that ami to launch and instance and provide the key at the end as it asks for, if your using the aws web console. In your case create a new keypair to be used and then assign it.
Wait is generally 2-5 minutes for the instance to be up and then try to ssh. Right click on the newly launched instance and check for the log file output. In some cases it can give you the hint.
It is generally preferred to use ebs backed volumes to avoid situations like data loss.
The thing is I have an ec2 instance with some public key inside ~/.ssh/authorized_keys to let developers ssh into this instance, but one day the autoscaling mechanism create a new instance and then drop my old instance(with authorized keys inside), and now I gotta edit the ~/.ssh/authorized_keys in the new instance again.
How can I prevent this? I mean how can I make sure whenever the autoscaling creating a new instance or dropping my old instance, it sync all of my authorized_keys, so that I don't need to do the manual copying.
Thanks very much.
I guess the AMI id which you have specified in the auto scaling contains old data. Create an AMI of your latest and update instance and remove the old AMI which you have already specified in the as-config and the add the latest AMI id. Thing will work fine.