I was following a guide on connecting to Kafka from EC2 instance and one of the steps was to check if '/etc/krb5.conf' exists on my EC2.
On my EC2 instance it only exists folder '/etc/krb5.conf.d' but not '/etc/krb5.conf'. From internal discussion with several people - they believe it should exist by default. Not sure why my instance do not have it.
Should it exist by default once new EC2 (RHEL 7.3) is started?
If not - how to create it manually?
While I'm not sure why a /etc/krb5.conf doesn't exist by default on your new EC2 (RHEL 7.3), I will say on all instances of Linux I have ever seen that file exists as /etc/krb5.conf. What I would do is simply copy /etc/krb5.conf.d to /etc/krb5.conf. Please ensure that it is properly configured for your Kerberos realm - to do that see the MIT example here.
Related
I have an ec2 micro instance. I can start it from the console, ssh into it (using a .pem file) and visit the website it hosts.
Using the old ec2 CLI, I can start the instance and perform other actions including ssh and website access.
I am having trouble with the new ec2 CLI. When I do "aws ec2 start-instances --instance-ids i-xxx" I get the message "A client error (InvalidInstanceID.NotFound) occurred when calling the StartInstances operation: The instance ID 'i-xxx' does not exist".
Clearly the instance exists, so I don't what the message is really indicating.
Here is some of my thinking:
One difference between the old and new CLI is that the the later used .pem files whereas the new interface uses access key pairs. The instance has an access key pair associated with is, but have tried all the credentials I can find, and none of them change anything).
I tried created an IAM user and a new access key pair for it. The behavior in all cases is unchanged (start from console or old CLI, web access, ssh) but not using the new CLI.
I realize that there is a means for updating the access key pairs by detaching the volume (as described here), but the process looks a little scary to me.
I realize that I can clone another instance from the image, but the image is a little out of date, and I don't want to lose my changes.
Can anyone suggest what the message really means and what I can do to get around the problem?
The problem had to do with credentials. I had the correct environment
variables (AWS_ACCESS_KEY and AWS_SECRET_KEY) set. But they didn't match what was in my .aws/credentials file. That is, despite what it says here, the new CLI worked only when I had the environment variables and
the credentials file correct and in sync.
Configure your aws cli with "aws configure" in new cli instance with region in which your ec2 instance reside. and then try to give the same command. The instance should start.
I am windows user and wanted to use a spot instance using my own EBS windows AMI. For this I have followed these steps:
I had my own on-demand instance with specific settings
Using AWS console I used option "Create Image EBS" to create EBS based windows AMI. IT worked and AMI created successfully
Then using this new AMI I launched a spot medium instance that was created well and now running with status checks passed.
After waiting an hour or more I am trying to connect it using windows 7 RDC client but is not reachable with client tool's standard error that either computer is not reachable or not powered on.
I have tried to achieve this goal and created/ deleted many volums, instances, snapshots everything but still unsuccessful. Doesn't anybody else have any solution to this problem?
Thanks
Basically what's happening is that the existing administrator password (and other user authentication information) for Windows is only valid in the original instance, and can't be used on the new "hardware" that you're launching the AMI on (even though it's all virtualized).
This is why RDP connections will fail to newly launched instances, as will any attempts to retrieve the administrator password. Unfortunately you have no choice but to shut down the new instances you've been trying to connect to because you won't be able to do anything with them.
For various reasons the Windows administrator password cannot be preserved when running a snapshot of the operating system on different hardware (even virtualized hardware) - this is a big part of the reason why technologies like Active Directory exist, so that user authentication information is portable between machines and networks.
It sounds like you did all the steps necessary to get this working except for one - you never took any steps to cause a new password to be assigned to your newly-launched instances based on the original AMI you created.
To fix this, BEFORE turning your instance into a custom AMI that can be used to launch new instances, you need to (in the original instance) run the Ec2ConfigService Settings tool (found in the start menu when remoted into the original instance using RDP), and enable the option to generate a new password on next reboot. Save this setting change.
Then when you do create an AMI from the original instance, and use that AMI to launch new instances, they will each boot up to your custom Windows image but will choose their own random administrator password.
At this point you can go to your ec2 dashboard and retrieve the newly-generated password for the new instance based on the old AMI, and you'll also be able to download the RDP file used to connect to it.
One additional note is that Amazon warns that it can take upwards of 30 minutes for the retrieval of an administrator password after launching a new instance, however in my previous experience I've never had to wait more than a few minutes to be able to get it.
Your problem is most likely that the security group you used to launch the AMI does not have RDP (TCP port #3389) enabled.
When you launch the windows AMI for the first time, AWS will populate the quicklaunch with this port enabled. However, when you launch the subsequent AMI, you will have to ensure that this port is open for your security group.
I started an default instance of EC2 Wowza AMI (LINUX) and then I bundled/snapshot it via 'ec2-bundle-vol', uploaded it to s3 and registered the AMI.
When I start the bundled AMI with user data (zip file) with a script, it doesn't seem to execute it.
But when I start a default instance with the same user data (zip file), it works.
Does anyone know why my bundled AMI is not executing the user data I specify?
Thanks.
I'm not familiar with wowza or how they have their AMIs setup but...
On its own the ec2 user data does nothing - it only has relevance because a script running on that machine checks for the presence of the user data and does something with it.
Sometimes these scripts are set so that they only do stuff on the instance's first boot, they then drop a file somewhere so that on subsequent reboots the startup scripts aren't rerun.
If the wowza amis work on this basis then when you first boot up the ami this process is followed, so the data you've saved into the new AMI includes the "don't run startup scripts again" file. If this is the case you'd need to delete that file before creating your ami.
The user data mechanism on EC2 allows a script on the image to download the startup package as a file via HTTP from a link-local address (169.254.something) - if it's plaintext, it will execute directly. If it's compressed data, wowza startup will unpack it to /opt/working - the Wowza startup process is logged to wowzamediaserver_startup.log in Wowza's logs directory.
I had the same issue. Looking at our script I discovered that we were removing a cloud init dependancy in the script, making it a run once operation. The dependancy in question was boto.
I created an EBS-backed AMI from an Canonical Ubuntu Mavrick instance that was running with a keypair called us-west-01.pem
Then I started another instance using that AMI and at startup, assigned a new keypair to it called us-west-01.pem. However, when I tried to scp some data to the instance, I was able to get authenticated using us-west-01.pem:
scp -i /.ec2/us-west-01.pem -r /somepath/* ubuntu#myDnsValue:/somepath/
It also works with the correct us-west-02 key. I tried with another key, and it failed. The only explanation would be that the key used at the time of preparing the AMI is still accepted. How can I remove this so as to secure each instance with its own key?
Thanks in advance.
Depending on how you create the AMI (bundle or using rsync), you can remove or omit $HOME/.ssh/authorized_keys for the user ubuntu and root.
Following the instructions at http://aws.amazon.com/articles/1663?_encoding=UTF8&jiveRedirect=1 I created an instance with mysql's dbs running on an EBS volume.
I've been installing other software on the instance's filesystem (not the EBS volume) and would like to be able to save the whole it as an AMI.
In Elasticfox, both AMI commands were greyed out.
Is it not possible to do this?
I am not so familiar with ElasticFOX, but in general you cannot create an AMI of an EC2 instance created from instance-store explicitly. You need a series of ec2-ami-tools to create one. I have wrote a script which I used to create an AMI. Feel free to use.
Copy the following script:
https://github.com/rakesh-sankar/Tools/blob/master/AmazonAWS/AMI/CreateAMI.sh
-make sure, you update the following before use
Imagename Shortname
Path to priavetKey
Path to certificateKey
S3 User-id (in general, this is yourAWS account ID)
Bucket Name
Path to JavaHome
Give permission to the file.
chmod +x createAMI.sh
./createAMI.sh
It should create an AMI image under your account and register it with the name you have given.