I have Cassandra cluster on AWS. I have it only for testing purposes. Because of that I need to stop my instances and start them some other time. I deployed cluster with Datastax AMI and everything seems alright. I stoped instances in EC2 Management console and waited for 'stoped' state. After that I started them. I connected to them and Cassandra did not work. Command nodetool could not reach localhost:7199. Security groups on AWS allow all inbound and outbound traffic. I tried to sudo service cassandra start, but I got the same error.
I need start all nodes of cluster without manual action on them.
Ah. You stopped instances from the EC2 management console. This erased everything from the ephemeral storage. You should only restart instances if necessary, but never stop them. Or use sudo service dse restart to restart the dse service only without restarting the entire instance. Now I'd suggest that your best bet is to redeploy the cluster (or at least this node) from scratch....
Here is some explanation of what the instance store (ephemeral store) is: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/InstanceStorage.html
The data in an instance store persists only during the lifetime of its
associated instance. If an instance reboots (intentionally or
unintentionally), data in the instance store persists. However, data
on instance store volumes is lost under the following circumstances:
Failure of an underlying drive
Stopping an Amazon EBS-backed instance
Terminating an instance
Datastax uses the ephemeral storage to store data and commit logs, because this storage is much faster than the ebs storage. More details here: http://datastax.com/documentation/datastax_enterprise/4.6/datastax_enterprise/install/installAMI.html
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When I'm using AWS Cloud9, an EC2 instance is running in the background hosting it. By default, the EC2 instance hibernates after 30m, but sometimes I just want to use the IDE for 2 minutes and not have the EC2 instance running for 30m afterwards. Can I reduce the threshold for hibernation further or hibernate the EC2 instance manually?
Assuming you have Cloud9 running on its own on-demand EC2 instance (the default setting during setup), you can find the EC2 instance backing it in your EC2 management console and shut down the instance manually when you're done with it.
I am deploying Wordpress site using LAMP AMI on EBS-backed EC2. Wordpress database will be stored in EBS.
Amazon keeps on updating base configuration of EC2 for better performance & security.
If I have to upgrade my EC2 then my EBS will get deleted.
How can I ensure that my EC2 gets updated without affecting my EBS?
EBS Snapshot is not of any help as new EC2 already has a EBS attached.
Do I have to always migrate my Wordpress site using backup & do this upgradtion?
Amazon EC2 instances use EBS volumes as their disk volumes. They are populated from an Amazon Machine Image (AMI) when the instance is launched.
When AWS releases updated AMIs, any new instance launched from the AMI will contain the updated disk content. However, existing EC2 instances will not be changed (since they have a copy of the AMI at the time that the instance was launched).
You can also change the Instance Type of an EC2 instance, which gives it different hardware (CPU, Memory). This can be done by stopping the instance, changing the type and starting it again. This will not affect the contents of EBS volumes.
If you wish to keep your instance "current", simply run sudo yum update (Linux) or run the Windows Update utility to update your operating system and associated utilities rather than launching a whole new instance.
I had to stop my m3.medium EC2 instance from the AWS console to resize it to m3.large. However, after it stopped, it automatically created a new instance.
Any idea why this is happening? It caused some big troubles for me.
Your AutoScaling group with minimum size = 1 spun up a new instance because there were no instances in the 'running' state available to respond to requests, particularly health checks. Your instance was deemed 'unhealthy' and replaced by the ASG.
If your instance storage was ephemeral, I'm afraid it is gone forever unless you recently saved an AMI. If your instance storage was backed by EBS, you can recover it by attaching the EBS volume to a new instance.
In the future, consider configuring your autoscaling group's launch configuration to have everything you need ahead of time, by either bootstrapping the instance or by baking an AMI.
For 'bootstrapping' an instance:
Create a new launch configuration with a standard AMI avaialble from Amazon.
Add user data to the launch configuration to handle installation and configuration of your desired programs.
For 'baking' an AMI:
Install your desired programs and configuration on a new EC2 instance.
Take an image (AMI) of that EC2 instance.
Use that image in your new launch configuration.
Manually working on an instance within an ASG and expecting the instance to persist indefinitely is dangerous, as you've just discovered.
Further Reading:
EC2 Documentation - AutoScaling Health Checks
EC2 Documentation - Amazon Machine Images
I have a requirement of setting up Apache Tomcat on Amazon EC2 instance.
I have heard that EC2 is ephemeral and anything we put in may not survive restarts. So if I add a Tomcat in EC2 and restart the instance will it be deleted or removed.
What are the ways to overcome this issue ?
Sorry I am a newbie in AWS.
If what you need is just Tomcat then you can use pre-configured Amazon Beanstalk Tomcat container which does exactly that.
However if you need to build custom EC2 you can install tomcat on EBS linked to EC2, or even better use Amazon EFS to share between multiple EC2.
Ephemeral disk is temporary storage that it is added to your instance and sized according to instance type. The larger the instance, the more temporary storage.
For some instances like c1.medium and m1.small they use instance storage automatically as SWAP as they have a limited amount of memory, while many others are automatically formatted and mounted at /mnt.
You can take snapshots of your EC2 instances while they are running. Snapshots allow you to create AMI's from your current machine state, which will contain everything in your ephemeral storage. When you launch a new instance based on that AMI, it will contain everything as it was in the snapshot.
An Amazon Machine Image (AMI) provides the information required to launch an instance.
Take note that there is a big difference between stop and terminate. If you stop an instance that is backed by EBS, the information on the root volume will still be in the same state when you start the machine again. If you terminate the machine without taking a snapshot, even if it is backed by EBS, the storage inside the ephemeral disk will be lost forever.
All AMIs are categorized as either backed by Amazon EBS or backed by instance store. The former means that the root device for an instance launched from the AMI is an Amazon EBS volume created from an Amazon EBS snapshot. The latter means that the root device for an instance launched from the AMI is an instance store volume created from a template stored in Amazon S3. For more information, see Amazon EC2 Root Device Volume.
The above answers should provide a good idea about what you can and cannot do with ephemeral disks, but I advise all (myself included) to learn more about ephemeral disks and their primary use cases.
Here are some good use cases for ephemeral storage that I know of:
Temporary backup
Re-format the original instance storage and use part of it for SWAP
RAID 10 with 6 disks (4 EBS and 2 Ephemeral disks) to improve overall performance and provide HA
Application cache, logs, any other random data
You are save as long as you not store it on ephemeral partition which is a part of your instance check this to have more info
http://www.heitorlessa.com/working-with-amazon-aws-ec2-ephemeral-disks/
basically you need to mount elastic drive to your instance and install Tomcat and all your software there, ephemeral storage is for swap or caching
You only need storage to keep your information, EBS or S3. EC2 instances are virtual machines and will not lose your information if restarts with storage.
Get all information you need at https://aws.amazon.com/es/ec2/
I have an Amazon EC2 instance with AutoScaling and Load balancer.
I deployed an application and configured Apache.
Everything went fine but Amazon for some reason terminated my instance and started a new one. I lost all the code and configuration there?
What should I do?
Maybe attach a EBS volume and deploy everything there? But my Apache server is installed on the main volume.
Can anyone help me?
If you are using autoscaling, instances will be terminated if they become unhealthy. In order to use autoscaling effectively, you should not keep any persistant data on the instance itself. This is called Shared Nothing architecture.
What you want to do, is create an AMI that has all your application and or tools to bootstrap your application. You would use this AMI as part of the launch configuration for your autoscale group. So if a new instance gets launched, either due to failure or needing to scale, your application will be back up without any interaction from you.