I have two amazon machine instances running.Both of them are m3.xlarge instances. One of them has the right software and configuration that I want to use.I want to create a snapshot of the EBS volume for that machine and use that as the EBS volue to boot the second machine from. Can I do that and expect it to work without shutting down the first machine.
It is well described in the AWS documentation...
"You can take a snapshot of an attached volume that is in use. However, snapshots only capture data that has been written to your Amazon EBS volume at the time the snapshot command is issued. This might exclude any data that has been cached by any applications or the operating system. If you can pause any file writes to the volume long enough to take a snapshot, your snapshot should be complete. However, if you can't pause all file writes to the volume, you should unmount the volume from within the instance, issue the snapshot command, and then remount the volume to ensure a consistent and complete snapshot.
I have amazon as well, with 3 different clusters. With one of my clusters after setting up 25 of them I realized there was a small issue in the configuration and had live traffic going to them so I couldn't' shut down.
You can snapshot the first machines volume while it's still running, I had to do this myself. It took a little while, but ultimately it worked out. Please note that amazon cannot guarantee the consistency of the disk when doing this.
I did a snapshot of the entire thing, fixed what needed to be fixed, and spooled up 25 new servers and terminated the other 25 ( easier than modifying volumes, etc ).. But you can create a new volume with the new snapshot, and attach it to an instance and do what needs to be done to get it to boot off that volume without much of a headache.
Being that I went the easy route of spooling up new instances after my snapshot was complete, I can't walk you through on how to get a running instance to boot off a new volume.
Related
If you take an AMI from an EC2, and the AMI takes, say, 1 hour to be available; and you choose the option not to skip the reboot.
All the files in the AMI will:
a) reflect their exact condition from the time the EC2 was rebooted? or
b) they may reflect any condition in this 1 hour interval which is what it took for the AMI to be available.
I always considered option a, but I'm not so sure any more, specially after I noticed that when you take an AMI in the console, it gives this message:
"Currently creating AMI ..... Check that the AMI status is 'Available' before deleting the instance or carrying out other actions related to this AMI."
I want to know if it's safe to start applying changes in an EC2 instance after an AMI is requested and the EC2 rebooted, but before the AMI is available.
An Amazon Machine Image (AMI) will contain a copy of the disk at it was at exactly at the point in time when the API call was issued.
Or, if the instance is rebooted as part of the image creation, it will contain a copy of the disk as it was between the time when the operating system shutdown and when the operating system started again.
The time taken for an AMI to become available involves copying disk blocks to the Snapshot used by the AMI. Any disk changes during that time will not be reflected in the AMI. This is possible because the disk is virtual. (It's a bit like a database being able to roll-back due to the use of log files.)
From Create Amazon EBS snapshots - Amazon Elastic Compute Cloud:
Snapshots occur asynchronously; the point-in-time snapshot is created immediately, but the status of the snapshot is pending until the snapshot is complete (when all of the modified blocks have been transferred to Amazon S3), which can take several hours for large initial snapshots or subsequent snapshots where many blocks have changed. While it is completing, an in-progress snapshot is not affected by ongoing reads and writes to the volume... snapshots only capture data that has been written to your Amazon EBS volume at the time the snapshot command is issued.
I wanted to know is it possible to automate the creation of AMI in AWS without downtime and data loss, if possible how can we achieve it.
I have use system manager-> maintenance window in which i have set the reboot to true for data integrity, but i need a way so that the data is not lost.
Any help will be appreciated.
Thank-you.
Answering it as per comments discussion, question is somehow still vague to me
You have EBS right now. I'm not sure if your Instances are in Same AZ or not. If they are in same AZ then you can use EBS multi attach feature (available for IO volumes only) to share same storage with all of them.
Regarding backup you can choose EBS snapshots
Ideally my suggestion to you would be create a launch template, use EFS that can be mounted to multiple instances in same region, if you want it across regions then create mount targets. EFS is natively integrated with AWS backup.
Whenever any failover happens or your EC2 crashes for any reason and it goes less than your target capacity, auto scaling would automatically provision a new instance using launch template which would be using same EFS
but i need a way so that the data is not lost.
if you want to achieve this, then According to Docs, you need to ensure that application or os is not writing to ebs, which can be managed by either a script or a custom logic.
You can take a snapshot of an attached volume that is in use. However, snapshots only capture data that has been written to your Amazon EBS volume at the time the snapshot command is issued. This might exclude any data that has been cached by any applications or the operating system. If you can pause any file writes to the volume long enough to take a snapshot, your snapshot should be complete. However, if you can't pause all file writes to the volume, you should unmount the volume from within the instance, issue the snapshot command, and then remount the volume to ensure a consistent and complete snapshot.
if you achieved the above then you can automate the creation, retention, and deletion of EBS snapshots and EBS-backed AMIs it using Data Lifecycle Manager
I haven't tried this but I think exporting VM to S3 and then automating the entire pipeline with Ec2 image builder should do the trick, you can customise your further images with build components
Refers importing and exporting vm's
Unfortunately there is not of box solution other than compromising data integrity but you can try above mentioned which can ensure data integrity and automation
I have an AWS EC2 Windows Server 2012 R2 instance with a magnetic EBS-volume D:\ (Windows SO is on C:\).
My server works on D:\ writes everytime some temporally files in D:\temp (session file, cache etc.) and reads some static files in D:\htdocs.
I need do a daily consistent snapshot of EBS-volume without downtime
About this question a lot of people says:
Snapshot EBS if the volume is in use it is possible but not recommended
From official documentation:
You can take a snapshot of an attached volume that is in use. However, snapshots only capture data that has been written to your Amazon EBS volume at the time the snapshot command is issued. If you can pause any file writes to the volume long enough to take a snapshot, your snapshot should be complete.
and here:
EBS volumes and snapshots operate at a block level - a consequence of
which allows snapshots to be taken while an instance is running, even
if the EBS volume is in use. However, only data that is actually on
the disk (i.e. not in a file cache) will be included in the snapshot.
It is the latter reason that gives rise to the idea of consistent
snapshots.
The recommended way is to detach the volume, snapshot it, and reattach it
My question is:
if the snapshot is inconsistent because when i do it there are writing operations, can i remount it? Since only files written is temporally files but they aren't important for me, if are damaged can i simple delete them (after i remount snapshot)? my only target it's to be safe the static file.
If you create a snapshot, you will be able to create a volume from it, and remount it without any issues.
HOWEVER: you are not guaranteed that the data in the volume is consistent.
Consider this scenario: you commit a 1 MB file to an SSD-backed EBS volume. This will require 4 x 256k IO operations. So the first 3 complete, then you take your snapshot, then the 4th block is written.
You will be able to create a volume from your snapshot, but your file will only be 768k in size - the final block will not be there, since it was written after the snapshot was created.
If you have control over what is writing to the disk, pausing it and flushing any caches is really the only way to ensure that the data on the resulting snapshot is consistent.
I have just launched the micro instance with Centos AMI image. I have heard that if i stop the instance then my chnages will be lost. So i have read that if i use EBS then chnages will be saved.
But Its not clear to me how to do that. I want that if i stop or restart the machine then my chnages are still there.
DO i need to chnage my hard drive to EBS. How can i do that
My Root Device is comming as EBS with 10GB EBS volume. Is that ok
Yes, the micro instances always use EBS root, so you don't have to do anything special.
If you 'stop' your instance, and later start, it's moving your hard drive to another computer and rebooting.
If you terminate your instance, your EBS drive will be fine as long as "delete EBS drive on termination" is not set on your drive.
When you use other instances, you'll have to verify the AMI type. Not all AMIs are available in all combinations:
EBS vs ephemeral
64 bit vs 32bit
PVM vs HVM (Everything is PVM except the really high-end Compute Cluster)
When you first get started in the cloud, EBS is a big deal. But as you get to be a cloud expert, you'll prefer non-EBS instances. EBS will only be used on a few servers, like your database or your syslog server. Most of your app should be stateless. Your app servers should only store their data in the database, and only write their logs to a central logging server, and only get their code from github or a package repository. So so there is no need to 'backup' your app server boxes, since they can be re-created at any time from external sources using something like Puppet or Chef.
Only your 'stateful' boxes like databases need backing up, and EBS helps there.
I am trying to create a backup mechanism for our server, so that if my system crashes, I should be able to create the whole system by running a single script
After going through Amazon documentation, this is my understanding of creating a backup and restoring
Backup
Create a AMI Image (this can be updated monthly)
Create a snapshot (This can be done using a daily script creating a snapshot)
Restore (A script to)
Create an EBS instance using AMI
Attach the EBS volume to Instance created
Now my Questions are
Is it the best way to take a backup and restore?
Do we actually need to backup 2 things, AMI and EBS volume (using snapshot), Can we just keep snapshots?
I understand this cannot work for a local instance store instance, as there is no snapshot functionality. So how can I create a backup and restore process for local instance store instances?
As I could not find any better alternative, I am sticking with the initial approach.
For EBS
Backup:
Create a AMI Image (this can be updated monthly).
Create a snapshot (This can be done using a daily script creating a snapshot).
Restore (A script to)
Create an EBS instance using AMI.
Attach the EBS volume to Instance created.
For instance store, I am only keeping the application (no database), so no need to keep a backup of that.
EBS Snapshots are an excellent way to create backups.
You can perform frequent Snapshots of your EBS Volumes via scripts. Weekly, Daily, Hourly, or as frequently as your Credit Card will allow. The only limit is around how many simultaneous snapshots you can be doing - when you hit that, the EBS API will start giving back errors until a few of the in-flight operations complete.
Snapshots can also be copied from Region to Region in order to provide backup against a catastrophic event.
When you snapshot an EBS volume, that snapshot is of the entire volume. Even if it was created from an AMI, your snapshot contains everything you need to create a new instance of the volume. You can pretty easily try this yourself.
If your instances are Linux based, there is no need to create an AMI if you're taking snapshots. You can create the AMI on the fly, from the snapshots, when you need to recover. If you got that process automated, it's pretty easy to do.
In Windows there is a limitation not allowing to launch an EC2 instance from a snapshot, so AMIs must be used. There are ways to workaround that limitation: You can check out the this post I wrote in our company's blog:
http://www.n2ws.com/blog/3-ways-ec2-windows-backup-and-recovery.html
I would suggest to use Auto Scaling in addition to EBS snapshots. If Instance is dying because of Hardware failure or it's scheduled for retirement by Amazon, Auto Scaling will start new Instance automatically.
But in this case, you have to setup NAS for your dynamic data. Depending on Server Load, the number of running Instances will be different and all your scaling servers must mount NAS storage which is shared across them.
Your Database should be on separate server or servers as well. Or you might want to use Amazon RDS as it has great auto-backup / Point-In-Time-Restore features, but you have to pay extra for that.
1) Yes.Snapshot is best way to backup and restore EBS volumes.
2) Depends, if you have the root volume as EBS backed AMI, then you can snapshot them as well and improves the manageability
3) Rsync and AMI is the option available for instance store