I have a use case to maintain 2 servers, primary and secondary. Use secondary if the primary fails/stops. Only one server can be used at a time. The primary has a lot of activity going on with it, like installation and multiple read-writes. In order to replicate this to the secondary I'll have to create timely snapshots and then restore them when required. In order to skip this, can't I use a shared volume for both the servers, so that I can use the secondary without first having to restore a snapshot from the primary server? I've read about EBS volume type, io2 which supports multi-attach wherein as the name suggests can be attached to multiple instances and used as shared volume, which can't be done with other volume types. Will this create some kind of issue like data corruption if used as root volume. Don't want to use NFS/EFS as it is not compatible with the application I use.
This is AWS specific
You can use an EBS volume for your multi-attach app data needs.
One of the reasons you can’t multi-attach a root volume is that these root volumes are disposed of when an EC2 instance is terminated. AWS recommends that app data is not stored on the root volume due to the ephemeral nature of the root volumes.
AWS documentation for root volumes can be found here https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/RootDeviceStorage.html
I recommend mounting a second volume for your app data.
Related
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 EC2 instance with EBS volumes A and B attached to it, and I want to copy/replicate/sync the data from a specific folder in EBS A to EBS B.
EBS A is the primary volume which hosts application installation data and user data, and I'm looking to effectively backup the user data (which is just a specific directory) to EBS B in the event that the application install gets corrupted or needs to be blown away. That way I can simply stand up a new EC2 with a new primary EBS, call it C, attach EBS B to it, and push the user data from EBS B into EBS C.
I am using Amazon Linux 2 and have already gone through the process of formatting and mounting the backup EBS. I can manually copy data from EBS A to EBS B but I was hoping someone could point me towards a best practices for keeping the directory data in sync between the two volumes?
I have found recommendations for rsync, a cron task, and gluster for similar use cases. Would is be considered good practice to use one these for my use case?
While you can use rsync, a better alternative is Data Lifecycle Manager, which will make automated EBS snapshots.
The reason that it's better is that you can specify a fixed number of snapshots, at a fixed time interval, so you don't need to restore the latest (important if the "current" data is corrupted).
To use this most effectively, I would separate the boot volume from the application/data volume(s). So you could just restore the snapshot, spin up a new instance, and mount the restored volume to it.
How can i attach persistent storage on Elastic Beanstalk ?
I know i need to have a .config file where i set the parameters of the environment to run every time an instance is created.
My goal is to have a volume, let's say 100GB, that even if the instances got deleted/terminated, i have this volume with persistent data where all instances can access to read from.
I could use S3 to store this data, but it would require changes to the application, and latency could be a problem.
This way i could access the filesystem like any common server.
AWS now offer a solution called Elastic File System (Amazon EFS) that lets multiple instances access a shared file store.
If your desire is to have a central data repository that all EC2 instances can access, then Amazon S3 would be your best option.
Normal disk volumes are provided via Elastic Block Store (EBS). EBS volumes can only be mounted to one EC2 instance at a time. Therefore, to share data that is contained on an EBS volume, you will need to use normal network sharing methods to mount network volumes.
However, if your goal is to provide shared access without one specific instance sharing a volume to other instances, then it is better to use S3 because it is accessible from all instances. It would likely be worth the effort of modifying your application to take advantage of S3.
I am facing an architecture-related problem:
I have created a new environment in ElasticBeanstalk and pushed my app there. All good so far. I have set it to auto scale up/down.
My app depends on filesystem storage (it creates files and then serves them to users). I am using an EBS volume (5gb large) to create the files and then push them to S3 and delete them from EBS. The reason I'm using EBS is because of ephemeral filesystem in EC2 instances.
When AWS scales up new instances don't have the EBS volume attached because EBS can be attached to one instance at a time.
When it scales down, it shuts down the instance that had the EBS volume attached, which totally messes things up.
I have added to /etc/fstab a special line that will automatically mount the EBS volume to /data but that only applies for the instance I add the file to /etc/fstab. I guess the solution here would be to create a customized AMI image with that special line. But again, EBS can't be attached to more than one instance at a time, so it seems like a dead end.
What am I thinking wrong? What would be a possible solution or the proper way of doing it?
For some reason, I believe that using S3 is not the right way of doing it.
S3 is a fine way to do it: your application creates the file, uploads to S3, removes the file from the local filesystem, and hands a URL to access the file back to the client. Totally reasonable. Why you can't use ephemeral storage for this. Instance store-backed instances have additional storage available, mounted to /mnt by default. Why can't the application create the file there? If the files don't need to be persisted between instance start/stop/reboot then there's no great reason to use EBS (unless you want faster boot times for your autoscale instances I suppose).
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