Learning Migrating EC2 Resources

Get ready to learn about Migrating EC2 resources with features – SSH Keys and Security Groups.

EC2 is a web service
EC2 provides resizable compute capacity
Migrating an instance involves
- copying the data and images
- check for security groups and SSH keys
- then restarting fresh instances.

SSH Keys

AWS does not keep any SSH private keys after they are generated
public keys are made available to EC2 instances when they are running
retrieve a fingerprint of each key from API, SDK, CLI or the AWS Management Console.
SSH public keys are stored in a region only.
AWS does not copy or synchronize configured SSH keys between regions.
can log in to an existing Linux instance in the source region, obtain a copy of the public key (from
~/.ssh/authorized_keys), and import this public key into the target region.
Auto Scaling launch configurations and CloudFormation templates might refer to SSH keys using the key pair name.

Key pairs in the AWS Management Console

Security Groups

restrict ingress traffic (or in VPC, ingress and egress traffic) to a group of EC2 instances.
security group’s rule can access source (or in VPC, destination) by
- CIDR notation in IPv4 address range as – a.b.c.d/x
- security group identifier as – XXXXXXXX
The scope of every security group is the region.
The same name can exist in multiple regions but have different definitions of what traffic is
permitted to pass.
All instances which are activated, should be a member of the security group.
review configured security groups to ensure that the required level of network access restrictions is in place.
To export a copy of the definitions of existing security groups (using the command line tools), run the following command: ec2-describe-group –H -–region <sourceregionname> > security_groups.txt

Amazon Machine Images

It is a special type of preconfigured operating system image
used to create a virtual machine (an EC2 instance) within the EC2 environment.
AMI is assigned an identifier, of form “ami-XXXXXXXX”, where ”X” is a hexadecimal value (0-9, A-F).
Each AMI is unique per region.
AMIs do not span multiple regions.
the same content of an AMI can be available in other regions
A unique AMI ID is given to every region’s copy of data
User can create their own AMIs from instances which are running
AMI Copy function is used to migrate AMIs across regions and can be executed by
- AWS Management Console
- Amazon EC2 CLI
- Amazon EC2 API
AMI Copy is available for AMIs backed by EBS and instance store-backed AMIs.
Every AMI copy has a unique AMI ID
Changes done to source AMI are not done to new AMI during AMI copy process
You must recopy the AMI to the target regions to copy the changes made to the source AMI.

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