It is important to have a fault tolerance system in place. This helps you to keep your infrastructure function normally even if there is a system failure or breakdown. AWS EC2 is a service which is extensively used by almost all cloud-native organizations. Following certain practices related to EC2 instances and AMIs will ensure high availability of your cloud infrastructure.
What is AWS EC2 instance AMI?
AMI stands for Amazon Machine Image. This is basically a master image that provides the required information to launch an instance and the configuration required to launch an Amazon EC2 instance. AMI contains a template for the root volume which primarily consists of an operating system, application server. It also allows users to select launch permissions and a block device which maps the storage of the launched instance. Users can use a single AMI for a single instance. Multiple instances can also be launched with a single AMI of the users want the same configuration for multiple instances. Different AMIs can also be used for different individual instances according to the requirement.
Know how old are your AWS EC2 instance AMIs
It is important to take note of the age of your AMI associated with AWS EC2 instances. It is recommended to use up to date AMIs. Up-to-date AMI takes care of the reliability of your EC2 deployments and also ensures effective scaling. These AMIs can help you recover from the latest checkpoint in case of any failure or outage.
Centilytics provides a useful insight on EC2 AMI age of your instances and tells the corresponding age of your AWS EC2 instance AMI.
Insight Descriptions:
There can be 3 possible scenarios:
| Severity | Description |
 OK |
This indication will be displayed when the corresponding EC2 AMI age is below 30 days. |
 WARNING |
This indication will be displayed when the corresponding EC2 AMI age is between 30 to 90 days. |
 CRITICAL |
This indication will be displayed when the corresponding EC2 AMI age is more than 90 days. |
Description of further columns are as follows:
- Account Id: This column shows the respective account ID of the user’s account.
- Account Name: This column shows the corresponding account name to the user’s account.
- Region: This column shows the region in which the resource exists.
- Identifier: This column shows the unique AMI id to uniquely identify different AMIs in your AWS account.
- Image Name: This column shows the name of the AMI image
- Creation date: This column shows the date on which the AMI was created.
- Age of Image (days): This column shows the age of your EC2 instance AMI.
Filters applicable:
| Filter Name | Description |
| Account Id | Applying the account Id filter will display data for the selected account Id. |
| Region | Applying the region filter will display data corresponding to the selected region |
| Severity | Applying severity filter will display public snapshots according to the selected severity type i.e. selecting critical will display all resources with critical severity. Same will be the case for Warning and Ok severity types. |
| Resource Tags | Applying resource tags filter will display those resources which have been assigned the selected resource tag. For e.g., A user has tagged some public snapshots by a resource tag named environment. Then selecting an environment from the resource tags filter will display all those resources tagged by the tag name environment. |
| Resource Tags Value | Applying resource tags value filter will display data which will have the selected resource tag value. For e.g. – Let’s say a user has tagged some resource by a tag named environment and has a value say production (environment: production). Hence, the user can view data of all the resources which have “environment:production” tag assigned. The user can use the tag value filter only when a tag name has been provided. |
You can also read about Amazon EC2 auto-scaling groups and its configuration.