For any number of instances prepared as discussed earlier, what can we do with Systems Manager? One of the first things that we can do is that we can take a look at our fleet. You can go to the Systems Manager console and under the node management section, you will see the Fleet Manager feature. All of your managed instances will be displayed in this console. Fleet Manager will give you visibility into the details of each managed instance.

Another action that we can take is that we can connect to any of the instances securely using the Session Manager feature. Under the node management section of systems manager, you will notice the Session Manager feature. The Session Manager is a fully managed capability that lets you connect to any managed instance, using an interactive browser shell as a login. It requires no open inbound ports and no need to manage bastion host or SSH keys for connectivity to your instances. Communication between Session Manager and the instances is secure and Session Manager tracks all commands and output produced in a session for auditing and compliance reasons.

The third item that we can do is that we can also execute one or more commands on any of the instances or all of them, if we desire. The Systems Manager Run Command will permit you to execute a command on one or more of your managed instances. The complexity of the command to be executed is defined on the command document as discussed earlier. Documents define the actions that the agent performs on your instances on our shared resources in the Systems Manager console.

In general, the Run Command will require that you specify a document and specify the target instances where the document is to be executed. For any particular instance, you see a status as well as the output of a command on that instance. Like most features that caused a change in your instances the Run Command can define a rate control or what percentage of your fleet is updated at the same time, using a value or a percentage for concurrency and under what error thresholds should the command stop executing altogether in order to investigate any issues that have been observed.

We can separate configuration data from code with systems manager Parameter Store. Parameter Store provides a centralized storage to manage your configuration in plain text data such as database connections or license codes and strings or secrets such as passwords or any other application configuration data. Parameter Store is integrated with AWS Key Management Service or KMS.

For you to be able to automatically encrypt parameter values if needed, you can track parameter changes by using versions, create parameter change notifications and your own custom validation routines using AWS Lambda functions, Parameter stored data accessibility is not limited to AWS Systems Manager. Parameters can be referenced by other AWS services such as Amazon ECS, AWS Lambda, CloudFormation, CodeDeploy, CodePipeline, and your own custom applications.

The Maintenance Window feature of Systems Manager is the next item that we will review. With Maintenance Windows you can run potentially disruptive pass manually or during a predefined time. A Maintenance Window gives you the ability to schedule tasks such as patching an operating system, updating drivers, or installing software and managed instances. You can set limits for simultaneous executions and allowable error rates.

The Maintenance Window is an independent resource that allows you to define and run complex tasks using a Run Command document, and AWS step function, or an AWS Lambda function. You can also view a history of all tasks executed in a Maintenance Window if you desire. Once a Maintenance Window is created, you can register targets to it by name, which assigns a set of instances to your Maintenance Window. You specify instance tags, choose a resource group, or choose instances manually. Maintenance Windows can run any number of tasks on your managed instances, avoiding operational downtime so that you can run administration tasks that are potentially disruptive during a predefined period where changes can be applied with little to no impact to the availability of your application.