# Managing Amazon EC2 Instances
<a name="examples-ec2-instances"></a>

## Prerequisites
<a name="codeExamplePrereq"></a>

Before you begin, we recommend you read [Getting started using the AWS SDK for C\$1\$1](getting-started.md). 

Download the example code and build the solution as described in [Getting started on code examples](getting-started-code-examples.md). 

To run the examples, the user profile your code uses to make the requests must have proper permissions in AWS (for the service and the action). For more information, see [Providing AWS credentials](credentials.md).

## Create an Instance
<a name="create-an-instance"></a>

Create a new Amazon EC2 instance by calling the EC2Client’s `RunInstances` function, providing it with a [RunInstancesRequest](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-ec2/html/class_aws_1_1_e_c2_1_1_model_1_1_run_instances_request.html) containing the [Amazon Machine Image (AMI)](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AMIs.html) to use and an [instance type](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.html).

 **Includes** 

```
#include <aws/core/Aws.h>
#include <aws/ec2/EC2Client.h>
#include <aws/ec2/model/RunInstancesRequest.h>
#include <iostream>
```

 **Code** 

```
    Aws::EC2::EC2Client ec2Client(clientConfiguration);

    Aws::EC2::Model::RunInstancesRequest runRequest;
    runRequest.SetImageId(amiId);
    runRequest.SetInstanceType(Aws::EC2::Model::InstanceType::t1_micro);
    runRequest.SetMinCount(1);
    runRequest.SetMaxCount(1);

    Aws::EC2::Model::RunInstancesOutcome runOutcome = ec2Client.RunInstances(
            runRequest);
    if (!runOutcome.IsSuccess()) {
        std::cerr << "Failed to launch EC2 instance " << instanceName <<
                  " based on ami " << amiId << ":" <<
                  runOutcome.GetError().GetMessage() << std::endl;
        return false;
    }

    const Aws::Vector<Aws::EC2::Model::Instance> &instances = runOutcome.GetResult().GetInstances();
    if (instances.empty()) {
        std::cerr << "Failed to launch EC2 instance " << instanceName <<
                  " based on ami " << amiId << ":" <<
                  runOutcome.GetError().GetMessage() << std::endl;
        return false;
    }
```

See the [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/ec2/run_instances.cpp).

## Start an Instance
<a name="start-an-instance"></a>

To start an Amazon EC2 instance, call the EC2Client’s `StartInstances` function, providing it with a [StartInstancesRequest](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-ec2/html/class_aws_1_1_e_c2_1_1_model_1_1_start_instances_request.html) containing the ID of the instance to start.

 **Includes** 

```
#include <aws/ec2/EC2Client.h>
#include <aws/ec2/model/StartInstancesRequest.h>
```

 **Code** 

```
    Aws::EC2::EC2Client ec2Client(clientConfiguration);

    Aws::EC2::Model::StartInstancesRequest startRequest;
    startRequest.AddInstanceIds(instanceId);
    startRequest.SetDryRun(true);

    Aws::EC2::Model::StartInstancesOutcome dryRunOutcome = ec2Client.StartInstances(startRequest);
    if (dryRunOutcome.IsSuccess()) {
        std::cerr
                << "Failed dry run to start instance. A dry run should trigger an error."
                << std::endl;
        return false;
    } else if (dryRunOutcome.GetError().GetErrorType() !=
               Aws::EC2::EC2Errors::DRY_RUN_OPERATION) {
        std::cout << "Failed dry run to start instance " << instanceId << ": "
                  << dryRunOutcome.GetError().GetMessage() << std::endl;
        return false;
    }

    startRequest.SetDryRun(false);
    Aws::EC2::Model::StartInstancesOutcome startInstancesOutcome = ec2Client.StartInstances(startRequest);

    if (!startInstancesOutcome.IsSuccess()) {
        std::cout << "Failed to start instance " << instanceId << ": " <<
                  startInstancesOutcome.GetError().GetMessage() << std::endl;
    } else {
        std::cout << "Successfully started instance " << instanceId <<
                  std::endl;
    }
```

See the [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/ec2/start_stop_instance.cpp).

## Stop an Instance
<a name="stop-an-instance"></a>

To stop an Amazon EC2 instance, call the EC2Client’s `StopInstances` function, providing it with a [StopInstancesRequest](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-ec2/html/class_aws_1_1_e_c2_1_1_model_1_1_stop_instances_request.html) containing the ID of the instance to stop.

 **Includes** 

```
#include <aws/ec2/model/StopInstancesRequest.h>
```

 **Code** 

```
    Aws::EC2::EC2Client ec2Client(clientConfiguration);
    Aws::EC2::Model::StopInstancesRequest request;
    request.AddInstanceIds(instanceId);
    request.SetDryRun(true);

    Aws::EC2::Model::StopInstancesOutcome dryRunOutcome = ec2Client.StopInstances(request);
    if (dryRunOutcome.IsSuccess()) {
        std::cerr
                << "Failed dry run to stop instance. A dry run should trigger an error."
                << std::endl;
        return false;
    } else if (dryRunOutcome.GetError().GetErrorType() !=
               Aws::EC2::EC2Errors::DRY_RUN_OPERATION) {
        std::cout << "Failed dry run to stop instance " << instanceId << ": "
                  << dryRunOutcome.GetError().GetMessage() << std::endl;
        return false;
    }

    request.SetDryRun(false);
    Aws::EC2::Model::StopInstancesOutcome outcome = ec2Client.StopInstances(request);
    if (!outcome.IsSuccess()) {
        std::cout << "Failed to stop instance " << instanceId << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    } else {
        std::cout << "Successfully stopped instance " << instanceId <<
                  std::endl;
    }
```

See the [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/ec2/start_stop_instance.cpp).

## Reboot an Instance
<a name="reboot-an-instance"></a>

To reboot an Amazon EC2 instance, call the EC2Client’s `RebootInstances` function, providing it with a [RebootInstancesRequest](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-ec2/html/class_aws_1_1_e_c2_1_1_model_1_1_reboot_instances_request.html) containing the ID of the instance to reboot.

 **Includes** 

```
#include <aws/ec2/EC2Client.h>
#include <aws/ec2/model/RebootInstancesRequest.h>
#include <iostream>
```

 **Code** 

```
    Aws::EC2::EC2Client ec2Client(clientConfiguration);

    Aws::EC2::Model::RebootInstancesRequest request;
    request.AddInstanceIds(instanceId);
    request.SetDryRun(true);

    Aws::EC2::Model::RebootInstancesOutcome dry_run_outcome = ec2Client.RebootInstances(request);
    if (dry_run_outcome.IsSuccess()) {
        std::cerr
                << "Failed dry run to reboot on instance. A dry run should trigger an error."
                <<
                std::endl;
        return false;
    } else if (dry_run_outcome.GetError().GetErrorType()
               != Aws::EC2::EC2Errors::DRY_RUN_OPERATION) {
        std::cout << "Failed dry run to reboot instance " << instanceId << ": "
                  << dry_run_outcome.GetError().GetMessage() << std::endl;
        return false;
    }

    request.SetDryRun(false);
    Aws::EC2::Model::RebootInstancesOutcome outcome = ec2Client.RebootInstances(request);
    if (!outcome.IsSuccess()) {
        std::cout << "Failed to reboot instance " << instanceId << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    } else {
        std::cout << "Successfully rebooted instance " << instanceId <<
                  std::endl;
    }
```

See the [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/ec2/reboot_instance.cpp).

## Describe Instances
<a name="describe-instances"></a>

To list your instances, create a [DescribeInstancesRequest](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-ec2/html/class_aws_1_1_e_c2_1_1_model_1_1_describe_instances_request.html) and call the EC2Client’s `DescribeInstances` function. It will return a [DescribeInstancesResponse](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-ec2/html/class_aws_1_1_e_c2_1_1_model_1_1_describe_instances_response.html) object that you can use to list the Amazon EC2 instances for your AWS account and AWS Region.

Instances are grouped by *reservation*. Each reservation corresponds to the call to `StartInstances` that launched the instance. To list your instances, you must first call the `DescribeInstancesResponse` class’ `GetReservations` function, and then call `getInstances` on each returned Reservation object.

 **Includes** 

```
#include <aws/ec2/EC2Client.h>
#include <aws/ec2/model/DescribeInstancesRequest.h>
#include <aws/ec2/model/DescribeInstancesResponse.h>
#include <iomanip>
#include <iostream>
```

 **Code** 

```
    Aws::EC2::EC2Client ec2Client(clientConfiguration);
    Aws::EC2::Model::DescribeInstancesRequest request;
    bool header = false;
    bool done = false;
    while (!done) {
        Aws::EC2::Model::DescribeInstancesOutcome outcome = ec2Client.DescribeInstances(request);
        if (outcome.IsSuccess()) {
            if (!header) {
                std::cout << std::left <<
                          std::setw(48) << "Name" <<
                          std::setw(20) << "ID" <<
                          std::setw(25) << "Ami" <<
                          std::setw(15) << "Type" <<
                          std::setw(15) << "State" <<
                          std::setw(15) << "Monitoring" << std::endl;
                header = true;
            }

            const std::vector<Aws::EC2::Model::Reservation> &reservations =
                    outcome.GetResult().GetReservations();

            for (const auto &reservation: reservations) {
                const std::vector<Aws::EC2::Model::Instance> &instances =
                        reservation.GetInstances();
                for (const auto &instance: instances) {
                    Aws::String instanceStateString =
                            Aws::EC2::Model::InstanceStateNameMapper::GetNameForInstanceStateName(
                                    instance.GetState().GetName());

                    Aws::String typeString =
                            Aws::EC2::Model::InstanceTypeMapper::GetNameForInstanceType(
                                    instance.GetInstanceType());

                    Aws::String monitorString =
                            Aws::EC2::Model::MonitoringStateMapper::GetNameForMonitoringState(
                                    instance.GetMonitoring().GetState());
                    Aws::String name = "Unknown";

                    const std::vector<Aws::EC2::Model::Tag> &tags = instance.GetTags();
                    auto nameIter = std::find_if(tags.cbegin(), tags.cend(),
                                                 [](const Aws::EC2::Model::Tag &tag) {
                                                     return tag.GetKey() == "Name";
                                                 });
                    if (nameIter != tags.cend()) {
                        name = nameIter->GetValue();
                    }
                    std::cout <<
                              std::setw(48) << name <<
                              std::setw(20) << instance.GetInstanceId() <<
                              std::setw(25) << instance.GetImageId() <<
                              std::setw(15) << typeString <<
                              std::setw(15) << instanceStateString <<
                              std::setw(15) << monitorString << std::endl;
                }
            }

            if (!outcome.GetResult().GetNextToken().empty()) {
                request.SetNextToken(outcome.GetResult().GetNextToken());
            } else {
                done = true;
            }
        } else {
            std::cerr << "Failed to describe EC2 instances:" <<
                      outcome.GetError().GetMessage() << std::endl;
            return false;
        }
    }
```

Results are paged; you can get further results by passing the value returned from the result object’s `GetNextToken` function to your original request object’s `SetNextToken` function, then using the same request object in your next call to `DescribeInstances`.

See the [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/ec2/describe_instances.cpp).

## Enable Instance Monitoring
<a name="enable-instance-monitoring"></a>

You can monitor various aspects of your Amazon EC2 instances, such as CPU and network utilization, available memory, and disk space remaining. To learn more about instance monitoring, see [Monitoring Amazon EC2](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/monitoring_ec2.html) in the Amazon EC2 User Guide.

To start monitoring an instance, you must create a [MonitorInstancesRequest](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-ec2/html/class_aws_1_1_e_c2_1_1_model_1_1_monitor_instances_request.html) with the ID of the instance to monitor, and pass it to the EC2Client’s `MonitorInstances` function.

 **Includes** 

```
#include <aws/ec2/EC2Client.h>
#include <aws/ec2/model/MonitorInstancesRequest.h>
#include <aws/ec2/model/UnmonitorInstancesRequest.h>
#include <iostream>
```

 **Code** 

```
    Aws::EC2::EC2Client ec2Client(clientConfiguration);
    Aws::EC2::Model::MonitorInstancesRequest request;
    request.AddInstanceIds(instanceId);
    request.SetDryRun(true);

    Aws::EC2::Model::MonitorInstancesOutcome dryRunOutcome = ec2Client.MonitorInstances(request);
    if (dryRunOutcome.IsSuccess()) {
        std::cerr
                << "Failed dry run to enable monitoring on instance. A dry run should trigger an error."
                <<
                std::endl;
        return false;
    } else if (dryRunOutcome.GetError().GetErrorType()
               != Aws::EC2::EC2Errors::DRY_RUN_OPERATION) {
        std::cerr << "Failed dry run to enable monitoring on instance " <<
                  instanceId << ": " << dryRunOutcome.GetError().GetMessage() <<
                  std::endl;
        return false;
    }

    request.SetDryRun(false);
    Aws::EC2::Model::MonitorInstancesOutcome monitorInstancesOutcome = ec2Client.MonitorInstances(request);
    if (!monitorInstancesOutcome.IsSuccess()) {
        std::cerr << "Failed to enable monitoring on instance " <<
                  instanceId << ": " <<
                  monitorInstancesOutcome.GetError().GetMessage() << std::endl;
    } else {
        std::cout << "Successfully enabled monitoring on instance " <<
                  instanceId << std::endl;
    }
```

See the [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/ec2/monitor_instance.cpp).

## Disable Instance Monitoring
<a name="disable-instance-monitoring"></a>

To stop monitoring an instance, create an [UnmonitorInstancesRequest](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-ec2/html/class_aws_1_1_e_c2_1_1_model_1_1_unmonitor_instances_request.html) with the ID of the instance to stop monitoring, and pass it to the EC2Client’s `UnmonitorInstances` function.

 **Includes** 

```
#include <aws/ec2/EC2Client.h>
#include <aws/ec2/model/MonitorInstancesRequest.h>
#include <aws/ec2/model/UnmonitorInstancesRequest.h>
#include <iostream>
```

 **Code** 

```
    Aws::EC2::EC2Client ec2Client(clientConfiguration);
    Aws::EC2::Model::UnmonitorInstancesRequest unrequest;
    unrequest.AddInstanceIds(instanceId);
    unrequest.SetDryRun(true);

    Aws::EC2::Model::UnmonitorInstancesOutcome dryRunOutcome = ec2Client.UnmonitorInstances(unrequest);
    if (dryRunOutcome.IsSuccess()) {
        std::cerr
                << "Failed dry run to disable monitoring on instance. A dry run should trigger an error."
                <<
                std::endl;
        return false;
    } else if (dryRunOutcome.GetError().GetErrorType() !=
               Aws::EC2::EC2Errors::DRY_RUN_OPERATION) {
        std::cout << "Failed dry run to disable monitoring on instance " <<
                  instanceId << ": " << dryRunOutcome.GetError().GetMessage() <<
                  std::endl;
        return false;
    }

    unrequest.SetDryRun(false);
    Aws::EC2::Model::UnmonitorInstancesOutcome unmonitorInstancesOutcome = ec2Client.UnmonitorInstances(unrequest);
    if (!unmonitorInstancesOutcome.IsSuccess()) {
        std::cout << "Failed to disable monitoring on instance " << instanceId
                  << ": " << unmonitorInstancesOutcome.GetError().GetMessage() <<
                  std::endl;
    } else {
        std::cout << "Successfully disable monitoring on instance " <<
                  instanceId << std::endl;
    }
```

See the [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/ec2/monitor_instance.cpp).

## More Information
<a name="more-information"></a>
+  [RunInstances](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_RunInstances.html) in the Amazon EC2 API Reference
+  [DescribeInstances](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeInstances.html) in the Amazon EC2 API Reference
+  [StartInstances](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_StartInstances.html) in the Amazon EC2 API Reference
+  [StopInstances](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_StopInstances.html) in the Amazon EC2 API Reference
+  [RebootInstances](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_RebootInstances.html) in the Amazon EC2 API Reference
+  [DescribeInstances](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeInstances.html) in the Amazon EC2 API Reference
+  [MonitorInstances](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_MonitorInstances.html) in the Amazon EC2 API Reference
+  [UnmonitorInstances](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_UnmonitorInstances.html) in the Amazon EC2 API Reference