Auto Scaling examples using SDK for PHP - AWS SDK Code Examples
ActionsScenarios

There are more AWS SDK examples available in the AWS Doc SDK Examples GitHub repo.

Auto Scaling examples using SDK for PHP

The following code examples show you how to perform actions and implement common scenarios by using the AWS SDK for PHP with Auto Scaling.

Actions are code excerpts from larger programs and must be run in context. While actions show you how to call individual service functions, you can see actions in context in their related scenarios and cross-service examples.

Scenarios are code examples that show you how to accomplish a specific task by calling multiple functions within the same service.

Each example includes a link to GitHub, where you can find instructions on how to set up and run the code in context.

Get started

The following code examples show how to get started using Auto Scaling.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function helloService()
    {
        $autoScalingClient = new AutoScalingClient([
            'region' => 'us-west-2',
            'version' => 'latest',
            'profile' => 'default',
        ]);

        $groups = $autoScalingClient->describeAutoScalingGroups([]);
        var_dump($groups);
    }

Actions

The following code example shows how to use CreateAutoScalingGroup.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function createAutoScalingGroup(
        $autoScalingGroupName,
        $availabilityZones,
        $minSize,
        $maxSize,
        $launchTemplateId
    ) {
        return $this->autoScalingClient->createAutoScalingGroup([
            'AutoScalingGroupName' => $autoScalingGroupName,
            'AvailabilityZones' => $availabilityZones,
            'MinSize' => $minSize,
            'MaxSize' => $maxSize,
            'LaunchTemplate' => [
                'LaunchTemplateId' => $launchTemplateId,
            ],
        ]);
    }

The following code example shows how to use DeleteAutoScalingGroup.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function deleteAutoScalingGroup($autoScalingGroupName)
    {
        return $this->autoScalingClient->deleteAutoScalingGroup([
            'AutoScalingGroupName' => $autoScalingGroupName,
            'ForceDelete' => true,
        ]);
    }

The following code example shows how to use DescribeAutoScalingGroups.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function describeAutoScalingGroups($autoScalingGroupNames)
    {
        return $this->autoScalingClient->describeAutoScalingGroups([
            'AutoScalingGroupNames' => $autoScalingGroupNames
        ]);
    }

The following code example shows how to use DescribeAutoScalingInstances.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function describeAutoScalingInstances($instanceIds)
    {
        return $this->autoScalingClient->describeAutoScalingInstances([
            'InstanceIds' => $instanceIds
        ]);
    }

The following code example shows how to use DescribeScalingActivities.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function describeScalingActivities($autoScalingGroupName)
    {
        return $this->autoScalingClient->describeScalingActivities([
            'AutoScalingGroupName' => $autoScalingGroupName,
        ]);
    }

The following code example shows how to use DisableMetricsCollection.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function disableMetricsCollection($autoScalingGroupName)
    {
        return $this->autoScalingClient->disableMetricsCollection([
            'AutoScalingGroupName' => $autoScalingGroupName,
        ]);
    }

The following code example shows how to use EnableMetricsCollection.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function enableMetricsCollection($autoScalingGroupName, $granularity)
    {
        return $this->autoScalingClient->enableMetricsCollection([
            'AutoScalingGroupName' => $autoScalingGroupName,
            'Granularity' => $granularity,
        ]);
    }

The following code example shows how to use SetDesiredCapacity.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function setDesiredCapacity($autoScalingGroupName, $desiredCapacity)
    {
        return $this->autoScalingClient->setDesiredCapacity([
            'AutoScalingGroupName' => $autoScalingGroupName,
            'DesiredCapacity' => $desiredCapacity,
        ]);
    }

The following code example shows how to use TerminateInstanceInAutoScalingGroup.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function terminateInstanceInAutoScalingGroup(
        $instanceId,
        $shouldDecrementDesiredCapacity = true,
        $attempts = 0
    ) {
        try {
            return $this->autoScalingClient->terminateInstanceInAutoScalingGroup([
                'InstanceId' => $instanceId,
                'ShouldDecrementDesiredCapacity' => $shouldDecrementDesiredCapacity,
            ]);
        } catch (AutoScalingException $exception) {
            if ($exception->getAwsErrorCode() == "ScalingActivityInProgress" && $attempts < 5) {
                error_log("Cannot terminate an instance while it is still pending. Waiting then trying again.");
                sleep(5 * (1 + $attempts));
                return $this->terminateInstanceInAutoScalingGroup(
                    $instanceId,
                    $shouldDecrementDesiredCapacity,
                    ++$attempts
                );
            } else {
                throw $exception;
            }
        }
    }

The following code example shows how to use UpdateAutoScalingGroup.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

    public function updateAutoScalingGroup($autoScalingGroupName, $args)
    {
        if (array_key_exists('MaxSize', $args)) {
            $maxSize = ['MaxSize' => $args['MaxSize']];
        } else {
            $maxSize = [];
        }
        if (array_key_exists('MinSize', $args)) {
            $minSize = ['MinSize' => $args['MinSize']];
        } else {
            $minSize = [];
        }
        $parameters = ['AutoScalingGroupName' => $autoScalingGroupName];
        $parameters = array_merge($parameters, $minSize, $maxSize);
        return $this->autoScalingClient->updateAutoScalingGroup($parameters);
    }

Scenarios

The following code example shows how to:

  • Create an Amazon EC2 Auto Scaling group with a launch template and Availability Zones, and get information about running instances.

  • Enable Amazon CloudWatch metrics collection.

  • Update the group's desired capacity and wait for an instance to start.

  • Terminate an instance in the group.

  • List scaling activities that occur in response to user requests and capacity changes.

  • Get statistics for CloudWatch metrics, then clean up resources.

SDK for PHP
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository. 

namespace AutoScaling;

use Aws\AutoScaling\AutoScalingClient;
use Aws\CloudWatch\CloudWatchClient;
use Aws\Ec2\Ec2Client;
use AwsUtilities\AWSServiceClass;
use AwsUtilities\RunnableExample;

class GettingStartedWithAutoScaling implements RunnableExample
{
    protected Ec2Client $ec2Client;
    protected AutoScalingClient $autoScalingClient;
    protected AutoScalingService $autoScalingService;
    protected CloudWatchClient $cloudWatchClient;
    protected string $templateName;
    protected string $autoScalingGroupName;
    protected array $role;

    public function runExample()
    {
        echo("\n");
        echo("--------------------------------------\n");
        print("Welcome to the Amazon EC2 Auto Scaling getting started demo using PHP!\n");
        echo("--------------------------------------\n");

        $clientArgs = [
            'region' => 'us-west-2',
            'version' => 'latest',
            'profile' => 'default',
        ];
        $uniqid = uniqid();

        $this->autoScalingClient = new AutoScalingClient($clientArgs);
        $this->autoScalingService = new AutoScalingService($this->autoScalingClient);
        $this->cloudWatchClient = new CloudWatchClient($clientArgs);

        AWSServiceClass::$waitTime = 5;
        AWSServiceClass::$maxWaitAttempts = 20;

        /**
         * Step 0: Create an EC2 launch template that you'll use to create an Auto Scaling group.
         */
        $this->ec2Client = new EC2Client($clientArgs);
        $this->templateName = "example_launch_template_$uniqid";
        $instanceType = "t1.micro";
        $amiId = "ami-0ca285d4c2cda3300";
        $launchTemplate = $this->ec2Client->createLaunchTemplate(
            [
            'LaunchTemplateName' => $this->templateName,
            'LaunchTemplateData' => [
                'InstanceType' => $instanceType,
                'ImageId' => $amiId,
            ]
            ]
        );

        /**
         * Step 1: CreateAutoScalingGroup: pass it the launch template you created in step 0.
         */
        $availabilityZones[] = $this->ec2Client->describeAvailabilityZones([])['AvailabilityZones'][1]['ZoneName'];

        $this->autoScalingGroupName = "demoAutoScalingGroupName_$uniqid";
        $minSize = 1;
        $maxSize = 1;
        $launchTemplateId = $launchTemplate['LaunchTemplate']['LaunchTemplateId'];
        $this->autoScalingService->createAutoScalingGroup(
            $this->autoScalingGroupName,
            $availabilityZones,
            $minSize,
            $maxSize,
            $launchTemplateId
        );

        $this->autoScalingService->waitUntilGroupInService([$this->autoScalingGroupName]);
        $autoScalingGroup = $this->autoScalingService->describeAutoScalingGroups([$this->autoScalingGroupName]);

        /**
         * Step 2: DescribeAutoScalingInstances: show that one instance has launched.
         */
        $instanceIds = [$autoScalingGroup['AutoScalingGroups'][0]['Instances'][0]['InstanceId']];
        $instances = $this->autoScalingService->describeAutoScalingInstances($instanceIds);
        echo "The Auto Scaling group {$this->autoScalingGroupName} was created successfully.\n";
        echo count($instances['AutoScalingInstances']) . " instances were created for the group.\n";
        echo $autoScalingGroup['AutoScalingGroups'][0]['MaxSize'] . " is the max number of instances for the group.\n";

        /**
         * Step 3: EnableMetricsCollection: enable all metrics or a subset.
         */
        $this->autoScalingService->enableMetricsCollection($this->autoScalingGroupName, "1Minute");

        /**
         * Step 4: UpdateAutoScalingGroup: update max size to 3.
         */
        echo "Updating the max number of instances to 3.\n";
        $this->autoScalingService->updateAutoScalingGroup($this->autoScalingGroupName, ['MaxSize' => 3]);

        /**
         * Step 5: DescribeAutoScalingGroups: show the current state of the group.
         */
        $autoScalingGroup = $this->autoScalingService->describeAutoScalingGroups([$this->autoScalingGroupName]);
        echo $autoScalingGroup['AutoScalingGroups'][0]['MaxSize'];
        echo " is the updated max number of instances for the group.\n";

        $limits = $this->autoScalingService->describeAccountLimits();
        echo "Here are your account limits:\n";
        echo "MaxNumberOfAutoScalingGroups: {$limits['MaxNumberOfAutoScalingGroups']}\n";
        echo "MaxNumberOfLaunchConfigurations: {$limits['MaxNumberOfLaunchConfigurations']}\n";
        echo "NumberOfAutoScalingGroups: {$limits['NumberOfAutoScalingGroups']}\n";
        echo "NumberOfLaunchConfigurations: {$limits['NumberOfLaunchConfigurations']}\n";

        /**
         * Step 6: SetDesiredCapacity: set desired capacity to 2.
         */
        $this->autoScalingService->setDesiredCapacity($this->autoScalingGroupName, 2);
        sleep(10); // Wait for the group to start processing the request.
        $this->autoScalingService->waitUntilGroupInService([$this->autoScalingGroupName]);

        /**
         * Step 7: DescribeAutoScalingInstances: show that two instances are launched.
         */
        $autoScalingGroups = $this->autoScalingService->describeAutoScalingGroups([$this->autoScalingGroupName]);
        foreach ($autoScalingGroups['AutoScalingGroups'] as $autoScalingGroup) {
            echo "There is a group named: {$autoScalingGroup['AutoScalingGroupName']}";
            echo "with an ARN of {$autoScalingGroup['AutoScalingGroupARN']}.\n";
            foreach ($autoScalingGroup['Instances'] as $instance) {
                echo "{$autoScalingGroup['AutoScalingGroupName']} has an instance with id of: ";
                echo "{$instance['InstanceId']} and a lifecycle state of: {$instance['LifecycleState']}.\n";
            }
        }

        /**
         * Step 8: TerminateInstanceInAutoScalingGroup: terminate one of the instances in the group.
         */
        $this->autoScalingService->terminateInstanceInAutoScalingGroup($instance['InstanceId'], false);
        do {
            sleep(10);
            $instances = $this->autoScalingService->describeAutoScalingInstances([$instance['InstanceId']]);
        } while (count($instances['AutoScalingInstances']) > 0);
        do {
            sleep(10);
            $autoScalingGroups = $this->autoScalingService->describeAutoScalingGroups([$this->autoScalingGroupName]);
            $instances = $autoScalingGroups['AutoScalingGroups'][0]['Instances'];
        } while (count($instances) < 2);
        $this->autoScalingService->waitUntilGroupInService([$this->autoScalingGroupName]);
        foreach ($autoScalingGroups['AutoScalingGroups'] as $autoScalingGroup) {
            echo "There is a group named: {$autoScalingGroup['AutoScalingGroupName']}";
            echo "with an ARN of {$autoScalingGroup['AutoScalingGroupARN']}.\n";
            foreach ($autoScalingGroup['Instances'] as $instance) {
                echo "{$autoScalingGroup['AutoScalingGroupName']} has an instance with id of: ";
                echo "{$instance['InstanceId']} and a lifecycle state of: {$instance['LifecycleState']}.\n";
            }
        }

        /**
         * Step 9: DescribeScalingActivities: list the scaling activities that have occurred for the group so far.
         */
        $activities = $this->autoScalingService->describeScalingActivities($autoScalingGroup['AutoScalingGroupName']);
        echo "We found " . count($activities['Activities']) . " activities.\n";
        foreach ($activities['Activities'] as $activity) {
            echo "{$activity['ActivityId']} - {$activity['StartTime']} - {$activity['Description']}\n";
        }

        /**
         * Step 10: Use the Amazon CloudWatch API to get and show some metrics collected for the group.
         */
        $metricsNamespace = 'AWS/AutoScaling';
        $metricsDimensions = [
            [
                'Name' => 'AutoScalingGroupName',
                'Value' => $autoScalingGroup['AutoScalingGroupName'],
            ],
        ];
        $metrics = $this->cloudWatchClient->listMetrics(
            [
            'Dimensions' => $metricsDimensions,
            'Namespace' => $metricsNamespace,
            ]
        );
        foreach ($metrics['Metrics'] as $metric) {
            $timespan = 5;
            if ($metric['MetricName'] != 'GroupTotalCapacity' && $metric['MetricName'] != 'GroupMaxSize') {
                continue;
            }
            echo "Over the last $timespan minutes, {$metric['MetricName']} recorded:\n";
            $stats = $this->cloudWatchClient->getMetricStatistics(
                [
                'Dimensions' => $metricsDimensions,
                'EndTime' => time(),
                'StartTime' => time() - (5 * 60),
                'MetricName' => $metric['MetricName'],
                'Namespace' => $metricsNamespace,
                'Period' => 60,
                'Statistics' => ['Sum'],
                ]
            );
            foreach ($stats['Datapoints'] as $stat) {
                echo "{$stat['Timestamp']}: {$stat['Sum']}\n";
            }
        }

        return $instances;
    }

    public function cleanUp()
    {
        /**
         * Step 11: DisableMetricsCollection: disable all metrics.
         */
        $this->autoScalingService->disableMetricsCollection($this->autoScalingGroupName);

        /**
         * Step 12: DeleteAutoScalingGroup: to delete the group you must stop all instances.
         * - UpdateAutoScalingGroup with MinSize=0
         * - TerminateInstanceInAutoScalingGroup for each instance,
         *     specify ShouldDecrementDesiredCapacity=True. Wait for instances to stop.
         * - Now you can delete the group.
         */
        $this->autoScalingService->updateAutoScalingGroup($this->autoScalingGroupName, ['MinSize' => 0]);
        $this->autoScalingService->terminateAllInstancesInAutoScalingGroup($this->autoScalingGroupName);
        $this->autoScalingService->waitUntilGroupInService([$this->autoScalingGroupName]);
        $this->autoScalingService->deleteAutoScalingGroup($this->autoScalingGroupName);

        /**
         * Step 13: Delete launch template.
         */
        $this->ec2Client->deleteLaunchTemplate(
            [
            'LaunchTemplateName' => $this->templateName,
            ]
        );
    }

    public function helloService()
    {
        $autoScalingClient = new AutoScalingClient([
            'region' => 'us-west-2',
            'version' => 'latest',
            'profile' => 'default',
        ]);

        $groups = $autoScalingClient->describeAutoScalingGroups([]);
        var_dump($groups);
    }
}