ASG Multiple AZ
Ensures that ASGs are created to be cross-AZ for high availability.
ASGs can easily be configured to allow instances to launch in multiple availability zones. This ensures that the ASG can continue to scale, even when AWS is experiencing downtime in one or more zones.
Recommended Actions
Follow the appropriate remediation steps below to resolve the issue.
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Log in to the AWS Management Console and Search for “EC2” to reach EC2 dashboard.
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In the left navigation panel, scroll down and choose Auto Scaling Groups option under “Auto Scaling”.
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Select the Auto Scaling Group(s) that needs to be modified.
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Scroll down to select the “Details” tab and check the Availability Zone(s).
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If Availability Zone(s) value under “Network” is set to a single availability zone (e.g. us-east-1b), then it cannot launch instances to multiple Availability Zone(s). /br>
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Select the Auto Scaling Group and click on “Edit”.
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In the Edit Web-ASG page scroll down to “Network” and from the dropdown select the desired multiple availability zones one by one and add the Subnet(s) to make the Auto Scaling Group available to Multiple Availability Zone(s).
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Scroll down to the end of the page and click “Update” to save the changes.
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Go to “Details” tab and under “Network” check if the Availability Zone(s) shows multiple regions and subnets as well.
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Repeat the steps number 2 to 9 to check whether other Auto Scaling Group(s) are hosted in multiple Availability Zone(s) or not.