AWS autoscaling documentation change
Summary
Formatting changes (colon to em dash in bullet points) and added documentation about instance refresh limitations with attribute-based instance selection
Security assessment
The changes clarify operational constraints (unsupported parameters with attribute-based instance selection) and formatting. While the user data section mentions ensuring code updates, this is a pre-existing security best practice recommendation, not a new security feature or vulnerability fix.
Diff
diff --git a/autoscaling/ec2/userguide/instance-refresh-overview.md b/autoscaling/ec2/userguide/instance-refresh-overview.md index d8d71b0c9..471508738 100644 --- a//autoscaling/ec2/userguide/instance-refresh-overview.md +++ b//autoscaling/ec2/userguide/instance-refresh-overview.md @@ -139 +139 @@ For information about how compatibility is determined, see [Compatibility for ch - * **Total duration** : The maximum amount of time that an instance refresh can continue to actively replace instances is 14 days. + * **Total duration** — The maximum amount of time that an instance refresh can continue to actively replace instances is 14 days. @@ -141 +141 @@ For information about how compatibility is determined, see [Compatibility for ch - * **Difference in behavior specific to weighted groups** : If a mixed instances group is configured with an instance weight that is larger than or equal to the group's desired capacity, Amazon EC2 Auto Scaling might replace all `InService` instances at once. To avoid this situation, follow the recommendation in the [Configure an Auto Scaling group to use instance weights](./ec2-auto-scaling-mixed-instances-groups-instance-weighting.html) topic. Specify a desired capacity that is larger than your largest weight when you use weights with your Auto Scaling group. + * **Difference in behavior specific to weighted groups** — If a mixed instances group is configured with an instance weight that is larger than or equal to the group's desired capacity, Amazon EC2 Auto Scaling might replace all `InService` instances at once. To avoid this situation, follow the recommendation in the [Configure an Auto Scaling group to use instance weights](./ec2-auto-scaling-mixed-instances-groups-instance-weighting.html) topic. Specify a desired capacity that is larger than your largest weight when you use weights with your Auto Scaling group. @@ -143 +143 @@ For information about how compatibility is determined, see [Compatibility for ch - * **One-hour timeout** : When an instance refresh is unable to continue making replacements because it is waiting to replace instances on standby or protected from scale in, or the new instances do not pass their health checks, Amazon EC2 Auto Scaling keeps retrying for an hour. It also provides a status message to help you resolve the issue. If the problem persists after an hour, the operation fails. The intention is to give it time to recover if there is a temporary issue. + * **One-hour timeout** — When an instance refresh is unable to continue making replacements because it is waiting to replace instances on standby or protected from scale in, or the new instances do not pass their health checks, Amazon EC2 Auto Scaling keeps retrying for an hour. It also provides a status message to help you resolve the issue. If the problem persists after an hour, the operation fails. The intention is to give it time to recover if there is a temporary issue. @@ -145 +145 @@ For information about how compatibility is determined, see [Compatibility for ch - * **Deploying code via user data** : Skip matching doesn't check for code changes that are deployed from a user data script. If you use user data to pull new code and install these updates on new instances, we recommend that you turn off skip matching to make sure that all instances receive your latest code, even without a launch template version update. + * **Deploying code via user data** — Skip matching doesn't check for code changes that are deployed from a user data script. If you use user data to pull new code and install these updates on new instances, we recommend that you turn off skip matching to make sure that all instances receive your latest code, even without a launch template version update. @@ -147 +147,9 @@ For information about how compatibility is determined, see [Compatibility for ch - * **Update restriction** : If you attempt to update an Auto Scaling group's launch template, launch configuration, or mixed instances policy while an instance refresh with a desired configuration is active, the request will fail with the following validation error: `An active instance refresh with a desired configuration exists. All configuration options derived from the desired configuration are not available for update while the instance refresh is active.` + * **Update restriction** — If you attempt to update an Auto Scaling group's launch template, launch configuration, or mixed instances policy while an instance refresh with a desired configuration is active, the request will fail with the following validation error: `An active instance refresh with a desired configuration exists. All configuration options derived from the desired configuration are not available for update while the instance refresh is active.` + + * **Attribute-based instance selection** — If your Auto Scaling group uses attribute-based instance selection (specifying `InstanceRequirements` in a mixed instances policy), the following instance refresh parameters aren't supported: + + * **SkipMatching** \- An instance refresh will fail if you start it with the `SkipMatching` parameter in an Auto Scaling group that has `InstanceRequirements` configured. + + * **DesiredConfiguration** \- An instance refresh will fail if you start it with the `DesiredConfiguration` parameter in an Auto Scaling group that has `InstanceRequirements` configured. + +If you need to perform an instance refresh on an Auto Scaling group with attribute-based instance selection, start the instance refresh without these parameters.