Hello, this is Sudo ( 
id:do-su-0805 ) from Mackerel's CRE Team. Allow me to outline the updates in this release.
- Support for automatic retirement of RDS hosts linked by AWS intergration
- Additional services added to automatic roles assignment based on AWS tags for AWS Integration
- API keys in the Mackerel console are now masked
- mkr now supports metrics list display
- Accessibility improvements
- Bug fixes
Support for automatic retirement of RDS hosts linked by AWS intergration
Previously, only EC2 hosts could be automatically retired for hosts integrated with AWS. However, with this update, RDS hosts can now be automatically retired too.
When you enable this feature, the retirement process will be automatically executed in Mackerel when the corresponding host is deleted on AWS. To enable this feature, toggle the check mark on the "Enable automatic retirement" option in AWS integration settings page.
- If you have AWS integration turned on: Automatic retirement for RDS will be disabled. To enable it, toggle the check mark on the "Enable automatic retirement" option.
- If you have just turned on AWS integration: Automatic retirement for RDS will be enabled by default.
For detailed instructions, please refer to the "Configure automatic retirement" section at AWS Integration - Mackerel Docs.
Additional services added to automatic roles assignment based on AWS tags for AWS Integration
CloudFront, DynamoDB, Elasticsearch Service, and S3 have been added as services that can have roles automatically assigned based on AWS tags in Mackerel. By attaching the 'mackerel-integration' tag to AWS resources, the corresponding resources will be linked to Mackerel, and roles will be assigned based on the tag contents. This feature is available for services with a tag icon in the upper right corner of their symbol on the AWS integration settings page.
For detailed instructions, please refer to the "Assigning roles by tags" section at AWS Integration - Mackerel Docs Please also refer to the announcement at the time of this feature's release , which includes Q&A and use case examples.
API keys in the Mackerel console are now masked
API keys are now displayed with masking on the organization overview page and API key page. You can still copy the API key to a clipboard even when it is masked. If you want to view the content of the API key, you can toggle the display/hidden state for each API key by clicking on the display icon.
Masking the API key values makes it easier to take screenshots or share your screen. Please make use of it when sharing information internally or for demos.
mkr now supports metrics list display
The 'metric-names' command has been added to mkr, allowing you to display a list of the metric names associated with hosts or services.
For metrics associated with a host, you can retrieve them by executing either of the following commands:
$ mkr metric-names -H <Host ID> $ mkr metric-names --host <Host ID>
For metrics associated with a service, you can retrieve them by executing either of the following commands:
$ mkr metric-names -s <Service Name> $ mkr metric-names --service <Service Name>
This feature is available from mkr v0.50.0. Please update to use it.
This feature was contributed by 
id:sfujiwara. Thank you very much for this!
Accessibility improvements
Hints can now be displayed using keyboard operations on certain pages.
Some pages on the Mackerel console have "?" marks, and hovering over the "?" mark with the mouse cursor displays a tooltip explaining the function. We have improved this feature to make it available using keyboard operations too.
This feature is now available on dashboard editing page, channel settings page, notification group editing page, and role anomaly detection settings page.
Bug fixes
In the mackerel-plugin-twemproxy, we have fixed the issue where the metrics that should be output for "Server Error" and "Server Timeout" were swapped.
This fix is available from mackerel-agent-plugins v0.78.1. Please update to see the changes.
