Adding graph annotations is now easier, etc.

Hello. This is Nishiyama (id:tukaelu), the Mackerel team’s CRE. The details of this update are as follows.

Adding graph annotations is now easier

Do you know about the graph annotation feature, which allows you to add arbitrary information to the graphs of service metrics and roles?

Although you may have heard of it before, you may have often wondered where these annotations can be set. This update has improved the feature so that the following “Graph Annotations” icon is displayed whenever you hover the cursor over a spot where graph annotations can be set.

The Graph Annotations icon

This feature will look like the following on the actual web console, which we believe will make setting graph annotations even easier!

This icon will be displayed, making graph annotations easier to set.

Graph annotation is a very useful feature when you are referring back to the graph and in other situations! Please make use of this feature with reference to the help page.

The Chatwork API Token is no longer displayed in the list of notification channels

The Room ID and API Token were previously displayed in the list of notification channels for registered Chatwork channels, but for security reasons, we have improved the interface so that the API Token is no longer displayed.

We will continue to make improvements to ensure that our service is as safe and convenient as possible for users.

Fixed an issue where CPU usage temporarily spikes when restarting containers with mackerel-plugin-docker

There was an issue where graphs displayed a temporary spike in CPU usage that did not reflect actual CPU usage when a Docker container monitored by the mackerel-plugin-docker plugin was restarted. In this update, we have fixed this issue by detecting counter resets due to restarts and retrieving the appropriate metrics.

Please refer to the pull request page for more information.

Supported TLS versions for URL external monitoring have been changed to TLS 1.2 and later versions

TLS versions supported by Mackerel’s URL external monitoring have been changed to TLS 1.2 and later versions.

As [announced previously] (, serious vulnerabilities were reported in TLS 1.0 and TLS 1.1, which have been officially discontinued and deprecated in RFC 8996 as advised in March 2021.

Since TLS 1.0 and TLS 1.1 have been deprecated in many operating systems and browsers, Mackerel has also adopted the same measure.

Please be assured that we will continue to support encrypted communication on TLS 1.2 and later versions.

Mackerel Drink Up #11 Tokyo will be held on September 26th (Tuesday)!

As announced previously, we will be holding Drink Up #11 next Tuesday, September 26th, on the theme of how to make the most of Mackerel.

Two members of the Mackerel team, an app engineer who is personally involved in Mackerel’s development and a CRE member who used to work as an SRE, will be speaking at the event.

Only Mackerel users may attend the event, but users on the Free Plan are welcome too! If you are considering using Mackerel or are curious about what kind of service we are, please register for the Free Plan and join us at the event.

To attend the event, please register on the following connpass page.