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The Official Blog of Mackerel

Temporary system shut down for database maintenance on December 19th (Thurs.)

Thank you for choosing Mackerel.

As stated in the title, system maintenance has been scheduled to take place on Thursday, December 19.

The system will be temporarily suspended and we apologize for any inconvenience that this may cause. Maintenance such as this is indispensable for being able to continuously provide better service and we appreciate your understanding.

Scheduled date and time

Thursday, December 19, 2019 from 2:00pm - 5:00pm (JST)

※This time period is the longest case scenario. The system will restart as soon as the maintenance work has been completed.

The reason for this date and time

Because Mackerel is a service that is relied upon for system monitoring, we came to the conclusion that the best time for a temporary shutdown would be at a time when the majority of Mackerel users could be available to keep an eye on things and respond if necessary. For this reason, we’ve scheduled the time window to avoid the middle of the night, commuting hours and lunch breaks for many of our users in Japan.

On the other hand, we understand that for those using Mackerel for server management, it will be difficult to perform actions such as server operations and deploying applications during the daytime and we sincerely apologize for the inconvenience.

Consideration for our users is essential in determining an appropriate maintenance timeframe and something that we want to continue to improve. If you have any feedback, please let us know.


To update the SSL/TLS certificate of the database system (Amazon RDS) used by Mackerel


  • The scheduled time frame is the longest case scenario and will end as soon as the work has been completed.
  • Once maintenance work has begun, the entire Mackerel system will shutdown for a short period of time.
    • Web access to Mackerel, data posting by the agent, API access (including the CLI tool), alert notifications, etc. will be unavailable during this time
  • As soon as the scheduled maintenance has been completed and working operation has been confirmed, the system shutdown will end and an announcement will be made
  • As for mackerel-agent metric posting, data will be buffered from mackerel-agent during the maintenance period and resent after maintenance has been completed
    • If resent properly, graphs during the maintenance period will also be displayed.
    • Please note that if mackerel-agent is stopped or restarted before resending is complete, buffering data will be lost.
    • Trying to start up mackerel-agent during maintenance will fail because communication with Mackerel cannot be made.


Situation reports will be made on the Mackerel status page (

We will also make periodical updates on our official Twitter account (

Related inquiries

Please send all inquiries regarding this matter to

Thank you again for your understanding and cooperation.

GraphBoard tabs are now rearrangeable and more

Hello. CRE Miura (id:missasan) here.

The mornings and evenings have finally started to feel like fall, but the lingering heat makes choosing what to wear quite a struggle.

This week we’ve released some pretty useful new functions like freely rearrangeable GraphBoard tabs and being able to use check monitoring result messages as action environment variables. Also, Mackerel’s very own Furukawa (id:masayoshi) is scheduled to be the keynote speaker at Cloud Native Days Kansai 2019 held at the end of November. Be sure to read until the end.

Now on to the new update information.

GraphBoard tabs are now rearrangeable

Hovering the cursor over a GraphBoard tab will display the arrow keys < and >. Click the arrow in the direction you would like to move the tab.


GraphBoards is a function that allows users to create a board and freely arrange graphs that are associated with certain services. Previously, tabs were only displayed in the order in which they were created, but this new release now allows you the ability to change that order arbitrarily.

Check monitoring result messages can now be passed as action environment variables

With the release of mackerel-agent v0.64.0, check monitoring execution result messages can now be used as action environment variables.

In the article below, Mackerel CRE Inoue (id:a-know) introduces a usage case for this function. In fact, Inoue made the Pull Request to post log monitoring results to graph annotations using the mkr command, so definitely check that out as well! (Japanese only)

If you have any other usage case ideas, be sure to publish it on your blog and let us know!

For more detailed check monitoring specifications, check out the link below.

Also, refer to the link below if using official plugins for check monitoring.

Automatic updates for the Alert Status widget

When automatic updates for custom dashboard graphs is enabled, the Alert Status widget content will now be automatically updated as well.

You can now distinguish whether a timestamp in the Monitors list refers to time created or last updated

When hovering the cursor over date/time information in the Monitors list screen, it now displays whether that time is the time of creation or last update.

The issue of differential metrics not being recognized with mackerel-plugin-solr has been fixed

With the release of mackerel-agent-plugins v0.59.0, the issue regarding mackerel-plugin-solr metrics not being recognized as differential metrics has been fixed.

Thank you to all the users who contributed Pull Requests for the OSS releases!

Mackerel team member Furukawa to be keynote speaker at Cloud Native Days Kansai 2019!

  • Speaker:Masahiro Furukawa SRE
  • Date and time of presentation: Thursday, November 28, 2019 11:20 am - 11:40 am (JST)
  • Title:Mackerel’s ongoing approach toward CloudNative 〜From on-premise to CloudNative〜
  • Summary:Mackerel, having launched from an on-premise environment in 2014, fully migrated to the cloud in 2017 and now sets its sights on CloudNative. In this presentation, we will introduce the evaluation criteria for each transition period and go over how Mackerel, which started with on-premise VM operation, is now attempting CloudNative. We’ll also touch on topics such as the latest infrastructure changes, team structure/culture and more.

go-check-plugins update

Hello. Mackerel team CRE id:a-know here bringing you this week’s updates.

go-check-plugins update

go-check-plugins has been updated to v0.32.0. The following functional changes were made.

  • [check-http] Authentication information for Basic authentication can now be specified in the form of --user USER:PASSWORD
  • [check-procs] The --pattern option can now be specified multiple times. The following is a usage example.
$ check-procs -p "sshd" -p "bash"
Procs OK:
Found 5 matching processes; cmd /sshd/
Found 2 matching processes; cmd /bash/

Thank you to everyone who contributed!

We’ve increased the number of seats for Mackerel Drink Up #9 Tokyo on October 23rd!

Due to high interest, we’ve increased the limited number of spots available to attend the recently announced Mackerel Drink Up #9 Tokyo! (Japanese only)

The theme of this event is “Recent Updates”. Thankfully, the LT quota has already been filled. There are still a few spots left, so please consider taking a break in the middle of the week and join us!

The release of the Alert Status widget and more

Hello. CRE Nishiyama (id:tukaelu) here.

The rugby world cup is really heating up. With Japan’s upset over Ireland, I really hope that they can advance for the first time!

Now on to this week’s update information.

The release of the Alert Status widget

The Alert Status widget has been added to the widgets available for custom dashboards.


With the Alert Status widget, you can display the alert statuses of all the hosts that belong to that role, arranged in order of Unknown, Critical, Warning, OK, and you can access each host details screen by clicking on their icons.

This makes it easier to keep an eye on host statuses and is particularly handy when numerous hosts belong to one role!

This function was actually implemented by students who participated in the Hatena Internship program, so be sure to try it out!!

Display of the date and time at which monitors are created/updated is now supported

The date and time at which a monitor is created/updated is now displayed.


The date and time at which a monitor was last updated is displayed from the Monitors list and both the date and time at which a monitor was created and last updated are displayed at the top of the monitor’s details page.

The registration error when a NIC name cannot be retrieved with Mackerel-agent for Windows has been resolved

Previously, a host registration error would occur when the NIC name could not be retrieved, but this problem was corrected with the mackerel-agent v0.63.0 to register without the unnamed NIC.

Mackerel’s 5 year anniversary!

Thank you for choosing Mackerel.

Mackerel Director id:daiksy here.

Mackerel was officially released just five years ago on September 17th, 2014. The beta was first released in May of that year and received it’s official release after a four-month trial period. The director at that time was Hatena's current CTO, id:motemen, and this was all about two months before I even joined Hatena. (Japanese only)

Back then, functions for service metrics monitoring and Slack notifications were still under development, but new functions were released every week based on the idea of starting out a service small and then growing it quickly.

If you take a look back at the Meetup report following the official release, you can get a glimpse of what it was like back then. (Japanese only)

After that, Mackerel's weekly feature releases would continue for 200 consecutive weeks.

And although there have been considerable changes in the environment surrounding system operation over the past 5 years, feedback from users like all of you has inspired the concepts for functions like mackerel-container-agent, Micro hosts, Anomaly Detection for Roles, etc., and has allowed us to continually improve and keep up with changes of time.


We look forward to seeing how another 5 years will shape the evolution of Mackerel.

Help us celebrate at some of the events we have planned out around the end of this year!

Downtime feature release and more

Hello. CRE Miura (id:missasan) here.

For a long time now we’ve been receiving many enthusiastic requests to release a downtime function that allows the user to stop monitoring at a specified time!

Leading up until now, Mackerel has had several functions for suspending monitoring or notifications, but in order to respond to scheduled batches and maintenance etc., the use of a separate scheduler function was required like with cron for LinuxOS, taking time and effort. With the release of this downtime feature, it is now possible to set up flexible schedules from Mackerel. And of course, it can also be configured from the API.

The Mackerel team is pleased to be able to provide a function that is directly connected to saving users time and effort. In addition to this, if there are changes that you would like to see made to other functions, please feel free to send us some feedback at【】. For open source related items, pull requests are also welcome!

Now on to this week’s update information.

Downtime feature release

We’ve released a function that allows you to suspend monitoring for a specified time period, for a target service/role or monitor. Recurrence settings such as hourly, daily, weekly (day of the week), monthly, and yearly are also available.

During the downtime’s configured time period, incidents will not appear on the alert list nor will notifications be sent to the notification channel, even if there are metric posts that conflict with the target monitor. (Metrics will be posted)

As described in the following use cases, this can be used in advance for load increases or for instances when the service is known to stop.

Use cases

  • Periodic batch processing
  • Scheduled maintenance periods

How to use

Downtime can be configured in the following two ways.

  • From the console screen
  • From the API

For more detailed information, check out the help page below.

Alert Group Settings API release

Alert Group Settings can now be obtained, created, updated, and deleted from the API.

For more details, check out the help page below.

WebSocket now supported with AWS Integration API Gateway

WebSocket related metrics can now be obtained. Check out the following help page for more details regarding obtainable metrics.

mackerel-plugin-solr now supports retrieving metrics for Apache Solr 7.x and 8.x

With mackerel-agent-plugins v0.58.0, Apache Solr 7.x and 8.x metrics can now be obtained in addition to the previously obtainable 5.x and 6.x.

-redis-namespace option added to mackerel-plugin-sidekiq

Also in mackerel-agent-plugins v0.58.0, the -redis-namespace option has been added to mackerel-plugin-sidekiq, and the key namespace can now be specified. If you use a gem like redis-namespace to give the Redis key a namespace, you can now get metrics by specifying this option.

Top-level tagging with Amazon API Gateway now supported and more

Hello. Mackerel team CRE Inoue (id:a-know) here. Recently, the summer heat has finally started to cool down.

Now let’s take a look at the update information that has come out since our last announcement.

Top-level tagging with Amazon API Gateway now supported

This is an announcement regarding the integration of API Gateway with Mackerel AWS Integration.

When API Gateway integration was released in November 2018, Amazon API Gateway only supported tags on Stages. For this reason, Mackerel also filtered using APIs that included stages.

In May 2019, Amazon API Gateway began tagging support for all top-level resources.

With this, Mackerel will also begin to offer the same support starting September 5th. The filter conditions for Mackerel's API Gateway integration will change as follows.

  • Tags will no longer be filtered by Stages
  • Only API tags will be targeted for filtering.

As a result of these changes, charges regarding API Gateway integration may fluctuate slightly. We apologize for the inconvenience to those of you currently using the service, but we will be reviewing the filter conditions around September 5. (For those of you already using API Gateway integration as of August 23, we have also contacted you directly.)

The release of mackerel-agent v0.62.0

The main changes in v0.62.0 are as follows.

  • The metadata plugin now supports the environment variable MACKEREL_PLUGIN_WORKDIR
  • Posting of unused system metrics ( , memory.inactive) has been stopped
    • If you are currently monitoring these items, please pay attention to the monitoring settings when updating the agent.
  • The process command name is now checked when checking the pid file.
    • This fixes the bug where mackerel-agent would not start up when the previous pid file is unintentionally left over and the OS is restarted.