Please take part in the Sheriff Survey!

June 8th, 2016 by cbook


When we moved to the “inbound” model of tree management, the Tree Sheriffs became a crucial part of our engineering infrastructure. The primary responsibility of the Sheriffs is and will always be to aid developers to easily, quickly, and seamlessly land their code in the proper location(s) and ensure that code does not break our automated tests.

But of course there is always room for improvements and ideas how we can make things better. In order to get a picture from our Community (YOU!) how things went and how we can improve our day-to day-work we created a Survey!

You can find the Survey here:

Thanks for taking part in this survey!

Also you can find some of us also in London during the Mozilla All-hands if you want to talk to us directly!


– Tomcat

Sheriff Newsletter for January 2016

February 5th, 2016 by cbook
To give a little insight into our work and make our work more visible to our Community we decided to create a  monthly report of what’s going on in the Sheriffs Team.
If you have questions or feedback, just let us know!
In case you don’t know who the sheriffs are, or to check if there are current issues on the tree, see:
Topics of this month!
1. How-To article of the month
2. Get involved
3. Statistics for January
4. Orange Factor
5. Contact
1. How-To article of the month and notable things!
-> In the Sheriff Newsletter we mentioned the “Orange Factor” but what is this ?  It is simply the ratio of oranges (test failures) to test runs. The ideal value is, of course, zero.

Practically, this is virtually impossible for a code base of any substantial size,so it is a matter of policy as to what is an acceptable orange factor.

It is worth noting that the overall orange factor indicates nothing about the severity of the oranges. [4]

The main site where you can checkout the “Orange Factor” is at  and some interesting info’s are here
-> As you might be aware Firefox OS has moved into Tier 3 Support [5] – this means that there is no Sheriff Support anymore for the b2g-inbound tree.

Also with moving into tier-3 – b2g tests have also moved to tier 3 and this tests are by default “hidden” on treeherder. To view test results as example on treeherder for mozilla-central you need to click on the checkbox in the treeview “show/hide excluded jobs”.

2. Get involved!
Are you interested in helping out by becoming a Community Sheriff? Let us know!
3. Statistics
Intermittent Bugs filed in January  [1]: 667
and of those are closed: 107 [2]
For Tree Closing times and reasons see:
4. Orange Factor
Current Orangefactor [3]: 12.92
5.  How to contact us
There are a lot of ways to contact us. The fastest one is to contact
the sheriff on duty (the one with the |sheriffduty tag on their nick
🙂 or by emailing sheriffs @ mozilla dot org.

– Tomcat on the behalf of the Sheriffs

7 Years at Mozilla!

July 3rd, 2015 by cbook


since last month i’m now 7 years at Mozilla as full-time employee \o/

Of course I’m longer around because i started as Community Member in QA years before. And its a long way from my first steps at QA to my current role as Code Sheriff @ Mozilla.

I never actively planned to join the Mozilla Community it just happened 🙂 I worked back in 2001 at a German Email Provider as 2nd Level Support Engineer and as part of my Job (and also to Support Customers) we used different Email Programm’s to find out how to set-up the Programm and so.

Some Friends already involved into OpenSource (some linux fans) pointed me to this Mozilla Programm (at that time M1 or so) and i liked the Idea with this “Nightly”. Having everyday a brand new Program was something really cool and so started my way into the Community without even knowing that i’m now Part of the Community.

So over the years with Mozilla i finally filed my first bug and and was scared like hell (all this new fields in a non-native language) and not really knowing what i signed up when i clicked up this “submit” button in bugzillla 🙂  (was not even sure if i’m NOW supposed to fix the bug 🙂

And now i file dozens of Bugs every day while on Sheriffduty or doing other tasks 🙂

I learned a lot of stuff over the last years and still love being part of Mozilla  and its the best place to work for me! So on to the next years at Mozilla!

– Tomcat

a day in sheriffing

July 3rd, 2015 by cbook


since i talked with a lot of people about Sheriffing and what we do here is what a typical day for me look:

We care about the Code Trees like Test Failures etc

I usually start the day with checkin the trees we are responsible for  for test failures using treeherder. This gives me first a overview of the current status and as well make sure that everything is ok for the Asian and European Community which is online at that time.

This Tasks is ongoing till the end of my duty shift. From time to time this means we have to do backouts for code/test regressions.
Beside this i do stuff like checkin-neededs, uplifts etc and other tasks and of course always availble for questions etc on irc 🙂

Also i was thinking about some parts of my day-to-day experience:

Backouts and Tree Closures:

While backouts of code for test failures/bustages etc is one important task of sheriffs (and the managing of tree closures related to this), its always a mixed feeling to backout work from someone (and no one wants to cause a bustage) but its important to ensure quality of our products.

Try Server!!!

Tree Closures due to backouts can have the side effect that others are blocked with checkins. So if in doubt if your patch compile or could cause test regressions, please consider a try run, this helps at lot to keep tree closures for code issues at a minimum.

And last but not least Sheriffing is a Community Task! So if you want to be part of the Sheriff Team as Community Sheriff please sent me a mail at tomcat at mozilla dot com


– Tomcat

Results of the Sheriff Survey

April 1st, 2015 by cbook


we closed our Sheriff Survey on Monday and i wanted to share some highlights from the Results. Thanks for taking part in the Survey!

1.Communication with the Sheriffs

We got very good and positive Feedback about the Interaction/Communication with the Sheriffs. We know that backouts are never a good/positive thing and we sheriffs assume always the best intentions – nobody _wants_ to cause bustage, but it happens.

We also noticed a lot of comments of checkin-needed requestors and the hope we have at some time the autolander system (that lands patches automatically). There is work being done on this like as example in


2. Trychooser and other Feedback

We got comments about trychooser and how this could be improved. That Feedback is very valuable and we will pass that Feedback over to the Releng Folks. For all Feedback and Suggestions we are looking at the survey what we can improve and realize. As example one result is now 🙂


3. Getting Involved!

We got several Community Member with interest in helping out with Sheriffing! Thats really great and we will follow-up here soon. Also its not too late to get involved. Just drop me or the sheriff lists ( a note!


4. You can reach us at anytime!

While the Survey is closed now you can still contact us anytime for feedback, questions and when you want to be involved! Just drop us a note at or ping the Sheriff on duty (normally the one with the |sheriffduty tag in #developers on



– Tomcat

First overview from the sheriff survey!

March 24th, 2015 by cbook


thanks for all the Reply’s we got for the Sheriff Survey! If you haven’t already took part in it, its still online and you can still take part in the survey!

While we close the Survey in a few days and i will provide a comprehensive overview of course, i was feeling i could already do some quick overview what we got so far.

One big take away is how important checkin-needed requests is and how many people depend on this. We are very sorry if there are delays with picking up checkin-needed requests but since its a human task it depend how much is ongoing with the trees etc.

But there is work being done on Autoland like on 🙂

Also to follow up on 2 concrete things (you might know or maybe not).

Question: How do i know why the tree is closed (when we have a tree closure) on Treeherder

Answer:  Just hover over the repo name in Treeherder (as example mozilla-inbound) or click on the info button right next to the repo name

Question: When i land something on like mozilla-inbound its a mess to manually copy and past the hg changeset url to bug

Answer: We have a tool called mcmerge its right next to every push in the drown-down arrow action menu and unlike the name says its not just to mark merges. During the survey we found out that the name is misleading so we trying to find a new name –



– Tomcat

Please take part in the Sheriff Survey

March 17th, 2015 by cbook


When we moved to the “inbound” model of tree management, the Tree Sheriffs became a crucial part of our engineering infrastructure. The primary responsibility of the Sheriffs is and will always be to aid developers to easily, quickly, and seamlessly land their code in the proper location(s) and ensure that code does not break our automated tests. In the service of this objective, the Sheriffs work closely with the larger engineering organization to create and enforce landing policies that increase productivity while maintaining an efficient and robust automated testing system. Beyond the policy role, they have also become shepherds of automation quality by monitoring intermittent failures, performing uplifts and merges, and identifying poorly performing automation machines. This role has proven successful, and so a formal module for the Tree Sheriffs in the larger context of the Activities Module was created.

But of course there is always room for improvements and ideas how we can make things better. In order to get a picture from our Community how things went and how we can improve our day-to day-work.

So we created the Sheriff Survey here ->
Thanks for taking part in that!

– The Mozilla Tree Sheriffs!

Vortrag ueber Mozilla Sheriffs heute beim OpenSource Treffen in Muenchen

November 27th, 2014 by cbook


ich werde heute ab 18 Uhr wieder beim OpenSource Treffen in Muenchen dabei sein und dabei etwas erzaehlen ueber Mozilla Code Sheriffs.

Natuerlich werde ich auch fuer allgemeine Fragen rund um Mozilla zur Verfuegung stehen.

Dann bis heute abend!


Viele Gruesse


Mozilla Plugincheck – Its a Community Thing

October 10th, 2014 by cbook


A lot of people are using Mozilla’s Plugincheck Page to make sure all the Plugins like Adobe Flash are up-to-date.

Schalk Neethling has create a great Blog Post about Plugincheck here.

So if you are interested in contributing to Plugincheck check out Schalk’s Blogpost!



– Tomcat

The past, Current and future

October 10th, 2014 by cbook

– The past –
I’m now about a year member of the A-Team (Automation and Tools Team) and also Fulltime Sheriff.

It was the end of a lot of changes personal and job wise. I moved from the Alps to the Munich Area to the City of Freising and (and NO i was not at the Beer Oktoberfest 😉 and working as Fulltime Sheriff after my QA/Partner Build and Releng Duties.

Its awesome to be part of the Sheriff Team and was also awesome to get so much help from the Team like from Ed, Wes and Ryan to get started.

At one time i took over the Sheriff-Duty for my European Timezone and it was quite challenging having the responsible for all the Code Trees with Backouts etc and also later checkin-neededs 🙂 What i really like as Sheriff is the work across the different Divisions at Mozilla and its exciting to work as Mozilla Sheriff too 🙂

One of main contribution beside getting started was helping creating some How-To Articles at . I hope that will help also others to get involved into sheriffing.

– Current –

We just switched over to use Treeherder as new tool for Sheriffing.

Its quite new and so it feels (as everything like a new car there are this questions like how i do things i used to do in my old car etc) and there are still some bugs and things we can improve but we will get there. Also its a ideal time for getting involved into sheriffing like with hammering on Treeherder.

and that leads into ….:)

– The Future is You – !

As every Open Source Project Mozilla is heavily depended on Community Members like you and there is even the oppourtunity beside all the other Areas at Mozilla to work as Community Sheriff.So let us know if you want to be involved as Community-Sheriff. You are always welcome. You can find us in the #ateam Channel on

For myself i’m planning to work beside my other tasks more in Community Building like blogging about Sheriffing and also taking more part in the Open Source Meetings in Munich.

– Tomcat